Legacy Data Guide

This page contains detailed, historic reference information about the DASCH data products. Unfortunately it’s pretty messy, and some sections are out of date. We aim to migrate this information into a series of guides associated with each data release.

See also the summary of current, known data issues. If you get stuck trying to decipher anything here, try inquiring on the DASCH Astrophysics email list.

Database Variables

Table of Variables Used in the Photometry Database
variableName datatype unit variableDescription
A2FLAGS int Additional photometry warning flags
adjacentburstdip int ct A measure of the number of adjacent nburst3/4 and ndip3/4 points in a lightcurve
adjacentburstdip2 int ct A measure of the number of >5 adjacent nburst3/4 and ndip3/4 points in a lightcurve
adjacentburstdip3 int ct A measure of the number of >7 adjacent points 2-sigma above or below the median value of a lightcurve
AFLAGS int Photometry warning flags
AFLAGSBits char Listing of bits set in the photometry warning flags
AFLAGS_1 int Photometry warning flags
AFLAGS_2 int Photometry warning flags
aLength double pix Image long semi-axis in pixels
aLength_1 double pix Image long semi-axis in pixels
aLength_2 double pix Image long semi-axis in pixels
alternateDate char Y-M-D,h:m:s Alternate dark, flatfield, or linearity test for failed test
altitude double deg Height of the object above the horizon in degrees
analysis_threshold double ratio of FLUX_MAX/THRESHOLD used to select best data for search_close
aperture double m Telescope aperture in meters. Some series, notably mb, contain plates from serveral telescopes.
arraysize int ct Length of a variable character string
aveADU int ct Average ADU level for all of the tile
aveLengthRatio double pix Average aLength/bLength SExtractor images in a candidate scratch chain
aveNeighborCt double ct Average number of neighbering matched SExtractor images in a candidate scratch chain
aveTileSaturation int ct Average number of saturated pixels per tile
B2FLAGS int Additional photometry processing flags
BACKGROUND double ct Background at centroid position
BACKGROUND_1 double ct Background at centroid position
BACKGROUND_2 double ct Background at centroid position
background_ratio double ct (Image filtered background background)/(filtered background RMS)
badMaskFlag int If 1, mask flatfield has noise issues; if 0 mask flatfield is o.k.; if -1 indeterminant file name
BFLAGS int Photometry processing flags
BFLAGSBits char Listing of bits set in the photometry processing flags
BFLAGS_1 int Photometry processing flags
BFLAGS_2 int Photometry processing flags
binning int Binning (1x1 or 16x16) of the mosaic used for WCS fitting
bin_count int ct Number of images in a spatial bin.
bin_sum double ct Normalized correlation probability
Blendedmag double mag For case B and BD objects, the effective magnitude of all of the GSC2.3.2 objects within the blend.
Blendedmag_1 double mag For case B and BD objects, the effective magnitude of all of the GSC2.3.2 objects within the blend.
Blendedmag_2 double mag For case B and BD objects, the effective magnitude of all of the GSC2.3.2 objects within the blend.
bLength double pix Image short semi-axis in pixels
bLength_1 double pix Image short semi-axis in pixels
bLength_2 double pix Image short semi-axis in pixels
bmag0 double mag edge of magnitude bin for magnitude-dependent calibration
bmagerr double mag Johnson b magnitude error
border int pix Crop border in pixels. WCStools 'imwcs' input parameter.
bottomMargin int pix Bottom margin in pixels
bound enum bit Bound 'b' or unbound 'u' logbooks
bright_magcor_error double mag magcal_local_error for brightest two magnitudes
bright_magcor_local double mag magcor_local for brightest two magnitudes
bright_npoints_local int ct npoints_local for brightest two magnitudes
BTmag double mag GSC2.3.2 Tycho2 blue magnitude
BTminusVTmag double mag Tycho2 BT-VT color
calcTimeType char Calculated Date Type: (EST, LST, UT, SAST, ...)
calibrationDate char Y-M-D,h:m:s Date of dark, flatfield, or linearity test
calibrationStatus set calibration test status: acquired, processed, failed, or deleted
calibrationType set calibration test type: dark, flat, or linearity
CAL_FLAG int Deprecated, now part of BFLAGS
cal_local int bit If 1, local calibration was used; otherwise 0; becomes part of BFLAGS
cal_local_1 int bit If 1, local calibration was used; otherwise 0; becomes part of BFLAGS
cal_local_2 int bit If 1, local calibration was used; otherwise 0; becomes part of BFLAGS
capacity int byte9 Disk capacity in gigabytes
catalog enum Fitting catalog 'imwsky2k' or 'imwty2'. WCStools 'imwcs' input parameter.
catalogDistDifferentMag int ct Histogram of the distances of DASCH objects from nearby catalog objects differing by more than 2 magnitudes
catalogDistSimilarMag int ct Histogram of the distances of DASCH objects from nearby catalog objects within 2 magnitudes
catalogDistTotal int ct Histogram of the distances of DASCH objects from nearby catalog objects
catalogmag double mag Magnitude from variable star or galaxy catalog. Miscellaneous filters.
catalogname char The GSC2.3.2 ID.
catalogNumber int ct Calibration Catalog 0 = gsc2.3.2, 1 = KIC, 2 = APASS, 3 = experimental
catdec double deg Catalog J2000 Declination in degrees
catra double deg Catalog J2000 Right Ascension in degrees
cd1_1 double deg/pix Change in RA---TAN along X axis
cd1_2 double deg/pix Change in RA---TAN along Y axis
cd2_1 double deg/pix Change in DEC--TAN along X axis
cd2_2 double deg/pix Change in DEC--TAN anong Y axis
cdec double deg Search center or plate center Declination in degrees
center int ct Average position: center of the magnet for the plate washer
centerDrift int pix Center drift of solution in pixels
centerSource enum Source of J2000 RA and DEC 'Catalog', 'Logbook','imWCS' or 'WCS'
chn int Kepler satellite CCD channel
class int GSC2.3.2 object type 0 = star 3 = non-star; also synonym for plateClass
classDescription char Description of plate class
class_1 int GSC2.3.2 object type 0 = star 3 = non-star; also synonym for plateClass
class_2 int GSC2.3.2 object type 0 = star 3 = non-star; also synonym for plateClass
clip_median_local double mag Median DASCH magnitude of clipped dataset
clip_ngood int ct Clipped number of points to compute the clipped median DASCH magnitude
clip_rms_local double mag DASCH magnitude RMS of the clipped dataset
col double Kepler satellite CCD column
color double mag magj-magf
colorflag enum no Color correction flag 'linear', 'metropolis' or 'copy'
colorflag_1 enum yes Color correction flag 'linear', 'metropolis' or 'copy'
colorflag_2 enum yes Color correction flag 'linear', 'metropolis' or 'copy'
colorterm double no Color correction term, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm1 double Color correction term spatial bin 1, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm2 double Color correction term spatial bin 2, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm3 double Color correction term spatial bin 3, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm4 double Color correction term spatial bin 4, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm5 double Color correction term spatial bin 5, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm6 double Color correction term spatial bin 6, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm7 double Color correction term spatial bin 7, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm8 double Color correction term spatial bin 8, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm9 double Color correction term spatial bin 9, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm_1 double yes Color correction term, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
colorterm_2 double yes Color correction term, multiply by color and subtract to convert locally calibrated magnitudes to catalog color system
color_1 double mag magj-magf
color_2 double mag magj-magf
comments char Disk event comments
convolutionArea int pix2 Correlation area
convolutionRadius int pix Correlation radius
correlationCount int ct Number of images at the correlation offset from bright stars
correlationLimit int pix WCS fitting correlation limit in pixels. WCStools 'imwcs' input parameter.
count int ct Count of good stars in the summary file or count of mosaics for dxmedian and dymedian
count2 int ct Count of images in a declination band above a particular galactic latitude
count3 int ct Count of images in a declination band
countBad int ct Count of bad measurments (FILTER_AFLAG_LIMITING_MAG flag set)
countGood int ct Count of good measurements (FILTER_AFLAG_LIMITING_MAG flag cear)
countmatch1 int ct number of matching dim objects for search_close
countmatch2 int ct number of matching dim object matches for search_close
countRMSFactor int cutoff signal to noise ratio for multiple exposure correlation
count_limit double ct Minimum significant correlation bin count
count_med double ct Median correlation bin count
count_rms double ct RMS of the correlation bin count
coverage_bin_index int Coverage bin index (approximately 1 square degree of sky)
cra double deg Search center or plate center Right Ascension in degrees
crpix1 double pix X-axis reference pixel
crpix2 double pix Y-axis reference pixel
crval1 double deg X-axis coordinate value
crval2 double deg Y-axis coordinate type
ctype1 char X-axis coordinate type
ctype2 char Y-axis coordinate type
cumulativeCount double ct Normalized cumulative plate count
cumulativeCountBad double ct Normalized cumulative bad observation (FILTER_AFLAG_LIMITING_MAG set)
cumulativeCountGood double ct Normalized cumulative good observation (FILTER_AFLAG_LIMITING_MAG set)
currentVersion int Latest version of the photometry database
damonBlueRms double mag RMS of good lightcurve magnitudes in dnb and dsb plates
Damon_factor double mag difference in clipped DASCH median magnitude for the dnb and dsb series and all non-Damon plates
daschProcessor int ct server on which the photometry pipeline has been executed for this plate.
datatype enum Variable datatype ('char', 'double', 'int', 'short', 'enum', 'set' or 'long')
date char Y-M-D,h:m:s Geocentric exposure date (See ExposureDate for Date)
Date_1 double JD Geocentric Julian date of plate or Heliocentric Julian date of an image
Date_2 double JD Geocentric Julian date of plate or Heliocentric Julian date of an image
ddec double arcsec (image - catalog) declination in arcseconds, catalog corrected for proper motion.
dDeclination double deg Decimal J2000 declination in degrees
ddecMedian double arcsec Median declination error in arcsec per smoothing bin (tnx fitting quality in filterblended)
ddecMedian2 double arcsec Median declination error in arcsec per smoothing bin (final tnx adjustment in recover_points)
ddecRMS double arcsec RMS declination error in arcsec per smoothing bin (tnx fitting quality in filterblended)
ddecRMS2 double arcsec RMS declination error in arcsec per smoothing bin (final tnx adjustment in recover_points)
ddec_1 double arcsec (image - catalog) declination in arcseconds, catalog corrected for proper motion.
ddec_2 double arcsec (image - catalog) declination in arcseconds, catalog corrected for proper motion.
dec double deg Declination in degrees
decimalPlaces int Variable field precision
declination double deg Synonym for dec to avoid MySQL keyword
declinationString char deg Synonym for dec to avoid MySQL keyword
decPixels double pix Offset in declination pixels from the previous exposure
DecPM double mas/yr Declination proper motion in mas/yr
DecPMSigma double mas/yr Declination proper motion error in mas/yr
decrms double deg Standard deviation of lightcurve dec
DecSigmaPM double mas/yr Declination proper motion error in mas/yr
dec_1 double deg Image declination from sextractor
dec_1_1 double deg Image declination from sextractor
dec_1_2 double deg Image declination from sextractor
dec_2 double deg Catalog star declination, precessed to current epoch
dec_2_1 double deg Catalog star declination, precessed to current epoch
dec_2_2 double deg Catalog star declination, precessed to current epoch
Dec_TC double deg Weighted Declination in degrees of the lightcurve points in the selected transient window. Synonym for peakDec
defectFlag int bit SExtractor image is a plate defect
degDrad double deg difference between GSC2.3.2 and Kepler Input Catalog positions in degrees
description char Description of pattern, or telescope
diffPM double mas/yr difference between GSC2.3.2 and Kepler Input Catalog proper motions in mas/yr
diskLocation int Disk raid array number containing the scan tiles or mosaic
diskStatus enum Disk status 'InService', 'Spare', 'Failed' or 'Returned'
dix int x bin index in calculation of dxmedian and dymedian
diy int y bin index in calculation of dxmedian and dymedian
dmag double mag difference in magnitude
dmagcatalog double mag The differences between catalog magnitude and median magnitude in the plates
dmag_iso double mag difference between the lowess-fitted magnitude and catalog magnitude
dmag_iso_1 double mag difference between the lowess-fitted magnitude and catalog magnitude
dmag_iso_2 double mag difference between the lowess-fitted magnitude and catalog magnitude
dmag_local double mag difference between locally corrected calibrated isophotal magnitude and the catalog magnitude
dmag_local_1 double mag difference between locally corrected calibrated isophotal magnitude and the catalog magnitude
dmag_local_2 double mag difference between locally corrected calibrated isophotal magnitude and the catalog magnitude
dnx int ct Number of horizontal bins in calculation of dxmedian and dymedian
dny int ct Number of vertical bins in calculation of dxmedian and dymedian
dra double arcsec (image - catalog) right ascension in arcseconds, catalog corrected for proper motion
drad double arcsec difference between catalog and image position in arcseconds
dradAverage double arcsec The average astrometric mismatch error for a local bin in arcseconds.
dradB double arcsec RMS uncertainty in arcsec for good points, defects, low altitude, uncertain date, and second quality plates
dradRMS2 double arcsec RMS positional error in arcsec per smoothing bin (final tnx adjustment in recover_points)
