The Harvard College Observatory Astronomical Plate Stacks

There are over 500,000 glass photographic plates in the Harvard Plate stacks, exposed in both the northern and southern hemispheres between 1885 and 1993. This 100 year coverage is a unique resource for studying temporal variations in the universe. Because there are so many plates, our first plan was to use commercial flatbed scanners instead of the traditional scanning microdensitometer. Because that method was also too slow, we are building a specialized scanner, funded by a grant from the National Science Foundation. Click here for more about the Harvard Plate Collection and its digitization.

Plate Series: Here is a table describing the plates in the collection.
Plate Gallery: Here are images of some of the interesting plates in the collection.
This July 10, 2007 article in The New York Times by George Johnson describes our project. (388,151-byte PDF file)
It was followed by this sometimes-interesting discussion on Slashdot and a July 27, 2007 article in the Harvard Crimson.

Digitizing the Plate Catalogs

The DASCH web site has detailed information about the digitizer and our results so far.
  • A Plates: 17x14-inch plates covering the northern hemisphere from 1893-1910 and the southern hemisphere from 1910 to 1963. [Web search form]

  • B Plates: 8x10-inch plates covering the northern hemisphere from 1885-1889 and the southern hemisphere from 1889 to 1954. [Web search form]

  • MA Plates: Mostly 8x10-inch plates covering the sky visible from the northern hemisphere from 1905 to 1983. Some of the plates are 4x5-inches, and some are 8x12 inches. Only 6,193 of the 11,737 plate which were taken have been catalogued so far. [Web search form]

  • MC Plates: 8x10-inch plates covering the sky visible from the northern hemisphere from 1909 to 1992. Some of the plates are 4x5-inch. Only the 21,983 blue plates have been catalogued so far. [Web search form]

  • MF Plates: 8x10-inch plates covering the sky visible from the southern hemisphere (and the north early on) from 1915 to 1963. Only the 30,090 blue plates have been catalogued so far. [Web search form]

  • R Plates: These wide field 8x10-inch plates were exposed at Radcliffe College from 1937 to 1958. Observing logs for this series were the first imaged as part of this project.

  • RB Plates: These wide field 8x10-inch plates were exposed in Bloemfontein, South Africa from 1928 to 1952. Observing logs for this series have been imaged as part of this project.

  • RH Plates: These wide field 8x10-inch plates were exposed in Cambridge and Harvard, Massachusetts from 1928 to 1963. Observing logs for this series have been imaged as part of this project. [Web search form]

Digitizing the Plates

2001-2002: Commercial scanner testing

2002: M44 Test Project

2003-2006: NSF-funded Digitizer construction
We are currently in the third year of a National Science Foundation grant which is funding the design, construction, and trial use of a digitizer which will rapidly image plates up to 14x17 inches. The project is directed by PI Josh Grindlay and supported by NSF grant AST-0407380, which we gratefully acknowledge. A new website for the project is coming soon.

Papers about the Plate Digitization Project

Presentations about the Plate Digitization Project

Using the Plates

Articles aobut the Plate Scanning Project

Last updated on Tuesday, April 10, 2012 Jessica Mink
Maintained by Jessica Mink |  Privacy  |  Image Use Policy
Last modified on May 30, 2019
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