Yerkes Observatory: Yerkes Observatory houses a collection of over 170,000 astronomical photographic plates. Almost all were taken in the twentieth century. Roughly 45% are direct plates, 45% slit spectra and 10% solar images, spectra or spectroheliograms. The majority of the plates were taken using the observatory's 40-inch refractor, the former 24-inch reflector and the wide-field photographic telescope. There are smaller collections taken with other Yerkes telescopes as well as with instruments at the McDonald, Dearborn, Perkins and the University of Illinois Observatories. Of particular interest are the deep photographs taken by E. E. Barnard 1900-1923. No complete inventory of the plate collection yet exists, but some information about the holdings can be found by clicking here.

Spectroscopic Virtual Observatory: The SVO will create a database of archival photographic spectra, most of which have never been digitized before.  The database and its associated operations will constitute the Spectroscopic Virtual Observatory.  The World Spectra Heritage Project is a related effort to gather together and scan spectra, from all over the world, for inclusion in the SVO database and to make the resulting data readily and easily available, much as are other data sets (such as, e.g., IRAS).