dradRMS2_1 double arcsec RMS positional error in arcsec per smoothing bin (final tnx adjustment in recover_points)
dradRMS2_2 double arcsec RMS positional error in arcsec per smoothing bin (final tnx adjustment in recover_points)
drad_1 double arcsec difference between catalog and image position in arcseconds
drad_2 double arcsec difference between catalog and image position in arcseconds
drad_bin_count int ct Number of stars used to compute draMedian and ddecMedian (tnx fitting quality in filterblended)
drad_bin_count2 int ct Number of stars used to compute draMedian and ddecMedian (final tnx adjustment in recover_points)
drad_bin_size int ct Number of smoothing bins used to compute draMedian and ddecMedian (tnx fitting quality in filterblended)
drad_bin_size2 int ct Number of smoothing bins used to compute draMedian and ddecMedian (final tnx adjustment in recover_points)
drad_reject_count int ct Stars rejected for high drad (tnx fitting quality in filterblended)
drad_reject_count2 int ct Stars rejected for high drad (final tnx adjustment in recover_points)
draMedian double arcsec Median Right Ascension error in arcsec per smoothing bin (tnx fitting quality in filterblended)
draMedian2 double arcsec Median Right Ascension error in arcsec per smoothing bin (final tnx adjustment in recover_points)
draRMS double arcsec RMS Right Ascension error in arcsec per smoothing bin (tnx fitting quality in filterblended)
draRMS2 double arcsec RMS Right Ascension error in arcsec per smoothing bin (final tnx adjustment in recover_points)
dra_1 double arcsec (image - catalog) right ascension in arcseconds, catalog corrected for proper motion
dra_2 double arcsec (image - catalog) right ascension in arcseconds, catalog corrected for proper motion
dRightAscension double deg J2000 Right ascension in degrees
dual_count_limit1 double ct Minimum significant correlation bin count (parselogs and search_close3)
dual_count_limit2 int ct Minimum significant correlation count actually use (parselogs and search_close3)
dual_count_med1 double ct Median correlation bin count (parselogs and search_close3)
dual_count_rms1 double ct RMS of the correlation bin count (parselogs and search_close3)
dual_maxBinCount1 int ct Maximum correlation bin count (parselogs and search_close3)
dual_maxBinSNR1 double ct maxBinCount divided by count_rms (parselogs and search_close3)
dual_maxCtrMaskArea int ct Maximum mask area with maskCenterFlag set (parselogs and search_close3)
dual_maxMaskArea int ct Maximum mask area (parselogs and search_close3)
dual_minBinCount1 int ct Maximum correlation bin count (parselogs and search_close3)
dual_totalMasksSector int ct total number of masks in a sector (parselogs and search_close3)
dxmedian double pix median x-axis angular difference in pixels between TNX and TAN fits.
dxrms double pix RMS of the x-axis angular difference in pixels between TNX and TAN fits.
dxval double pix x-axis angular difference in pixels between TNX and TAN fits
dymedian double pix median y-axis angular difference in pixels between TNX and TAN fits.
dyrms double pix RMS of the y-axis angular difference in pixels between TNX and TAN fits.
dyval double pix y-axis angular difference in pixels between TNX and TAN fits.
eix int x position of an extinction bin (0-49)
eiy int x position of an extinction bin (0-49)
elevation double m Elevation above sea level in meters
ELLIPTICITY double See sextractor manual. (1 - B_IMAGE/A_IMAGE)
ELLIPTICITY_1 double See sextractor manual. (1 - B_IMAGE/A_IMAGE)
ELLIPTICITY_2 double See sextractor manual. (1 - B_IMAGE/A_IMAGE)
enableFindWCS enum bit Set to 'no' to abort FindWCS or AstronmetryWCS execution; otherwise 'yes'
enx int Number of horizontal bins in an extinction table
eny int Number of vertical bins in an extinction table
epoch double yr Database epoch
equinox double yr Database equinox
ERRA_IMAGE double pix RMS position error along major axis. See sextractor manual
ERRA_WORLD double deg World RMS position error along major axis. See sextractor manual.
ERRB_IMAGE double pix RMS position error along minor axis. See sextractor manual.
ERRB_WORLD double deg World RMS position error along minor axis. See sextractor manual.
errorcolor double yes RMS Error in the color correction term
errorcolor_1 double yes RMS Error in the color correction term
errorcolor_2 double yes RMS Error in the color correction term
errorCount int ct Number of plates in error
errorType set Logbook error type
error_bar_factor double no Error bar factor: min(1.0,the median RMS of the lightcurve divided by the median zero-based RMS of the local calibration RMS of all of the individual points in the lightcurve)
errout double mag Local correction error
ERRTHETA_IMAGE double deg RMS position error along minor axis. See sextractor manual.
ERRTHETA_J2000 double deg J2000 error ellipse pos. angle (east of north)
ERRTHETA_WORLD double deg World RMS position error along major axis. See sextractor manual.
EstDecPM double mas/yr Estimated declination proper motion in mas/yr
EstDecPMRMS double mas/yr Standard Deviation of the estimated declination proper motion in mas/yr
EstRaPM double mas/yr Estimated Right Ascension proper motion in mas/yr
EstRaPMRMS double mas/yr RMS of the estimated Right Ascension proper motion in mas/yr
eventDate char Y-M-D,h:m:s Disk event date
expansionRadius double pix average background calculation bin radius
exposure char min Logbook exposure time, normally in minutes but may be qualified by other units
ExposureDate double JD Geocentric Julian date of plate or Heliocentric Julian date of an image
exposureNumber int ct The zero-based exposure number listed in the logbooks, or -1 if WCS fitting finds more solutions than logbook entries.
exposureNumber_1 int ct The zero-based exposure number listed in the logbooks, or -1 if WCS fitting finds more solutions than logbook entries.
exposureNumber_2 int ct The zero-based exposure number listed in the logbooks, or -1 if WCS fitting finds more solutions than logbook entries.
exposures int ct Number of exposures fitted for this plate
extinction double mag Extinction estimate for an image.
extinction_1 double mag Extinction estimate for an image.
extinction_2 double mag Extinction estimate for an image.
fatalError int terminating condition of the photometry pipeline for this plate.
fatalSolution int ct terminating solutionNumber of the photometry pipeline for this plate
fileExists int 1 if the drad file associated with a plate exists; 0 otherwise
fileName char Filename
fileObsolete int 1 if the drad file associated with a plate is obsolete; 0 otherwise
fileOffset int Byte position offset of the gsc bin into a photometry database file
filingReleaseField int ct Filing location release field (DR1-DR12)
FILTERED_BACKGROUND double ct High-pass filtered background at centroid position
firstPlate int Initial plate number in the range
fittedPlateScale double arcsec/m-3 Average plate scale from available WCS fits in arc seconds per mm
FitWCS set WCS fitting and pipeline status
flag double Plotting flag.
flaggrid int calibration table entry type 0 = too bright, 1 = valid, -1 = too dim
FLAGS int Photometry flag defined by sextractor. See sextractor manual.
flag_MAG_ISO int bit SExtractor image is brighter than the estimated limiting MAG_ISO
flatLinearityJD double JD Julian Date of the last flatfield prior to the scan
FLUXERR_AUTO double ct RMS error for AUTO flux. See sextractor manual.
FLUXERR_ISO double ct RMS error for isophotal flux. See sextractor manual.
FLUX_AUTO double ct Flux within a Kron-like elliptical aperture. See sextractor manual.
FLUX_ISO double ct Isophotal flux. See sextractor manual.
FLUX_ISO_1 double ct Isophotal flux. See sextractor manual.
FLUX_ISO_2 double ct Isophotal flux. See sextractor manual.
FLUX_MAX double ct Peak flux above background. See sextractor manual.
FLUX_MAX_1 double ct Peak flux above background. See sextractor manual.
FLUX_MAX_2 double ct Peak flux above background. See sextractor manual.
focus double mm Focus position in mm
fraction double Fractional extra stars used for WCS fitting. WCStools 'imwcs' input parameter.
FWHM_IMAGE double pix FWHM assuming a gaussian core. See sextractor manual.
FWHM_IMAGE_1 double pix FWHM assuming a gaussian core. See sextractor manual.
FWHM_IMAGE_2 double pix FWHM assuming a gaussian core. See sextractor manual.
FWHM_WORLD double deg FWHM assuming a gaussian core. See sextractor manual.
FWHM_WORLD_1 double deg FWHM assuming a gaussian core. See sextractor manual.
FWHM_WORLD_2 double deg FWHM assuming a gaussian core. See sextractor manual.
galacticbin int ct Galactic Bin Sequence for Scanning
galaxyflag int ct Type of record in the limiting magnitude or nearby object databases
galaxytype char Type of variable (in GCVS) or origin of galaxy reference
galaxyversion int ct Version format of the nearby objects table
gapCount int ct number of correlation gaps in quadrant because of masking
Gclass int GSC2.3.2 object type 0 = star 3 = non-star; also synonym
Gcolor double mag GSC magj-magf
Gdec double deg GSC Declination in degrees
GDecPM double mas/yr GSC Declination proper motion in mas/yr
geoJulianDate double JD Geocentric Julian date of plate
gmag double mag SDSS g magnitude
gmagerr double mag SDSS g magnitude error
GMAGFlag int GSC2.3.2 magnitude origin
gminusrmag double mag sdss g-r color
goodBins int ct number of local smoothing bins without any error flags set
goodDradBins int ct number of local smoothing bins with acceptable positional errors
goodLocalBins int ct number of local smoothing bins with local smoothing correction values
goodMedianBins int ct number of local smoothing bins where the median Stdmag is less than the ((median limiting_mag) + 0.5) magnitudes
goodZoutBins int ct number of local smoothing bins with acceptable local smoothing corrections
Gra double deg GSC Right Ascension in degrees
GRaPM double mas/yr GSC Right Ascension proper motion in mas/yr
GREF char The GSC2.3.2 ID.
griderr double mag lowess fit error in the calibration table
group int The number of each group of unmatched catalog images associated with a single source
groupCount int ct The count of unmatched catalog images associated with a single source
gsc2_id char GSC2 star ID, becomes REF in subsequent tables
GSCBlendFlag int bit If 1, the unmatched image is too close to a bright GSC2.3.2 catalog star; 0 otherwise
gscclass int GSC2.3.2 star class 0 = star; 3 = non-star
gsccolor double mag GSC (JpgMag - FpgMAG) also expressed as ( magj-magf)
gsc_bin_index int A spatial index of approximately 1/4096 degree used to sort images in the input star catalog and the photometry database.
gsc_bin_index_1 int A spatial index of approximately 1/4096 degree used to sort images in the input star catalog and the photometry database.
gsc_bin_index_2 int A spatial index of approximately 1/4096 degree used to sort images in the input star catalog and the photometry database.
GStdmag double mag GSC2.3.2 GSC magj magnitude
GVFlag int bit If nonzero, the GSC catalog star is has an uncertin magnitude.
heightJPEG int pix Length of the y axis of the CameraPC image
hJD double JD Heliocentric Julian Day
hourAngle char HH:MM:SS Logbook hour angle
hours double ct Unrelated to astronomy
imag double mag SDSS i magnitude
imagb int ct magnitude index for magnitude-dependent calibration
imagerr double mag SDSS i magnitude error
iMAG_ISO int Standard sextractor MAG_ISO bin index. There are 220 bins between MAG_ISO = -22 and MAG_ISO = 0.0
imaxmag double mag OGLE I-band maximum magnitude
index int gsc bin offset into a photometry database file. Add to the base index to get gsc_bin_index
inventory enum bit If 'yes' disk found during inventory; otherwise 'no'
ISO0 int pix2 Isophotal area at level 0. See sextractor manual.
ISO0_1 int pix2 Isophotal area at level 0. See sextractor manual.
ISO0_2 int pix2 Isophotal area at level 0. See sextractor manual.
ISO1 int pix2 Isophotal area at level 1. See sextractor manual.
ISO1_1 int pix2 Isophotal area at level 1. See sextractor manual.
ISO1_2 int pix2 Isophotal area at level 1. See sextractor manual.
ISO2 int pix2 Isophotal area at level 2. See sextractor manual.
ISO2_1 int pix2 Isophotal area at level 2. See sextractor manual.
ISO2_2 int pix2 Isophotal area at level 2. See sextractor manual.
ISO3 int pix2 Isophotal area at level 3. See sextractor manual.
ISO3_1 int pix2 Isophotal area at level 3. See sextractor manual.
ISO3_2 int pix2 Isophotal area at level 3. See sextractor manual.
ISO4 int pix2 Isophotal area at level 4. See sextractor manual.
ISO4_1 int pix2 Isophotal area at level 4. See sextractor manual.
ISO4_2 int pix2 Isophotal area at level 4. See sextractor manual.
ISO5 int pix2 Isophotal area at level 5. See sextractor manual.
ISO5_1 int pix2 Isophotal area at level 5. See sextractor manual.
ISO5_2 int pix2 Isophotal area at level 5. See sextractor manual.
ISO6 int pix2 Isophotal area at level 6. See sextractor manual.
ISO6_1 int pix2 Isophotal area at level 6. See sextractor manual.
ISO6_2 int pix2 Isophotal area at level 6. See sextractor manual.
ISO7 int pix2 Isophotal area at level 7. See sextractor manual.
ISO7_1 int pix2 Isophotal area at level 7. See sextractor manual.
ISO7_2 int pix2 Isophotal area at level 7. See sextractor manual.
ISOAREA_IMAGE double pix2 Isophotal area above Analysis threshold. See sextractor manual.
ISOAREA_WORLD double deg2 Isophotal image area in square degrees. See sextractor manual.
ISOAREA_WORLD_1 double deg2 Isophotal image area in square degrees. See sextractor manual.
ISOAREA_WORLD_2 double deg2 Isophotal image area in square degrees. See sextractor manual.
isogrid double mag isophotal magnitude in calibration table
ix int x position of a local calibration bin (0-49)
ixb int ct x index for magnitude-dependent calibration
iy int y position of a local calibration bin (0-49)
iyb int ct y index for magnitude-dependent calibration
jacketJPEG enum bit If 'yes' a plate jacket JPEG image is available, otherwise 'no'
julianDate char JD Julian Date from logbook
Kclass int Kepler object type 0 = star 3 = non-star; also synonym
Kcolor double mag Kepler magj-magf
Kdec double deg Kepler Declination in degrees
KDecPM double mas/yr Kepler Declination proper motion in mas/yr
keepalive enum bit Set to 'no' when aborting a photometry database update, otherwise 'yes'
