Dominion Astrophysical Observatory

This page presents World-Wide-Web links to the data archives of the Dominion Astrophysical Observatory (DAO), as well as observing tools for users of the DAO 1.2-m and 1.8-m telescopes.

The DAO archives are operated by the Canadian Astronomy Data Centre (CADC). These consist of two separate collections: the DAO Science Archive and the DAO Spectroscopic Plate Archive.

The DAO Science Archive consists of modern electronic data obtained with the DAO's 1.8-m Plaskett telescope as well as the 1.2-m telescope and McKellar spectrograph. This collection is updated on a daily basis with new data and, as time permits, archival CCD data are also being added.

The DAO spectroscopic plate collection in its entirety consists of over 16,800 high-dispersion spectrograms exposed at the coudé focus of the 1.2-m DAO telescope and McKellar spectrograph between 1962 and 2000, and more than 93,000 secured at the Cassegrain focus of the DAO 1.8-m telescope and spectrograph between 1918 and 1984. The very great majority of those plates is now in the NRC-Herzberg plate archive. Since a programme to digitize them with the modified in-house PDS has only recently commenced (and with limited resources) there is currently a rather modest number of digital files available for download. However, if you have questions about the availability of plates of a target of particular interest you can we encourage you to contact Elizabeth Griffin or David Bohlender at NRC-Herzberg (, so that we can search the collection for plates that may be of interest to your research.

Both archives allow searches by important criteria such as object name, date, and wavelength and presents the results of the search in a tabular format. The CADC's Data Retrieval facility allows archive users to download archival data directly to their own computers.

Proprietary data can also be retrieved, but only by the Principal Investigator (PI) of the science program in question and any colleagues the PI has granted access to that program's data. These users must also register with the CADC in order to enable authorization tests to be made before such proprietary data is accessed. The proprietary period for DAO pixel data is 12 months from the time of the observation. Metadata associated with the pixel data (i.e. the FITS header) is public immediately.

Because of uncertainties in the absolute pointing accuracy of the DAO telescopes, it is recommended that a relatively large search radius (e.g. 5') be used in any DAO archive searches for specific targets.
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