DRnext: Scope

Spatial Coverage

The HCO plate collection covers the entire sky thousands of times over. Plates covering all sky locations have been scanned and processed. When using the daschlab toolkit, data at all sky locations are available.

When accessing DASCH data through the Cannon data access portal, the DR6 spatial restrictions are active: only images and lightcurves associated with galactic latitudes b > 0 are available. The plan is to make all data publicly available as soon as possible. For preview access, either use daschlab, or reach out to the scientific contact named in the footer.

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 has been computed for sources covering the entire sky. In daschlab, all data are available. Through the Cannon data access portal, only sources covered by DR6 (b > 0) are available in self-service format. For preview access to other sources, use daschlab or reach out to the scientific contact named in the footer.