keplerField enum bit If 'yes', object is on a Kepler CCD chip. Otherwise 'no'
kmagb int ct Number of magnitude bins for magnitude-dependent calib ration
KMAGFlag int Kepler magnitude origin
Kra double deg Kepler Right Ascension in degrees
KRaPM double mas/yr Kepler Right Ascension proper motion in mas/yr
KREF char The Kepler ID.
KRON_RADIUS double Kron apertures in units of A or B. See sextractor manual.
KRON_RADIUS_1 double Kron apertures in units of A or B. See sextractor manual.
KRON_RADIUS_2 double Kron apertures in units of A or B. See sextractor manual.
KStdmag double mag Kepler magj magnitude
KVFlag int bit If nonzero, the Kepler catalog star has an uncertain magnitude.
kxb int ct Number of x bins for magnitude-dependent calibration
kyb int ct Number of y bins for magnitude-dependent calibration
lastPlate int Last plate number in the range.
lat double deg Catalog star galactic latitude
latitude double deg Observatory latitude in degrees
leftMargin int pix Left margin in pixels
lightcurveCount int ct Number of lightcurves on this plate
lightcurverms1 double mag 5-sigma clipped RMS of good lightcurve points
lightcurverms2 double mag 5-sigma clipped RMS of good lightcurve points after detrending (smooth(x,y,0.4,'lowess'))
lightcurverms3 double mag 5-sigma clipped RMS of good lightcurve points after detrending (smooth(y,0.8,'lowess'))
lightcurverms4 double mag 5-sigma clipped RMS of good lightcurve points after detrending (smooth(y,10,'sgolay'))
lightcurverms5 double mag 5-sigma clipped rms of good lightcurve points after detrending (smooth(y,15,'loess'))
limiting_iso double mag Instrumental isophotal magnitude which corresponds to the lowess limiting magnitude
limiting_iso_1 double mag Instrumental isophotal magnitude which corresponds to the lowess limiting magnitude
limiting_iso_2 double mag Instrumental isophotal magnitude which corresponds to the lowess limiting magnitude
limiting_mag double mag lowess limiting magnitude
limiting_mag_1 double mag lowess limiting magnitude
limiting_mag_2 double mag lowess limiting magnitude
limiting_mag_local double mag Locally corrected limiting magnitude
limiting_mag_local_1 double mag Locally corrected limiting magnitude
limiting_mag_local_2 double mag Locally corrected limiting magnitude
line int Line number of the logbook transcription
listName char Filename containing a list of plates
local_bin short Local calibration bin number (ix + (nx * iy))
local_bin_1 short Local calibration bin number (ix + (nx * iy))
local_bin_2 short Local calibration bin number (ix + (nx * iy))
local_bin_index short Local calibration bin number (ix + (nx * iy))
locationId int Telescope location index
logPage char Logbook volume and page
logRemark enum bit If 'Y' a logbook remark is present, otherwise 'N'. Deprecated.
logTimeType char Date type given in the logbook ('EST', 'LST', 'UT', 'SASE' ...)
lon double deg Catalog star galactic longitude
M0 double mag magnitude range for magnitude-dependent calibration
magcal_iso double mag magnitude estimate from lowess fitting
magcal_iso_1 double mag magnitude estimate from lowess fitting
magcal_iso_2 double mag magnitude estimate from lowess fitting
magcal_iso_error double mag - plate overall rms error between the lowess and catalog magnitude.
magcal_iso_rms double mag error in the lowess fitting algorithm
magcal_iso_rms_1 double mag error in the lowess fitting algorithm
magcal_iso_rms_2 double mag error in the lowess fitting algorithm
magcal_local double mag locally corrected magnitude
magcal_local_1 double mag locally corrected magnitude
magcal_local_2 double mag locally corrected magnitude
magcal_local_error double mag (ERROUT in contour_plot_clip_smooth_correct2.f) rms of the needed median magnitude correction
magcal_local_error_1 double mag (ERROUT in contour_plot_clip_smooth_correct2.f) rms of the needed median magnitude correction
magcal_local_error_2 double mag (ERROUT in contour_plot_clip_smooth_correct2.f) rms of the needed median magnitude correction
magcal_local_rms double mag Error of the locally corrected magnitude.
magcal_local_rms_1 double mag Error of the locally corrected magnitude.
magcal_local_rms_2 double mag Error of the locally corrected magnitude.
magcal_magdep double mag magnitude-dependent corrected magnitude
magcal_magdep_1 double mag magnitude-dependent corrected magnitude
magcal_magdep_2 double mag magnitude-dependent corrected magnitude
magcal_magdep_rms double mag Error of the magnitude-dependent correction
magcal_magdep_rms_1 double mag Error of the magnitude-dependent correction
magcal_magdep_rms_2 double mag Error of the magnitude-dependent correction
magcor_local double mag (ZOUT in contour_plot_clip_smooth_correct2.f) median magnitude correction needed in a given plate ragion
magcor_local_1 double mag (ZOUT in contour_plot_clip_smooth_correct2.f) median magnitude correction needed in a given plate ragion
magcor_local_2 double mag (ZOUT in contour_plot_clip_smooth_correct2.f) median magnitude correction needed in a given plate ragion
magcor_local_range double mag Deprecated. Range in magcor_local within a smoothing bin.
magcor_rmsbright double mag Deprecated. magcor_local_rms of the 30 brightest stars in a local smoothing bin.
magcor_rmsdim double mag Deprecated. magcor_local_rms of the 30 dimmest stars in a local smoothing bin.
magdep_bin int Magnitude-dependent calibration bin number (ixb + (kxb*iyb) * (kxb*kyb*imagb))
magdep_bin_1 int Magnitude-dependent calibration bin number (ixb + (kxb*iyb) * (kxb*kyb*imagb))
magdep_bin_2 int Magnitude-dependent calibration bin number (ixb + (kxb*iyb) * (kxb*kyb*imagb))
magdep_bin_edge double mag Dimmest GSC2.3.2 magj minimum magnitude in a magnitude correction bin
magdep_bin_magcor double mag median magnitude magnitude-dependent correction
magdep_bin_median double mag Median GSC2.3.2 magj median magnitude in a magnitude correction bin
magdep_bin_quality double mag Magnitude dependent bin quality measure (magdep_bin_magcor * sqrt(nstar_magdep))/magcal_magdep_rms
magdep_bin_size int ct Bin expansion factor for magnitude-dependent correction
magdiff double mag Magnitude difference between GSC JpgMag and SDSS gmag
MAGERR_APER double mag RMS error vector for fixed aperture mag.
MAGERR_AUTO double mag RMS error for AUTO magnitude
MAGERR_ISO double mag RMS error for isophotal magnitude
magf double mag GSC2 red magnitude.In subsequent tables color = magj - magf
MAGFlag int GSC2.3.2 magnitude origin
MAGFlag_1 int GSC2.3.2 magnitude origin
MAGFlag_2 int GSC2.3.2 magnitude origin
maggrid double mag best lowess fit magnitude in calibration table
magj double mag GSC2 blue magnitude, becomes Stdmag in subsequent tables
magnitudeFile enum bit If 'yes' magnitudes are in a file, if 'no' magnitudes are in a MySQL table.
magvsdeccorr double mag Correlation coef. between lightcurve magnitude and dec
magvslimitingcorr double mag correlation coef. between lightcurve magnitude and limiting magnitude
magvsracorr double mag Correlation coef. between lightcurve magnitude and ra
MAG_APER double mag Fixed aperture magnitude vector. See sextractor manual.
MAG_APER_1 double mag Fixed aperture magnitude vector. See sextractor manual.
MAG_APER_2 double mag Fixed aperture magnitude vector. See sextractor manual.
MAG_AUTO double mag Kron-like elliptical aperture magnitude. See sextractor manual.
MAG_AUTO_1 double mag Kron-like elliptical aperture magnitude. See sextractor manual.
MAG_AUTO_2 double mag Kron-like elliptical aperture magnitude. See sextractor manual.
MAG_ISO double mag See sextractor manual. isophotal magnitude
MAG_ISO_1 double mag See sextractor manual. isophotal magnitude
MAG_ISO_2 double mag See sextractor manual. isophotal magnitude
MAG_ISO_bright double mag MAG_ISO of the brightest matching double images
MAG_ISO_diff double mag MAG_ISO difference between matching double images
MAG_ISO_dim double mag MAG_ISO of the dimmestmatching double images
MAG_ISO_flag int bit MAG_ISO difference between matching double images is within limits if set
MAG_ISO_med double mag See sextractor manual. median isophotal magnitude
MAG_ISO_rms double mag See sextractor manual. rms of the isophotal magnitude
Malmquist_factor double mag clipped median DASCH magnitude of 20 deepest plates - clipped median DASCH magnitude of 20 shallowest plates using good points
Malmquist_factorB double mag clipped median DASCH magnitude of 20 deepest plates - clipped median DASCH magnitude of 20 shallowest plates using good points, defects, low altitude, uncertain date, and second quality plates
maskArea int pix2 Area of the mask
maskAreaRatio double ct Median correlation bin count
maskCenterDistance double ct Median correlation bin count
maskCenterFlag int ct Nonzero if the mask covers the plate center
maskCount int ct Number of masked regions in the plate
maskIndex int ct Index (one-based) of this mask
maskKernelType int Type of convolution kernel found for this plate
maskNumber int Last plate number in the mask pseudo-series
maskSector short multiple exposure mask bin number (ixs + (nxs * iys))
maskXMax int pix Maximum x value of the mask
maskXMin int pix Minimum x value of the mask
maskYMax int pix Maximum Y value of the mask
maskYMin int pix Minimum y value of the mask
matchCount int ct Number of catalog matches on this plate
matchRatio double Fraction of images on this plate which have been matched to a catalog
matchRatio2 double Fraction of searchTableSize matched to secondary stars during multiple exposure correlation
MATCH_NUMBER int The sextractor image NUMBER that a Pickering Wedge ghost image is associated with
maxBinCount int ct Maximum correlation bin count
maxBinSNR double ct maxBinCount divided by count_rms
maxCorrelationIndex int ct Number of pixels in correlation area for search_close
maxDist1 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 1
maxDist2 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 2
maxDist3 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 3
maxDist4 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 4
maxDist5 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 5
maxDist6 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 6
maxDist7 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 7
maxDist8 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 8
maxDist9 double pix Maximum difference in pixels between TNX and TAN fits for spatial_bin 9
maxIx int ct Highest x bin (along width) of the emulsion area
maxIy int ct Highest y bin (along height) of the emulsion area
maxmag int mag Maximum bin magnitude in the summary file.
maxmagdiff double mag maximum magnitude difference between spatial bins for a given MAG_ISO
maxMaskSector int ct total number of masks in a sector (parselogs and search_close3)
maxNoiseConvolution double ct CCD maximum convolved noise ADU squared
maxPeak double ct CCD peak noise in ADU
maxPeakRMS double ct CCD peak noise divided by noiseRMS
maxSpatialBins int Maximum number of annular bins, normally 9
maxTileOverlapCount int ct total number of masks in a sector (parselogs and search_close3)
maxTileSaturation int ct Maximum number of saturated pixels in any tile
max_bright_iso double mag Isophotal magnitude corresponding to the brightest reliable magnitude in a spatial bin.
max_bright_iso_1 double mag Isophotal magnitude corresponding to the brightest reliable magnitude in a spatial bin.
max_bright_iso_2 double mag Isophotal magnitude corresponding to the brightest reliable magnitude in a spatial bin.
max_bright_mag double mag Brightest reliable lowess magnitude in a spatial bin.
max_bright_mag_1 double mag Brightest reliable lowess magnitude in a spatial bin.
max_bright_mag_2 double mag Brightest reliable lowess magnitude in a spatial bin.
max_drad double arcsec Maximum difference between catalog and image position in arcseconds for good points
max_dradB double arcsec Maximum difference between catalog and image position in arcseconds for good points, defects, low altitude, uncertain date, and second quality plates
max_local double mag Dimmest locally corrected magnitude for a lightcurve
max_local2 double mag Second dimmest locally correccted magnitude for a lightcurve
mbinindex int multibinindex for multastrometry
measurementCount int ct Number of photometry measurements on this plate
medDamonBlue double mag Median of good lightcurve magnitudes in dnb and dsb plates
median double mag Median RMS in the summary file
medianMaxPeak double ct CCD peak noise in ADU
medianMaxPeakRMS double ct CCD peak noise in ADU
medianNoiseVectorCount double ct input rows used to calculate noiseMedian and noiseRMS
medianNoiseVectorPoints double ct rows used to calculcate noiseMedian and noiseRMS
medianPeakYInterval double pix CCD position from the last noise peak
medianPeakYIntervalRMS double pix CCD position from the last noise peak
medianStdmag double mag The median magnitude of GSC2.3.2 images rejected by matchstars and filterblended because there are not enough sextractor images to match them with
median_drad double arcsec Median astrometric error in arcseconds within a spatial bin.
median_iso double mag Median lowess magnitude in a lightcurve
median_local double mag Median locally corrected magnitude in a lightcurve
medNonDamonBlue double mag Median of good lightcuve magnitudes excluding dnb and dsb plates
memberCount int ct Number of SExtractor images in a candidate scratch chain
miles double ct Unrelated to astronomy
minIx int ct Lowest x bin (along width) of the emulsion area
minIy int ct Lowest y bin (along height) of the emulsion area
minmag int mag Minimum bin magnitude in the summary file.
minTileOverlapCount int ct total number of masks in a sector (parselogs and search_close3)
minVersionId int Minimum valid versionId for the current catalog calibration.
min_local double mag Brightest locally corrected magnitude in a lightcurve
min_local2 double mag Second brightest locally corrected magnitude in a lightcurve
missingFlag int ct If 1, the plate is marked as missing in the stacks database
model char Disk model from manufacturer
mosaic char Synonym for plate or Plate
mosaicBinning set Binning of available mosaics
mosaicComment char Mosaic comment
mosaicDate char Y-M-D,h:m:s Date mosaic was generated
mosaicHeight int pix Mosaic height in pixels
mosaicNumber int ct Mosaic number for this plate
