Spatial Coverage

The HCO plate collection covers the entire sky thousands of times over. Plates covering all sky locations have been scanned and processed. Data at all sky locations are available.

Temporal Coverage

To first order, the HCO collection and the DASCH data span the entire history of astronomical photography: from the invention of the technique (1880’s) to the triumph of the CCD (1990’s). Data across this entire range are available.

Collection Coverage

Approximately 430,000 plates in the HCO Plate Stacks collection have been digitized. This represents virtually all of the plates that are believed to be viable for photometric analysis.

The remaining plates include spectrum observations, ones made with Pickering wedges or other items in the optical path, severely damaged plates, lost plates, and so on.

Photometry

Photometry has been computed for sources covering the entire sky, and data for all sky positions are publicly available.