Deciphering Plate IDs
The following is a guide to understanding the plate IDs for the Mt. Wilson Plate Archive. When the plates were inventoried, it was decided that only information printed on the envelope would be stored in the database. As such, there are many fields that lack information. As an example, searching the PAST database for the observer "Hubble" yields only 55 "hits"! But if one knows that the plate ID suffix "H" stands for Hubble, you can search the plate IDs ending with "H" and get a more respectable 2976 hits. It is hoped the following information will help with such queries. Credit goes to Francois Schweizer for compiling all of this.
Plate IDs 01: Generalities
In the good old days, each telescope, focus, and/or instrument had a unique prefix and the plate identification (ID). These ID prefixes were adhered to by most observers with the introduction of regular plate logs at the telescopes, post World War II (see Sandage reference below). Unfortunately, in the early Mt. Wilson days, they were often not adhered to, and observers routinely had their own way of labeling envelopes. Only the running plate number was pretty universally used.
- Sandage, A., The Hubble Atlas of Galaxies (1961), p. 27
- Arp, H., Atlas of Peculiar Galaxies (1966) (plate listing)
Plate IDs 02: Direct Plates (including Image-Tube Plates)
Plate IDs are of the form X-NNNN-Y, where the prefix X refers to the telescope, the suffix Y refers to the observer, and NNNN is a running number.
|Observatory||Telescope and Prefix||Observers and Suffixes|
Same as Mt. Wilson, plus the following:
|Observers were listed in log books instead of by suffix. These plates tend to have more complete entries in the database.|
|S-1732-H||Plate #1732, 60-inch Mt. Wilson, obtained by Hubble|
|S-330-P||Plate #330, 60-inch Mt. Wilson, obtained by Pease|
|H-1607-H||Plate #1607, 100-inch Mt. Wilson, obtained by Hubble|
|H-2524-M||Plate #2524, 100-inch Mt. Wilson, obtained by van Maanen|
|A-93||Plate #93, taken by Adams (?), probably 60-inch Mt. Wilson|
|PH-20-Bm||Plate #20, Palomar 200-inch, obtained by Baum|
|PS 21122||Plate #21122, Palomar-Schmidt. No observer suffix, but observer field (Arp) is listed in the database.|
|PR 266||Plate #266, Palomar 60-inch. No observer suffix, but observer (Schweizer) is listed in the database.|