mosaicWidth int pix Width of this mosaic
multipleFlag int ct If 1, the plate has multiple exposures
n1 int ct Total points read by annular9.m for a lowess fit attempt.
n1_1 int ct Total points read by annular9.m for a lowess fit attempt.
n1_2 int ct Total points read by annular9.m for a lowess fit attempt.
n2 int ct Actual number of points used by annular9.m for a lowess fit attempt.
n2_1 int ct Actual number of points used by annular9.m for a lowess fit attempt.
n2_2 int ct Actual number of points used by annular9.m for a lowess fit attempt.
name char Name of the observing station
naxis1 int pix Length of the x axis of the image in pixels (width)
naxis2 int pix Length of the y axis of the image in pixels (height)
nblend int ct Number of blended lightcurve points
nburst int ct Number of good lightcurve points 0.8 mag above the median value
nburst2 int ct Number of good lightcurve points 0.5 mag above the median value
nburst3 int ct Number of good lightcurve points 0.4 mag above the median value
nburst4 int ct Number of good lightcurve points 3-sigma above the median value
nDamonBlue int ct Number f good lightcurve points in dnb and dsb plates
ndev2 int ct Number of good lightcurve points 2-sigma from the median value
ndev3 int ct Number of good lightcurve points 3-sigma from the median value
ndip int ct Number of good lightcurve points 0.8 mag below the median value
ndip2 int ct Number of good lightcurve points 0.5 mag below the median value
ndip3 int ct Number of good lightcurve points 0.4 mag below the median value
ndip4 int ct Number of good lightcurve points 3-sigma below the median value
nearbyObjectDistance double arcsec distance to closest catalog object of any type to a star
nearbyObjects char Nearby object of interest @ distance in arcsec
nearbyREFflag int ct If 1, a nearby catalog star is within one half the smallest full width half maximum image size and dimmer than the catalog magnitude - 0.5 mag.
nearbyVSX char Nearby VSX object of interest @ distance in arcsec
nearestREF char The ID of a catalog star closest to an unmatched image.
nearestREFarcsec double arcsec The distance in arcsec between an unmatched image and the closest catalog star
nextbound enum bit Next bound ('b') or unbound ('u') logbook in logbook browser linked list
nextpage int Next logbook page number in logbook linked list
nextseries char Next logbook series in logbook linked list
nextvolume int Next logbook volume in logbook linked list
ngood int ct Number of good points in a lightcurve. (AFLAGS = 0 with ra and dec filtering)
ngoodB int ct Number lightcurve points with good points, defects, low altitude, uncertain date, and second quality plates.
nlocal int ct Number of good images in a local correction bin.
nmatch int ct Number of stars matched during WCS fitting. WCStools 'imwcs' result.
nNonDamonBlue int ct Number of good lightcurve points excluding dnb and dsb plates
noiseBufferRatio double ct relative ratio of noise amplitude between quadrants
noiseMedian double ct median CCD ADU error
noiseMinPoints int Number of rows with less than 200 background pixels
noiseRMS double ct CCD ADU noise
noiseVectorCount int ct input rows used to calculate noiseMedian and noiseRMS
noiseVectorPoints int ct rows used to calculcate noiseMedian and noiseRMS
nominalPlateScale double arcsec/m-3 Nominal plate scale in arc seconds per mm
nonDamonBluerms double mag RMS of good lightcurve magnitudes excluding dnb and dsb plates
normadjacentburstdip2 double ct Normalized adjacentburstdip2: Number of good lightcurve points 3-sigma above the median value divided by number of lightcurves with valid adjacentburstdip2 values
normnburst3 double ct Normalized nburst3: Number of good lightcurve points 3-sigma above the median value divided by number of lightcurves with valid nburst3 values
normnburst4 double ct Normalized nburst4: Number of good lightcurve points 3-sigma above the median value divided by number of lightcurves with valid nburst4 values
notes char Logbook transcription comment
nplot int ct Number of default points plotted in a lightcurve.
npoints int ct Total number of points, good and bad, in a lightcurve.
npoints_local int ct (NPOUT in contour_plot_clip_smooth_correct2.f) number of stars used for the median magnitude correction
npoints_local_1 int ct (NPOUT in contour_plot_clip_smooth_correct2.f) number of stars used for the median magnitude correction
npoints_local_2 int ct (NPOUT in contour_plot_clip_smooth_correct2.f) number of stars used for the median magnitude correction
npout int ct number of stars used for the median magnitude correction
Npts_ext int ct Number of points outside the selected points of a transient candidate lightcurve peak. Synonym for peakExtra.
Npts_TC int ct Number of images in a transient candidate lightcurve peak. Synonym for peakCount.
nslope_60 int ct Number points in a lightcurve used to calculate slope_60.
nslope_all int ct Number of points used to calculate slope_all.
nstar0 double ct stars in magnitude bin for magnitude-dependent calibration
nstar_magdep int ct number of bin stars used for the magnitude-dependent correction
NUMBER int Sextractor object number in an image. See sextractor manual.
NUMBER_1 int Sextractor object number of primary double image
NUMBER_2 int Sextractor object number of secondary double image
numfake int ct Number of images not matching GSC2.3.2 objects during defect filtering
numreal int ct Number of images matching GSC2.3.2 objects during defect filtering.
numTiles int ct Number of tiles in the scan pattern
nx int Number of horizontal bins in a local calibration table
nxs int Number of X-axis bins for multiple exposure correlation
ny int Number of verticalbins in a local calibration table
nys int Number of Y-axis bins for multiple exposure correlation
objectsCutoff int ct If fewer sextractor objects than this amount, consider the bin empty
objid long ATLAS refcat2 objid
oldNumber char Original plate number for renamed plates
orientation enum Series plate orientation North Forward or Left, Mirrored (deprecated)
outlierCount int ct Number of outlier images on this plate
outlierRatio double Fraction of images on this plate which are outliers
page int Logbook page number synonym for logPage
passBits int Pass identifier. Unused, only bit 1 GSC2.3.2 pass1 is recognized
pathCount int ct Number of SExtractor images in the longest path of the candidate scratch chain
patrolGroup int ct Patrol filing group (1-4)
patrolPlate int ct Patrol plate flag 0 = wide field telescope (fittedPlateScale less than 350 arcsec/mm), 1 = patrol telescope (fittedPlateScale greater than 350 arcsec/mm)
patternID int Scan pattern
peakArea double ct CCD peak noise area from the center of the CCD array
peakBadColorCount int ct The total number of points with bad or undertain color
peakCount int ct Number of images in a transient candidate lightcurve peak. Synonym for Npts_TC
peakCountNF int ct Number of good lightcurve points inside the selected transient window from narrow field telescopes
peakCountWF int ct Number of good lightcurve points inside the selected transient window from wide field telescopes
peakDays double d Duration of a transient candidate lightcurve peak
peakDec double deg Weighted Declination in degrees of the lightcurve points in the selected transient window. Synonym for Dec_TC
peakDefectCount int ct The number of lightcurve defects in the selected transient window
peakDradRMS double arcsec RMS positional error of selected points of a transient candidate lightcurve peak
peakDradRMS2 double arcsec dradRMS2 pointed added in quadrature for selected points of a transient candidate lightcurve peak
peakDradRMS3 double arcsec RMS positional error referred to peakRA and peakDec of selected points of a transient candidate lightcurve peak
peakEvaluation int Rejection flags (PEAKEVALUATION) for the flare candidate search
peakEventCount int ct The number of peaks in the lightcurve that meet the event criteria
peakEventCount2 int ct The number of peaks in the lightcurve eliminating multiple peaks for each transient
peakEventCount3 int ct The total number of peaks in the lightcurve, valid or now
peakExtra int ct Number of points outside the selected points of a transient candidate lightcurve peak. Synonym for Npts_ext.
peakLimitingPoints int ct The number of plates of coverage at or below peakMag (including the transient points)
peakLimitingYears int ct The number of years of coverage at or below peakMag (including the transient year)
peakLongOutburst int ct Number of multi-year outbursts where the average magnitude/yr increases by 1 mag.
peakMag double mag Brightness of the transient candidate lightcurve peak
peakMaxMag double mag Brightest magnitude of the transient
peakMinMag double mag Dimmest magnitude of the transient
peakMultipleCount int ct The number of lightcurve points in the selected transient window from multiple exposure plates
peakNearbyDistance double arcsec distance to nearby stars that are within 2 magnitudes of the brightest or average magnitude of the transient candidate
peakNoDefectMag double mag Brightest magnitude of the transient, not including defects
peakNumber int ct Order of brightness of the selected peak. The brightest peak is 1, the 10th brightest peak is 10
peakOutside int ct Number of good lightcurve points outside the selected transient window (ngood - peakCount)
peakOutsideNF int ct Number of good lightcurve points outside the selected transient window from narrow field telescopes
peakOutsideWF int ct Number of good lightcurve points outside the selected transient window from wide field telescopes
peakRA double deg Weighted Right Ascension in degrees of the lightcurve points in the selected transient window. Synonym for RA_TC
peakRMS double mag Residual error after linear lightcurve fitting
peakSlope double mag/d Slope of the transient candidate lightcurve after peak
peakSlopeRMS double mag/d Slope uncertainty of the transient candidate lightcurve after peak
peakUpperCount int ct The number of points brighter than (peakMaxMag+peakMinMag)/2
peakYear double yr Year of the transient candidate lightcurve peak
peakYIndex int pix CCD peak noise position from the center of the CCD array
peakYInterval int pix CCD position from the last noise peak
PendingFlag int ct stack processing pending flag yes: plate has not been found; no, plate has been processed.
period double days OGLE orbital period
photFailFlag int ct photometry table insertion failed
phot_bp_mean_mag double mag GSC2.3.2 BPmag magnitude
phot_g_mean_mag double mag GAIA DR2 Gmag magnitude
phot_rp_mean_mag double mag GSC2.3.2 RPMag magnitude
pixDist double pix Difference in pixels between matching double images
Plate char HCO plate designation (series and number within series)
plateClass char Plate class
plateComment char Special scanning status of the plate
plateCount int ct Number of square plates
plateJPEG enum bit If plate JPEG exists, 'yes'; otherwise 'no'
plateNumber int The sequential number assigned to a plate in a given plate series from a single telescope or lens
plateReleaseField int ct Plate Center Release field (DR1-DR12)
plateVersionId int Version Id from the photplates table
plate_ddec double deg declination distance in degrees from the plate center
plate_dist double deg distance in degrees from the plate center
plate_dist_1 double deg distance in degrees from the plate center
plate_dist_2 double deg distance in degrees from the plate center
plate_dra double deg right ascension distance in degrees from the plate center
pmf2 double ct Probability Mass Function of grain noise calculated for the spatial convolution function
pmf2_valid double ct If 1, pmf2 is valid, otherwise shows the negative of the correlationCount where pmf2 becomes invalid
PolyDecRMS double pix RMS declination error in pixel from SCAMP polynomial fitting
PolyRARMS double pix RMS Right Ascension error in pixels from SCAMP polynomial fitting
PolyRefStars int ct Number of reference stars used for SCAMP polynomial fitting
port char Disk drive raid array port
precessionCorrected enum bit If 'yes', precession error has been corrected, otherwise 'no'. Deprecated
prevbound enum bit Previous bound ('b') or unbound ('u') volume in logbook linked list
prevpage int Previous page in the logbook linked list
prevseries char Previous series in the logbook linked list
prevvolume int Previous volume in the logbook linked list
pridepth double mag OGLE depth of primary eclipse
Q0 int ct ADU level in quadrant 0 (upper left)
Q1 int ct ADU level in quadrant 1 (upper right)
Q2 int ct ADU level in quadrant 2 (lower left)
Q3 int ct ADU level in quadrant 3 (lower right)
quadrant int ct CCD quadrant 0 = upper left, 1 = upper right, 2 = lower left, 3 = lower right
quadrantPixelCount int Number of pixels in the CCD quadrant present in this file
qualifier char Source of the plate class information
quality int Plate quality flags
qualitybits char Listing of bits set in plate quality flags
Q_DIFF int ct Row Noise correction
ra double deg Right Ascension in degrees
radius double arcsec Radius of a catlog galaxy in arcsec
raidArray int Raid array number of which the disk is part of
raidDisk char Location in the disk raid array (one-based)
range_iso double mag The magnitude range of the lowess magnitude in a lightcurve
range_local double mag The magnitude range of the locally corrected magnitude in a lightcurve
range_local2 double mag The magnitude range from the second brightest to the second dimmest magnitude in a lightcurve
raPixels double pix Offset in Right Ascension pixels from the previous exposure
RaPM double mas/yr Right Ascension proper motion in mas/yr
RaPMSigma double mas/yr Right Ascension proper motion error in mas/yr
rarms double deg Standard deviation of lightcurve ra
RaSigmaPM double mas/yr Right Ascension proper motion error in mas/yr
ratio double Generic ratio. ratio of goodcumulativeCount to badcumulativeCount+goodcumulativeCount
ratio1 double In defect filtering, the number of images flagged as real divided by the number of images matching the GSC2.3.2 catalog
ratio2 double In defect filtering, the number of images flagged as not real divided by the number of images not matching the GSC2.3.2 catalog
ratio3 double In defect filtering, the ratio of images matching the GSC2.3.2 catalog and the images not matching the GSC2.3.2 catalog.
ra_1 double deg Image Right Ascension from sextractor
ra_1_1 double deg Image Right Ascension from sextractor
ra_1_2 double deg Image Right Ascension from sextractor
ra_2 double deg Catalog star Right Ascension, precessed to plate epoch
ra_2_1 double deg Catalog star Right Ascension, precessed to plate epoch
ra_2_2 double deg Catalog star Right Ascension, precessed to plate epoch
RA_TC double deg Weighted Right Ascension in degrees of the lightcurve points in the selected transient window. Synonym for peakRA.
recordId int Unique MySQL table index
REF char The catalog id
reference int Page reference in History of the Plate Series by Martha Hazen
refmag double mag Synonym for the Stdmag, the GSC2.3.2 magnitude.
refmag_1 double mag Synonym for the Stdmag, the GSC2.3.2 magnitude.
refmag_2 double mag Synonym for the Stdmag, the GSC2.3.2 magnitude.
REFNumber long Star reference designation expressed as an integer
refstars int ct Number of reference stars to use for WCS fitting. WCStools 'imwcs' input parameter.
REF_1 char The GSC2.3.2 ID.
REF_2 char The GSC2.3.2 ID.
rejectFlag int Local calibration bin rejection reason.
reject_count int ct Number of images rejected because of high drad in a spatial bin.
reject_reason int Lightcurve rejection reason.
reject_reason1 int Unmasked reject_reason for a lightcurve image
reject_reason2 int Masked reject_reason for a lightcurve image
releaseField int ct DASCH release field (1-12)
rightAscension char HH:MM:SS J2000 Right Ascension
rightMargin int pix Right margin in pixels
rmag double mag GSC2.3.2 sdss r magnitude
rmagerr double mag SDSS r magnitude error
rms double mag The average locally corrected magnitude rms error for an entire spatial bin.
rmsdradrms2 double deg Standard deviation of lightcurve dradRMS2
rms_1 double mag The average locally corrected magnitude rms error for an entire spatial bin.
rms_2 double mag The average locally corrected magnitude rms error for an entire spatial bin.
rms_factor double mag RMS of the lightcurve divided by the median error; valid variables have a larger rms_factor
rms_local double mag In annular9.m, the RMS of the locally corrected good magnitudes in a lightcurve.
rootFlag int If nonzero, the observation is selected as the root observation of a Transient Candidate
rotation int deg Angle in degrees between original mosaic and mosaic with North up.
row double Kepler satellite CCD row
rowCutoff int ct If greater than equal to this number of empty bins, consider the row empty
scale double arcsec/pix Plate scale in arcsec per pixel
scale1 double arcsec/pix Fitted scale in arcsec per pixel, first coordinate. WCStools 'imwcs' result.
scale2 double arcsec/pix Fitted scale in arcsec per pixel, second coordinate WCStools 'imwcs' result.
scaleDrift double Scale drift during WCS fitting. (1- ratio of scales).
scalex double arcsec/pix x-axis arcseconds per pixel
scaley double arcsec/pix y-axis arcseconds per pixel
scanComment char Scan comment
scanDate char Y-M-D,h:m:s Date scanned
scanExposure double s-3 Scanner exposure time in milliseconds
scanJD double JD Julian Date of the plate scan
scanLinearityJD double JD Julian Date of the last linearity test prior to the scan
scanNumber int Scan number for this plate
scanTime long s Unix seconds
scratchFlag int bit SExtractor image is a plate scratch
sdsscolor double mag SDSS g - r color
searchTableSize int ct Total number of points used for multiple exposure correlation
secdepth double mag OGLE depth of secondary eclipse
selected int bit Entry has been selected.
sensorIndex int ct Magnetic sensor on the plate washer
separation double pix Fitting separation in pixels (obsolete use in arcsec in fithistory). WCStools 'imwcs' result.
sequence int Measurement position within a lightcurve graph
serial char Disk serial number
series char Plate series indicating the telescope or lens used to photograph the plate
seriesId int Index into the plate series table
Sextractor_Blend double ct Number of good points with the sextractor blend or neighbors bits set
SEXTRNUMBER int Synonym for NUMBER to avoid MySQL keyword
SFLAGS int FLAGS bits from sextractor
Sig_TC double arcsec Maximum value of peakDradRMS2 and peakDradRMS3
single_count_limit1 double ct Minimum significant correlation bin count (parselogs and search_close3)
single_count_limit2 int ct Minimum significant correlation count actually used (parselogs and search_close3)
single_count_med1 double ct Median correlation bin count (parselogs and search_close3)
single_count_rms1 double ct RMS of the correlation bin count (parselogs and search_close3)
single_maxBinCount1 int ct Maximum correlation bin count (parselogs and search_close3)
single_maxBinSNR1 double ct maxBinCount divided by count_rms (parselogs and search_close3)
single_maxCtrMaskArea int ct Maximum mask area with maskCenterFlag set (parselogs and search_close3)
single_maxMaskArea int ct Maximum mask area (parselogs and search_close3)
single_totalMasksSector int ct total number of masks in a sector (parselogs and search_close3)
slope_60 double mag-3/yr lightcurve slope for points before 1960
slope_60_err double mag-3/yr lightcurve slope standard deviation for points before 1960
slope_all double mag-3/yr lightcurve slope
slope_all_err double mag-3/yr lightcurve slope standard deviation
smoothedADU double ct smoothedADU at peakYIndex
SMOOTH_BACKGROUND double ct Smoothed background at centroid position (deprecated)
solutionHeader enum bit If 'no', the exposureNumber column is really the solutionNumber; otherwise 'yes'
solutionNumber int The zero-based exposure number in the order found by astrometry.wcs in a multiple exposure image
solutionNumber_1 int The zero-based exposure number in the order found by astrometry.wcs in a multiple exposure image
solutionNumber_2 int The zero-based exposure number in the order found by astrometry.wcs in a multiple exposure image
source enum Source of plates table entry 'Catalog','Logbook', or 'JPEG' expanded with 'logindex','estimate', or 'noknownlog' in logindexnew
spatial_bin short byte annular ring on the plate where the star appears (1 = centermost, 9 = outermost)
spatial_bin_1 short byte annular ring on the plate where the star appears (1 = centermost, 9 = outermost)
spatial_bin_2 short byte annular ring on the plate where the star appears (1 = centermost, 9 = outermost)
speed double ct Unrelated to astronomy
squareBorder enum bit If 'yes' solution used a square region; otherwise 'no'. WCStools 'imwcs' input parameter.
squareCount int ct Number of square emulsion plates
squareCutoff int ct Value of maxIy-minIy. If less than equal the plate is square
src_name char Search query source name
stackFilingBin int ct Plate Stack Filing Location (1-226)
stackLocation char Location in the plate stacks
starCount int ct Number of images in for the gsc bin in a photometry database file
start char HH:MM:SS Logbook time of exposure start
startupJD double JD Julian Date of the scanner software startup
stationIndex int ct Unrelated to astronomy
status enum bit WCS fit result 'succeeded' or 'failed'
std2 double ct Ratio of bin 9 clipped and 3 sigma clipped ADU to the median ADU
Stdmag double mag GSC2.3.2 magj magnitude
Stdmag_1 double mag GSC2.3.2 magj magnitude
Stdmag_2 double mag GSC2.3.2 magj magnitude
stop char HH:MM:SS Logbook time of exposure end
suffix char Suffix for duplicate plate numbers
suffixBase int Suffix base for duplicate plate numbers. Original plateNumber is (plateNumber - suffixBase)
table1MaxRatio double peak/ave correlation ratio for table1 of search_close
table1Peak int ct peak correlation value for table1 of search_close
table1_dimlimit double mag limiting MAG_ISO found by search_close
table2Peak int ct peak correlation value for table2 of search_close
table2Ratio double peak/ave correlation ratio for table2 of search_close
THETA_IMAGE double deg Position angle (CCW/x) determined by sextractor
THETA_J2000 double deg Image angle in degrees East of North. See sextractor manual.
THETA_J2000_1 double deg Image angle in degrees East of North. See sextractor manual.
THETA_J2000_2 double deg Image angle in degrees East of North. See sextractor manual.
THRESHOLD double ct Detection threshold above background. See sextractor manual.
THRESHOLD_1 double ct Detection threshold above background. See sextractor manual.
THRESHOLD_2 double ct Detection threshold above background. See sextractor manual.
tile int Tile position number in the scan pattern. Actual tiles have name Exposure_'tile'.fit
tileJD double JD Julian Date of a flatfield tile
tileMaskType int ct rows relative tile location within a mosaic (see Catalog.h)
timeAccuracy double d Accuracy of logbook time in days
timeSource enum bit Exposure time source, either 'Catalog' or 'Logbook'
timeSpent int s Seconds used for WCS fitting
timeStamp char Y-M-D,h:m:s Time of last write to the database
timeType char Known date type ('EST', 'LST', 'UT', 'SASE' ...)
tolerance int pix WCS fitting tolerance in pixels. WCStools 'imwcs' input parameter.
topMargin int pix Top plate margin in pixels
totalMasks int ct total number of masks in a sector (parselogs and search_close3)
transform set Transform between scan and mosaic 'Flip' and/or 'Mirror'. Used with 'rotation' to match raw tiles with positions in the final mosaic.
turnOffForward int ct Magnetic turn off position in the forward direction on the plate washer
turnOffReverse int ct Magnetic turn off position in the reverse direction on the plate washer
turnOnForward int ct Magnetic turn on position in the forward direction on the plate washer
turnOnReverse int ct Magnetic turn on position in the reverse direction on the plate washer
type char The GSC2.3.2 ID.
u double mm Aerotech stage u position in mm. Slave gantry position
ucd char Unified Content Descriptor
unbound enum bit Logbook volume is bound if 'b' otherwise 'u'
uncertain enum bit If 'yes', there is uncertainty in the location
unit char Variable physical unit
unmatched int ct Number of good (AFLAGS == 0) images unmatched to the catalog for a plate
updateflag enum bit If 'yes' then the star summary data needs to be updated; otherwise 'no'
upper_limit double mag upper limit: limiting_mag - 2*error, where the error is the overall RMS in the annular9.m photom fitting
upper_limit_1 double mag upper limit: limiting_mag - 2*error, where the error is the overall RMS in the annular9.m photom fitting
upper_limit_2 double mag upper limit: limiting_mag - 2*error, where the error is the overall RMS in the annular9.m photom fitting
variableDescription char Description of variable
variableFlag int ct If 1, object is in the AAVSO VSX database
variableName char Variable name in this table
verified enum bit Observatory location is approximate if 'no'; otherwise 'yes';
version char Y-M-D,h:m:s Date logbook transcription was last edited
versionDate char Y-M-D,h:m:s Photometry data version date
versionId int Index into the photometry version table for GSC2.3.2 stars
versionId1 int Index into the photometry version table for Kepler Input Catalog stars
versionId2 int Index into the photometry version table for APASS catalog stars
versionName char Photometry data version name
VFlag int bit If nonzero, the catalog star has an uncertain magnitude.
VFlag_1 int bit If nonzero, the catalog star has an uncertain magnitude.
VFlag_2 int bit If nonzero, the catalog star has an uncertain magnitude.
vmagerr double mag Johnson B magnitude error
vmaxmag double mag OGLE V-band maximum magnitude
volume int Logbook volume numbers
VTmag double mag GSC2.3.2 Tycho2 visual magnitude
wcsnref int ct Number of stars used for WCS matching
WCSSource enum bit Source of the WCS fit, either 'Logbook' or 'imWCS'
width int pix Mosaic width
widthJPEG int pix Length of the x axis of the CameraPC image
wLongitude double deg West Longitude of the observatory in degrees
x double mm Aerotech stage x position in mm
xAutoExposeTable double m-3 Aerotech X-axis Auto-expose position
xbins int Number of horizontal smoothing bins (normally 50)
xcoord double pix Mosaix x-axis of the bin center for magnitude-dependent calibration
xcoord_magdep double pix x-axis center of the magnitude-dependent correction bin
xIndex int pix Correlation offset in pixels
xPixJPEG int pix X-axis brightest selected spot on the CameraPC image
xPos double m-3 Aerotech X position for the tile
xval double pix x-axis position in pixels for calculation of dxmedian and dymedian.
X_IMAGE double pix Mosaic x-axis pixel position of the image. See sextractor manual.
X_IMAGE_1 double pix Mosaic x-axis pixel position of the image. See sextractor manual.
X_IMAGE_2 double pix Mosaic x-axis pixel position of the image. See sextractor manual.
X_WORLD double deg Barycenter position along world x axis. See sextractor manual.
y double mm Aerotech stage y position in mm
yAutoExposeTable double m-3 Aerotech Y-axis Auto-expose position
ybins int Number of vertical smoothing bins (normally 50)
ycoord double pix Mosaic y-axis of the bin center for magnitude-dependent calibration
ycoord_magdep double pix y-axis center of the magntiude-dependent correction bin
year double yr Calendar year of an image
yIndex int pix Correlation offset in pixels
yPixJPEG int pix Y-axis brightest selected spot on the CameraPC image
yPos double m-3 Aerotech Y position for the tile
yrbegin double yr Beginning calendar year of a lightcurve
yrend double yr Ending calendar year of a lightcurve
yval double pix y-axis position in pixels for calculation of dxmedian and dymedian
Y_IMAGE double pix Mosaix y-axis pixel position of the image. See sextractor manual.
Y_IMAGE_1 double pix Mosaix y-axis pixel position of the image. See sextractor manual.
Y_IMAGE_2 double pix Mosaix y-axis pixel position of the image. See sextractor manual.
Y_WORLD double deg barycenter position along world y axis. See sextractor manual.
z double mm Aerotech stage z position in mm Primary gantry position
Zfinal double mag dmag correction for magnitude-dependent calibration
zmag double mag SDSS z magnitude
zmagerr double mag SDSS z magnitude error
zout double mag median magnitude correction needed in a given plate ragion
Zrms1 double mag initial rms before correction for magnitude-dependent calibration
Zrms2 double mag final rms after correction for magnitude-dependent calibration

Notes on Database Variables

Plate Selection

Plates are referenced by a plate series which usually identifies individual telescopes; and a plate number, which usually increases monotonically for every plate exposed at the telescope. Any disk files related to a plate have the extended designation:

{series}{plateNumber}_{mosaicNumber}_{binning}{rotationString}ww{solutionString}{qualifierString}{fileSuffix}

where

  • rotationString is null for zero degrees and r{rotation} for other angles
  • solutionString is null for the first solution and _s{solutionNumber} for successive solutions of a multiple-exposure plate
  • qualifierString is null for the primary GSC2.3.2-calibrated database stream, _{qualifier} for alternate streams such as 'kepler' for photometry data calibrated with the Kepler Input Catalog and 'apass' for data calibrated with the APASS catalog)
  • fileSuffix defines the type of file.

Observatory Location

Telescopes did not necessary remain at one location but were moved between observatories worldwide.

Plate Class

The plate class serves to identify the kind of exposure that was taken and is useful in filtering out plates that may require special techniques for analysis or for selecting plates taken with particular filters or gratings.

Plate Jacket Photographs

Prior to scanning, a photograph was taken of every plate jacket to capture standard plate information and additional notations that may have been made by observers or researchers.

Plate Annotation Photographs

Many researchers made ink annotations on the rear of plates to identify objects. Up until 2023, if such annotations were found prior to scanning, they were photographed and then the annotations were cleaned from the plate. The emulsion side of the plates was never cleaned.

Fitted Plate Scale

Average plate scale from available WCS fits in arc seconds per mm. This column can not be comprehensive because of the following anomalies:

  • The mc series notably has two separate scales because the telescope was refigured after plate 3499. Plates subsequent to 4171 were taken with a curved plate holder.
  • The mb series uses a different telescope between plates 2389 and 2721 inclusive.

These anomalies are currently hard-coded in the database access software.

Exposure Information

Many of the plates have multiple exposures to increase the dynamic range of the emulsion, include calibration fields, or look for short-period brightness changes. For each exposure, the Right Ascension and Declination are calculated for the center of the plate.

Geocentric and Heliocentric Dates

The time of the exposure is expressed as a geocentric date. The corresponding heliocentric date is calculated with reference to the right ascension and declination of the center of the plate. Since some plate series contain plates which cover wide areas of the sky, the heliocentric date may vary significantly from the value at the center of the plate.

If the user specifies a specific location or object in the search page, then the Julian Date result will show the heliocentric date for that object in the search page results table.

For Starbase tables provided by the website, a lower case "date" column header represents a geocentric date and an upper case "Date" column header represents a heliocentric date.

For a discussion of the accuracy of the heliocentric dates in the DASCH lightcuves, see Time Accuracy.

Plate Center Source and Date Source

The initial digitization effort involved typing in the card catalog for the stacks. Approximately 129,000 catalog entries were digitized prior to the availability of initial results from the plate scanner. At this point, the scanner results showed that the Julian Date information available in the card catalog was not of sufficient accuracy for the discovery of objects such as eclipsing binaries. The decision was then made to photograph and digitize the logbooks which were the source of the card catalog data. Information from the card catalog is still designated as Catalog and this information will be eventually replaced by information from the logbooks which are designated by Logbook.

Because the logbook plate centers have a median error of about 0.5 degrees, these logbook plate centers will eventually be replaced with the results of wcs fitting to star catalogs which are designated by imWCS or WCS. For the source of the exposure time, only Catalog and Logbook apply.

Exposure Notes

The digitized card catalog information contains a remarks field which is preserved in the database.

Nearby Objects

This list consists of a series of nearby objects followed by their distance in arcseconds. The list is valid only to within 0.5 degrees of a given search center. The list consists of one of each of the following three object types:

Time Accuracy

There are a number of automated checks possible on the digitized logbook data. The results of these checks is a time accuracy estimate to give researchers an indication of the reliability of the quoted time. Time accuracy is not available for catalog entries. A default value of -1 is used for an unknown time accuracy.

For individual photometric observations, the website uses heliocentric dates calculated with Jessica Mink's WCSTools package. This package provides UT values where valid and extrapolations of UT for earlier dates. Because the package does not provide barycentric dates, the website accuracy can not be better than approximately 2.6 seconds.

For most DASCH plates the time accuracy of a photometric flare can not be better then the exposure time of the plate. A 90 minute patrol exposure has a timeAccuracy of +/- 45 minutes. The median exposure time for all of our logbook entries is 45 minutes. We have only ~180,000 logbook exposures with a timeAccuracy > 1 minute and an exposure time between 1 and 20 minutes.

A detailed description of time algorithms with references in Jessica Mink's WCSTools software. These references appear in the utdt (Compute difference between UT and dynamical time (ET-UT)) subroutine in the dateutil.c module.

The two lightcurves on the left show a test of the correctness of Jessica's algorithms over 100 years. These lightcurves are of the eclipsing variable DV Cep from the DASCH public website. This particular variable was selected from the AAVSO VSX catalog using the "E" eclipsing binary variable type from the GCVS Variability Types list. The lc_ATLAS2_986321200_DV_Cep.gif shows good coverage from 1900 to 1990 because this eclipsing binary is close to the North Galactic Pole where DASCH lightcurves have the largest plate counts. The lc_ATLAS2_986321200_DV_Cep_folded.gif is a folded lightcurve at this star's published period of 1.1619738 days. Here the 7 digit period accuracy means that this binary is accurate to 3 seconds over 90 years. The range of errors in the minimum time of the lightcurve is approximately 90 minutes.

Logbook Information

The database contains images of 663 bound logbook volumes and approximately 500 loose leaf logbooks. Some of the data has been digitized at Harvard and in India, but currently the data is being digitized by volunteers at the American Museum of Natural History in New York City. We appreciate the assistance of Dr Michael Shara, Curator, Dept. of Astrophysics, Holly Klug, Supervisor of Explainer Programs, Dept. of Volunteer Services and their team of volunteers.

All of these photographs are available for browsing.

Exposure Start and Stop Times

Exposure start and stop times were generally recorded in Local Sidereal Time, but in some cases Eastern Standard Time or Universal Time was used. The time type in use can usually be determined from the plate center right ascension and the hour angle. The final reported exposure time in the plate exposure information table is the average of the start and stop times. These times are given to a varying number of significant digits and are used to initialze the time accuracy entry.

Hour Angle

The hour angle was reported not only in the standard sense of increasing time West of the meridian, but sometimes the opposite. Occasionally errors in the sign of the angle can be detected from the context of the rest of the observation.

Logbook Remark

Because comments entered into the logbooks have no defined formats, the typists were instructed to enter either Y or N. Some transcriptions, however, do have transcriptions of the original logbook remark. If this field is blank, the logbook remark was not transcribed or may appear in the notes column.

Logbook Notes

Entries are usually entered at Harvard for certain targets of opportunity. These notes contain the reason for transcription.

Errors Detected by Automated Checks

A number of automatic checks of the logbook data are possible. If one of these checks fail, then the reported time accuracy is reduced accordingly or simply set to 1 day if the actual error magnitude is not obvious. The following definition list shows the error check flags that appear in the database should one of these tests fail. The versions referred to below are used to differentiate new logbook data being entered into the database from previously existing logbook data.

Error Code Description
Discrepancy Discrepancy between India and Cambridge transcriptions. (Deprecated because of exposure number uncertainty for multiple exposures)
E vs W Fixed E Hour angle mistaken for W or vice-versa. Automatically corrected
Bad Date Fixed Bad date fixed from nearby data (Not yet implemented)
Bad Date Bad date which has not been corrected
12H Fixed 12 Hour LST error Fixed
Exposure Times Disagree Exposure Times Disagree
Non-Numeric Exposure Non-numeric exposure time
Daylight Exposure Exposure while sun is up
Bad Volume Number Volume numbers disagree
HA not LST minus RA Error in Hour Angle
Field Length Exceeded Field Length Exceeded
Bad Remark Remark field not "Y" or "N", corrected to "N"
Bad Multiple (OLD) Multiple exposures on different pages - compared with old version
Bad Multiple (NEW) Multiple exposures on different pages - compared with current version
Decreasing plateNumber Plate number not monotonically increasing
Unknown Time Type Unable to determine if time is LST, UT, or EST because longitide is missing
Below Horizon The telescope is apparently pointing below the horizon
Bad Page Error decoding the logbook volume and page
Bad Time Type Best type type is not the expected time type
Unrecognized Time Type Can not decode the time type in the transcription
Unexpected Time Type Transcription time type disagrees with the ranges table
Bad RA Right Ascension less than 0 hours or greater than 24 hours. NOTE: In some cases, the Right Ascension was deliberately written greater than 24 hours. For these cases, 24 hours should be subtracted from the Right Ascension.
Bad Declination Declination less than -90 degrees or greater than +90 degrees. Note: In some cases, the Declination was deliberately written greater than 90 degrees or less than 90 degrees. For these cases, subtract positive declinations from 180 and negative declinations from -180 and add 12H to the hour angle.
Incomplete Julian Day Julian Day fractional part is missing
Julian Day Mismatch Transcribed Julian Day does not match calculated Julian Day
Time Decreasing Exposure time not monotonically increasing

Logbook Digitization

The project to image the logbooks started in early 2006 and was accomplished by George Champine whose report appears below. We regret that George Champine passed away on March 25, 2013.

The digitized logbook photographs are available for browsing.

Determining Optimum Photographic Parameters

The first step of the logbook digitization project was to run a set of experiments to determine the optimum resolution and other photographic parameters. After a number of experiments of creating images of differing resolution, it was determined that a resolution of 1500 by 2000 was more than adequate to represent all of the legibility of the handwritten logbook entries without pixilation for a page size of 10 inches by 15 inches.

Equipment

A copy stand was constructed with three lights. Wood guides were attached to allow quick and accurate positioning of the logbook under the camera. Illumination was 400 watts at 22 inches. A camera-to-logbook distance of 21 inches was used to minimize off-axis distortion and yet obtain adequate image size. Images were captured with a Nikon Coolpix 995 with resolution of three million pixels. The camera was set to: manual mode, monochrome image, image sharpening, and image contrast increase. Automatic exposure was used, which was 1/30 second at F7.9. Auto focus was used to compensate for varying image distance as the logbook pages were turned. A foot-operated shutter release was constructed to speed operation and so that pages could be held flat manually. Each image is a JPG file about 0.6 MB in size.

File Naming

The page image file names that came from the camera were renamed so that the first part of the file name was the name of the logbook, and the last part was the left page number of the double page. This assures that each image can be unambiguously related to its source logbook and page. Since there are both bound and unbound logbooks, a letter "b" designates a bound book and a letter "u" designates an unbound logbook. The logbook cover image is always the first image in the folder and always has file number "-0000", giving a file name for example "rh17b-0000". If there are notes on the inside of the cover, that image always has number "-0001". Each subsequent image is numbered the same as the left page in the image. Thus the image of pages 200-201 in logbook RH17 has file name "rh17b-0200". The Bulk Rename Facility software was used to do the initial renaming, followed by a perl script. The renaming also provided a consistency check to make sure there were no missing pages or duplicated pages.

Folder Naming

The files are stored on the web server in a directory tree.The top level directory is named "LogJpeg". The second level directory is named after the plate series. The third level directory is named with the volume number prefixed by a "b" for bound volumes and "u" for unbound volumes. If the word "new" is included, then the directory contains high-resolution images photographed at the Widener Library.

Research Notebooks

The Widener Library photographed historic research notebooks for transcription. Henrietta Leavitt's notebooks appear under the pseudo-series "hsl" and Annie Jump Cannon's notebooks are appearing under the pseudo-series "ajc".

Page Scanner

Research was carried out to identify a page scanner that would meet project needs for scanning pages in loose leaf logbooks. A Fujitsu FI-5110C was procured and used in limited operation. It provided all features necessary for the project, and was very reliable in operation. Images can be stored as JPGs or PDFs, group file names can be assigned, and images can be numbered with a variable increment. Scan rate is about 15 pages per minute. Tests were run and it was found that a resolution of 150 pixels per inch was adequate to capture all of the legibility information on the pages. To be safe, a scanning resolution of 200 pixels per inch is recommended.

Logbook Digitization Completed

All 813 logbooks had been imaged, generating about 79,470 images using storage of 47 GB.

Scan and Mosaic Information

Scan Number

If a plate is scanned multiple times, the scan number keeps track of individual scans.

Mosaic Number

If a second mosaic must be created from a single scan using a new mosaic algorithm, the mosaic number identifies the algorithm. If available, a new mosaic number is assigned with the corresponding scan number. If not available, new mosaic numbers are assigned from unused scan and mosaic numbers. Afterwards, a new scan number will not be assigned an existing scan or mosaic number.

Scan Date

The scan date is important for identifying early scans which are likely to be of lower quality while the scanner was being tested. Because of the mutually exclusive means of assigning scan and mosaic numbers, the scan date is a better way to determine the order of scanning.

Average Tile ADU

Tiles are individual exposures of the scanner camera which are later combined into a mosaic. Since the scanner camera has a 12 bit CCD readout, the average tile ADU will range from the bias level of 50 ADU to the maximum level of 4095 ADU.

Average and Maximum Tile Saturation

In order to improve the dynamic range for dark plates, the scanner exposure time is automatically adjusted. However, pixels imaging film defects and other areas of missing emulsion will saturate. The saturation count is the number of pixels at 4095 ADU on a per tile basis. Since there are 16M pixels per exposure, this is the upper limit of saturation.

Scan Comment

If the average and maximum tile saturation levels reach preset amounts, the scanner software will automatically enter Saturation Error in this field. The scanner operator is free to add any additional comments describing the state of the plate or the reason for the scan.

Mosaic Comment

If a special issue arises with the creation of the mosaic, a comment will be entered here. Currently, the only comment for some mosaics is Linearity Bug which means that the mosaic should be rejected because of a bug in the early version of the mosaic algorithm.

Mosaic Binning

Normally, the mosaic algorithm generates two mosaics simultaneously. These are the full size mosaics with 1 in this field and a 16 x 16 binned mosaic with 16 in this field. Some other binning factors for early mosaics are also present, but the binning factor must be a power of two.

WCS Fit Solution

This entry indicates whether the stars on a mosaic have been fitted to a standard catalog so that an accurate plate center is known.

Mosaic Rotation

If a WCS fit solution is available, this entry indicates how much the original mosaic must be rotated in a clockwise direction so that North is up.

Photometry Pipeline Information

Plotting Symbols

The following plotting symbols are used. These symbols are defined for the WIP Plotting Software Package. The plotting codes appear in the flags database column listed above.

Symbol Plotting Code Description
Solid circle 17 for a good point
Small solid circle 17.5 for a good point at the edge of the plate
Open circle 22 for a large error point
Small open circle 22.5 for a large error point at the edge of the plate
Arrow pointing down 31 for not found at the indicated limiting magnitude
Small arrow pointing down 31.5 for not found at the edge of the plate
Asterisk 3 for a suspected plate defect
Triangle 7 for a high astrometric error object
Open square 6 for a Pickering Wedge object
Solid square 16 for an object with high or unknown extinction
Arrow pointing up 30 for an object too bright for the photometric algorithm
Diamond 11.5 for a blended object
Cusped square 10.5 for a high local correction object
Letter b 98.5 for an object considered blended by sextractor, but not by the pipeline because of the low threshold we used in running sextractor
Letter c 99.5 for a good object without color correction
Letter q 13.5 for a good object in a plate with: multiple exposures, gratings, red or yellow filters, Pickering Wedge, spectra, fails colorterm metropolis algorithm, or fails colorterm limits.

AFLAGS

This field is a bitmap of photometry pipeline warnings which exclude a magnitude measurement from being included in the summary statistics for a star. Bits 16-18 come from the GSC2.3.2 class field, but only the code for a non-star is currently defined. Bits 20-23 are cases of blended stars. A case B blend is a single image that covers multiple GSC2.3.2 stars. A case C blend is a single GSC2.3.2 star that can be matched to multiple images. A case D blend is multiple GSC2.3.2 stars matching multiple images. Processing of this blend involves subdividing it into smaller groups of matches with the above blend designations: i.e. DA, DB, and DC. The showflags utility can decode the AFLAGS field into its constituent bits. Bits marked with an asterisk below are not used to filter measurements when computing overall lightcurve RMS values on the website home page.

Bit Position Decimal Value Hexadecimal Value Description
6 64 40 *Object has a high background level
7 128 80 *Plate fails quality criterion
8 256 100 Unmatched object on a multiple-exposure plate
9 512 200 *Object has more than 1.1 hour time uncertainty preventing an accurate extinction calculation
10 1024 400 *Object is a multiple exposure blend
11 2048 800 Maximum isophotonic rms exceeded
12 4096 1000 Maximum locally smoothed rms exceeded
13 8192 2000 Star too close to the limiting magnitude
14 16384 4000 Star is in bin 9
15 32768 8000 Object rejected because bin has unknown drad.
16-18 65536 10000 Galaxy (not in GSC 2.3.2)
16-18 131072 20000 Blend (not in GSC 2.3.2)
16-18 196608 30000 Object is Non-star
16-18 262144 40000 Unclassified (not in GSC 2.3.2)
16-18 327680 50000 *Defect (not in GSC 2.3.2)
16-18 458752 70000 Duplicate Star (Added for DASCH project)
19 524288 80000 *Uncertain catalog magnitude (In the APASS catalog all Tycho2 and GSC2.3.2 objects are marked variable to remove them from the magnitude calculation algorithms.)
20 1048576 100000 *Case B - blended
21 2097152 200000 Case C - overlapping Sextractor hits for one GSC star
22 4194304 400000 Case D - mixture of cases B and C
23 8388608 800000 Object has a drad three times the bin drad or is in a bad spatial bin or local bin
24 16777216 1000000 *Object is a Pickering Wedge object
25 33554432 2000000 Object fails the defect filter
26 67108864 4000000 *Copy of the Sextractor blended flag
27 134217728 8000000 Rejected blended object - avoid plotting a limiting magnitude.
28 268435456 10000000 Rejected because of high smoothing correction
29 536870912 20000000 Object is too bright for accurate magnitudes
30 1073741824 40000000 *Object is within 23.5 degrees of horizon

BFLAGS

This field is a bitmap of photometry pipeline conditions which provide additional information concerning how the image was processed. Bits 12-15 are GSC2.3.2 magnitude substitution flags which depend on the setting of bit 23. The showflags utility can decode the BFLAGS field into its constituent bits. Note that bits 12-15 now contain the definitions defined in MAGFlags below.

Bit Position Decimal Value Hexadecimal Value Description
0 1 1 Object has neighbors
1 2 2 Object was blended with another
2 4 4 At least one pixel is saturated
3 8 8 Object is too close to the image boundary
4 16 10 Object aperture data incomplete or corrupted
5 32 20 Object isophotal data incomplete or corrupted
6 64 40 Memory overflow during deblending
7 128 80 Memory overflow during extraction
8 256 100 Magnitude adjusted for a blended star (currently unused)
9 512 200 Object has low drad but it is in a high drad bin (currently unused)
10 1024 400 Object PSF considered saturated (ISO5/ISO4 > 0.7) and ((BACKGROUND+FLUX_MAX) > 7500)
11 2048 800 Magnitude-dependent calibration has been applied.
12 4096 1000 JMag substituted for JpgMag (deprecated)
13 8192 2000 BMag substituted for JpgMag (deprecated)
14 16384 4000 RMag substituted for FpgMag (deprecated)
15 32768 8000 VMag substituted for FpgMag (deprecated)
16 65536 10000 Good star processed by the pipeline
17 131072 20000 Star has been calibrated with the lowess fit
18 262144 40000 Star has been locally calibrated
19 524288 80000 Magnitude has been corrected for extinction
20 1048576 100000 Magnitude calibration not possible because the star is too bright
21 2097152 200000 Bin has a valid color correction
22 4194304 400000 Color correction used the metropolis algorighm
23 8388608 800000 Interpret bits 12-15 as Kepler Input Catalog Source bits;
24 16777216 1000000 Match at end of pipeline.
25 33554432 2000000 High proper motion uncertainty
27 134217728 8000000 Spatial bin fails QUALITY_COLORTERM
28 268435456 10000000 Ra and dec have been adjusted by the bin medians
29 536870912 20000000 This plate has an uncertain Julian Date
30 1073741824 40000000 Catalog position corrected for proper motion

FitWCS

This field is a bitmap of status flags which summarize the state of pipeline processing for the mosaic.

Name Decimal Value Description
Selected 1 Selected for fitting
MikeShawFit 2 Previously fitted by Mike Shaw (deprecated)
Completed 4 Fitting process successful
Copied 8 Fit results copied to head cluster (deprecated)
MultFailedAstrometry 16 Fit results failed AstrometryWCS for next exposure
MultFailedSeparation 32 Fit results failed the separation criteria for the next exposure
MultSucceeded 64 Fit results succeeded for the next exposure
StaleSolution 128 Better astrometry invalidates this solution
StaleExposureNumber 256 The exposure number of this solution has been changed
Wedge 512 This is a Pickering Wedge plate
FilterBlendedTimeout 1024 The filterblended routine timed out
NoAllObjects 2048 The allobjects file for this solution is missing
DuplicateREFCount 4096 This solution shares the same stars with a previous solution
ColortermCrash 8192 The colorterm.m script has crashed and needs to be rerun
InaccuratePV 16384 The SCAMP polynomial fit has significant inaccuracy
NoneFile 32768 The {}_none.db file produced by filter_multiple is present. NOTE: this entry is an internal software flag that does not appear in database files.

MAGFlag

This variable contains flags used in the processing of the GSC2.3.2 catalog. These flags are necessary because the GSC2.3.2 catalog contains magnitudes from multiple source catalogs which used different color filters. Furthermore, there are bugs in the GSC2.3.2 catalog which generate multiple entries for certain bright sources. The goal to put all of the GSC2.3.2 objects on a single color system became possible with the availability of the Kepler Input Catalog. Initially, bits 1-4 were used to identify simple substitutions of JMag or BMag for an unavailable JpgMAG; and RMag or VMag for an unavailable FpgMAG. These definitions are now deprecated. Bits 5-6 are used to eliminate duplicate references to a star and then cleared once this goal has been accomplished. When the Kepler Input Catalog became available, color transformations are now used to put all of the six different populations in the GSC2.3.2 catalog into the reference system of the Kepler Input Catalog and then into the JpgMAG/FpgMAG reference system of the majority of GSC2.3.2 stars. The labels beginning with COLOR identify these six populations. These labels were chosen so as not to create a conflict with the older definitions during pipeline processing. For the Kepler Input Catalog, definitions preceded by KEPLER_CQ designate the source of the Kepler catalog object. This variable is currently unused for the APASS catalog.

Label Bit Decimal Value Hexadecimal Value Description
COLOR_JPGMAG_FPGMAG x 0 0 No substitutions
COLOR_BMAG_FOR_JPGMAG x 3 3 BMag substituted for JpgMag
COLOR_VMAG_FOR_FPGMAG x 4 4 VMag substituted for FpgMag
COLOR_VMAG_BMAG_FOR_JPGMAG_FPGMAG x 5 5 BMag substituted for JpgMag and VMag substituted for FpgMag
COLOR_TYCHO x 6 6 This is a Tycho Source
COLOR_SKYMAP x 7 7 This is a Skymap Source
JMAG_FOR_JPGMAG 1 1 1 JMag substituted for JpgMag (deprecated)
BMAG_FOR_JPGMAG 2 2 2 BMag substituted for JpgMag (deprecated)
RMAG_FOR_FPGMAG 3 4 4 RMag substituted for FpgMag (deprecated)
VMAG_FOR_FPGMAG 4 8 8 VMag substituted for FpgMag (deprecated)
SAME_LOCATION 5 16 10 Rejected because location (RA and DEC) is identical (INTERNAL)
SAME_ENTRY 6 32 20 Rejected because all fields are identical. (INTERNAL)
DUPLICATE_PAIR 7 64 40 Part of a pair of location identical objects. Reject only objects with bit 6 set (INTERNAL)
TYCHO_SOURCE 8 128 80 This is a Tycho source (INTERNAL)
SKYMAP_SOURCE 9 256 100 This is a Skymap source (INTERNAL)
KEPLER_CQ_SCP 0 Kepler Catalog Source, valid when BFLAGS bit 23 is set
KEPLER_CQ_2MASS 1 Kepler Catalog Source, valid when BFLAGS bit 23 is set
KEPLER_CQ_PHOTO 2 Kepler Catalog Source, valid when BFLAGS bit 23 is set
KEPLER_CQ_TYBV 3 Kepler Catalog Source, valid when BFLAGS bit 23 is set
KEPLER_CQ_UNCAL 4 Kepler Catalog Source, valid when BFLAGS bit 23 is set
KEPLER_CQ_NOCAL 5 Kepler Catalog Source, valid when BFLAGS bit 23 is set

quality

On December 11, 2009, Sumin Tang made the following request to eliminate common causes of outliers in her search for interesting variables: Only use the very good points AND(not blends, not defects, not high drad, not within 23.5 degrees of horizon, not in bin 9, not within 0.5 mag of the limiting magnitude, not high iso rms, not high local smoothing rms, not Pickering wedge object) in good blue plates AND(colorterm between -0.5 and 0.25 in the bin, colorflag==2, not dny plates, not dnr plates, not multiple exposures, not Pickering wedge plates) for the calculation of min_local, max_local, range_local, min_local2, max_local2, range_local2, median_local, rms_local, ngood, clip_median_local, clip_rms_local, clip_ngood, median_iso, range_iso in the ID table. For individual images, most of these conditions are handled by selecting only magntiudes with AFLAGS equal to zero. The remaining conditions are handled by this plate quality flag which marks plates that are second quality. Note that the colorterm flag does not appear in the database because this condition is dependent on the annular_bin that the image appears in. The colorterm limits were shifted to -0.067 to 0.283 when the recalibrated GSC2.3.2 catalog was introduced in January, 2010. These new colorterm limits represent the 5% and 95% tails of the new colorterm distribution for blue plates in the M44 region. Colorterm limits were revised again in November, 2012 after over 30,000 plates were scanned and additional calibration catalogs came into use. For the GSC2.3.2 catalog, the colorterm bit is set when the colorterm is outside the -0.097 to 0.410 range; for the Kepler Input Catalog, the range is -0.102 to 0.409; and the APASS calibration, the range is -0.146 to 0.195.

NOTE: in the following table, bits 10 and 11 are not in all data tables provided by the website. These bits appear only in some of the tables provided by the lightcurve access tool and may appear only if specifically requested by the user.

Name Bit Position Decimal Value Description
multiple 0 1 Multiple exposure plate
grating 1 2 Grating plate
color 2 4 Color filter used for plate
colorterm 3 8 Image fails colorterm limits
wedge 4 16 Pickering Wedge plate
spectra 5 32 Spectra plate
saturated 6 64 Saturated Images (ISO5/ISO4 > 0.7) and ((BACKGROUND+FLUX_MAX) > 7500)
nomagdep 7 128 Image not Magnitude-dependent Corrected
patrol 8 256 Wide-Field Patrol Telescopes
nonpatrol 9 512 Narrow Field Telescopes
limiting 10 1024 Show Limiting Magnitudes
undetected 11 2048 Plot plates where the object was not detected
trailed 12 4096 Image trailed (ELLIPTICITY exceeds 0.6)

REF

Catalog reference number. For GSC2.3.2, these numbers begin with N or S, Kepler Input Catalog numbers are prepended with KIC. Tycho2 catalog numbers are prepended with T. APASS DR8 catalog objects are based on Right Ascension and declination: APASS_Jhhmmss.sSddmmss. The ATLAS REFCAT2 has objid values ranging from 1067906928546 to 215982419254548927 which currently can not fit into the REFNumber format described below. For this reason the website uses the record number in the ATLAS REFCAT2 database with the format ATLAS2_<record number> where the record number has a range from 1 to 992637834. However, the lightcurve query will recognize light queries in the format REFCAT2_<objid> and convert these references to sky positions. Finally, unmatched objects have the format DASCH_Jhhmmss.sSddmmss. Since the website dynamically creates positions for unmatched objects, these positions can change with each database update.

REFNumber

In order to reduce disk space, GSC2.3.2, Kepler, APASS, and DASCH designations were replaced with a sixty-four bit integer. To convert from the catalog reference (REF) to the integer (REFNumber), the following rules apply:

Catalog Conversion
Unmatched objects Replace NONEwith 0
GSC2.3.2 Replace N with 11 and S with 12. Be sure to retain any leading zeroes in the numeric part of the GSC2.3.2 identification.
Kepler Input Catalog KIC catalog numbers are prepended with K. For REFNumber, replace K with 2
DASCH DASCH and APASS designations are similar to SDSS designations which are based on Right Ascension and declination. DASCH Jhhmmss.sSddmmss becomes 3hhmmsssSddmmss where S is 1 for positive declination and 2 for negative declination. For example, DASCH J083039.3+140709 becomes 308303931140709. The only difference with APASS designations is that a 4 prefix replaces the 3 prefix.
Tycho2 Catalog numbers are prepended with T. For REFNumber, replace T with 5
ATLAS refcat2 record numbers are prepended with ATLAS2_. For REFNumber, remove ATLAS2_ and replace it with 9.

rejectFlag

These flags are set whenever the collection of images in the local bin do not meet overall quality requirements for the local bin. Such flagged images are not used in statistical analyses.

Name Decimal Value Description
DMAG_REJECT_HIZOUT 1 local correction bin rejected because the local correction is out of range
DMAG_REJECT_MEDIAN 2 local correction bin rejected because median brightness dimmer than the limiting magnitude
DMAG_REJECT_DRAD 4 local correction bin rejected because majority of stars have high drad

reject_reason

The lightcurve plotter compiles summaries of the reasons why individual magntiude measurements should be rejected from consideration. These flags are compiled mostly from AFLAGS with some additional error conditions.

Bit Name Bit Position Decimal Value Hexadecimal Value Description
ERROR 0 1 1 Error processing this Plate
OFFPLATE 1 2 2 Object not on plate
BINFAILURE 2 4 4 No data for this spatial bin
UNDETECTED 3 8 8 Object undetected on this plate
WEDGE 4 16 10 Object is a Pickering wedge
DRAD 5 32 20 Object has high DRAD
DEFECT 6 64 40 Object failed the defect filter
HIZOUT 7 128 80 Object in bad spatial bin
BLEND_NOMATCH 8 256 100 Object in glare of brighter object
BLEND 9 512 200 Object is blended
BIN9 10 1024 400 Object is in bin 9
LOCAL_RMS 11 2048 800 Object has high locally calibrated RMS
LIMITING_MAG 12 4096 1000 Object within 0.75 mag of the limiting magnitude
TOO_BRIGHT 13 8192 2000 Object is too bright
LOW_ALTITUDE 14 16384 4000 Object is too close to the horizon
ISO_RMS 15 32768 8000 Object has high lowess RMS
DRADBIN 16 131072 20000 Object is in a bin with too high RMS drad
COMPLEX_BLEND 17 262144 40000 Object has a case c or d blend
MULTIPLE_BLEND 18 524288 80000 Object is a multiple blend
UNCERTAIN_DATE 19 1048576 100000 Object has an uncertain date for extinction calculation
MULTIPLE_NONE 20 2097152 200000 Unmatched object on a multiple exposure plate
QUALITY 21 4194304 400000 Plate fails quality criterion - see quality
SATURATED 22 8388608 800000 Object is saturated
NOMAGDEP 23 16777216 1000000 Object has no magnituded-dependent correction.
BACKGROUND 24 33554432 2000000 Object has a high background level.

fatalError

These error codes are generated by the CheckProgress routine which is used to ensure completeness when the pipeline is rerun for all plates because of major revisions. Codes less than 100 indicate completed execution. Codes between 99 and 1000 indicate incomplete execution. Codes greater than or equal to 999 are software consistency checks.

Name Decimal Value Description
FATAL_NO_MATCHFILE 1 No match file found
FATAL_NO_ALLOBJECTS 2 recover_points failed
FATAL_ASTROMETRY 3 find_astrometry2 failed
FATAL_ASTROMETRY2 4 find_astrometry2 failed. None file does not exist
FATAL_MAX_SOLUTION 5 Too many solutions
FATAL_ASTROMETRYWCS_FAIL 6 AstrometryWCS failed
FATAL_MULT_FAILED_SEPARATION 7 Second solution is too close to the first
FATAL_MISSING_ALLOBJECTS 8 Allobjects missing for higher order solution
FATAL_NO_FILTER_MULTIPLE 100 filter_multiple did not run
FATAL_NO_ASTROMETRY 200 find_astrometry2 did not run
FATAL_STALE_FILTER_MULTIPLE 300 Latest summary allobjects file not later than individual solution allobject file
FATAL_NO_SUMMARY_ALLOBJECTS 400 Summary allobjects file does not exist
FATAL_NO_WCSHISTORY 500 No AstrometryWCS history available
FATAL_STALE_ALLOBJECTS 600 Allobjects stale for higher order solution - run filter_multiple
FATAL_STALE_ALLOBJECTS2 700 Allobjects stale for higher order solution - run rest of pipeline
FATAL_MISSING_MATCHFILE 800 matchfile missing for higher order solution
FATAL_STALE_MATCHFILE 900 stale matchfile for higher order solution
FATAL_NO_NEXT_MOSAIC 10000 MULTSUCCEEDED without a mosaic
FATAL_UNKNOWN_MOSAIC_STATE 20000 Unknown mosaic state
FATAL_NO_LAST_MOSAIC 30000 Could not get the last mosaic
FATAL_ORPHAN_NEXT_MOSAIC 40000 Have next mosaic but no astromfithistory
FATAL_ORPHAN_NEXT_MOSAIC2 50000 Have next mosaic but no find_astrometry
FATAL_ORPHAN_NEXT_MOSAIC3 60000 Have next mosaic but no none file
FATAL_ORPHAN_LAST_SUCCESS 70000 Have successful next mosaic but no astromfithistory
FATAL_ORPHAN_LAST_SUCCESS2 80000 Have successful next mosaic but no find_astrometry
FATAL_ORPHAN_LAST_SUCCESS3 90000 Have successful next mosaic but no none file
FATAL_ORPHAN_GOOD_ASTROMFITHISTORY 100000 Have good astromfithistory but no find_astrometry
FATAL_ORPHAN_GOOD_ASTROMFITHISTORY2 110000 Have good astromfithistory but no none file
FATAL_ORPHAN_SUCCESS_FILE 120000 Have an astrometry success file, but no none file

magcal_local_rms

This is the estimated error of the locally corrected magnitude measurement. Since adding the spatial bin rms and local correction bin rms in quadrature produces errors which are higher than the rms of the final lightcurve for constant stars, the following procedure recalculates the error based on stars of similar magnitude in the spatial bin.

  1. For each spatial bin, take all of the images which have successfully completed local calibration and sort them by magcal_local, the locally corrected and magnitude-dependent corrected magnitude.
  2. After sorting, divide the images into magnitude bins with 20 stars per bin. Within each bin find the 3-sigma clipped rms of (magcal_local - Stdmag) where Stdmag is the catalog magnitude adjusted by extinction. Since the mean and median values of this rms are expected to be zero, the rms calculation is zero-based rather than based on the mean.
  3. For every image within the spatial bin and magnitude bin, use the rms calculated in step 2. Images dimmer the limiting magnitude will have the rms set to 99.0 and images brighter than the brightest magnitude will use the rms of the brightest magnitude bin.

extinction

Extinction estimate for an image. Because most observations used a single color filter, accurate extinction coefficients are not available. The DASCH project uses the following approximations documented in a private communication from Sumin Tang dated Thu 12/10/09 9:12 PM.

  • blue plates: extinction coefficient = 0.4 - 0.2*(elevation/2300m)
  • yellow plates: extinction coefficient = 0.25 - 0.11*(elevation/2300m)
  • red plates: extinction coefficient = 0.2 - 0.1*(elevation/2300m)

The extinction coefficient is multiplied by the airmass given in atmospheres to provide the extinction in magnitudes for every local bin on each plate. Calibration curves use catalog manitudes adjusted by this extinction value.

Optimization for Transients

The default star matching algorithm attempts to match every observation with a catalog star by recognizing:

  • Astrometric uncertainty.
  • Enlargement of images by saturation.
  • Trailing of images, both deliberate and accidental.
  • Distortion of images.
  • Blending of images with nearby catalog objects.

The transient optimization algorithm gives priority to the value of the SExtractor centroid location over all of the above issues. The search area is divided into 6 arcsec bins and all of the images are placed in these bins. To avoid boundary crossing issues, a parallel sort is performed on a second grid offset by 3 arcsec. Each maximum in this map is assigned to either a catalog star or a DASCH object in the order the number of observations within each bin. All adjacent bins are assigned to the peak bin as long as there are at least three images in these bins. This assignment progresses in the order of decreasing binned observation counts in order to preserve all local count maxima. Where there is a conflict between two objects, the bin contents will be assigned to the closest local maximum.