Glass Plates

Yerkes Observatory is home to more than 175,000 astronomical glass plates, dating from 1897 to the 1990s.

Part of the University of Chicago collection, the majority of the plates are in situ at Yerkes Observatory. Collection strengths include sky surveys, spectra, and objective prism plates. Plates are organized by plate number and series. Generally, each series is associated with a single telescope, although some series include plates from multiple telescopes and even multiple locations. For more information about any of the resources listed below, please contact the Yerkes Project Team.

Currently a small percentage of plates are digitized, but research is encouraged! There are multiple ways to search:

• LUNA
• Knowledge@UChicago
• By plate series
• By logbook

In LUNA

This is a good place to see what is digitized and available. The material in LUNA is a visual inventory of scanned plates, and can be scanned here.

It is also possible to search directly in the LUNA site, which allows for more specific keyword searches as well as faceted searches by date, type of plate, observer, and right ascension.

In Knowledge@UChicago

Tiff and FITS files and catalogs associated with plates utilized in publications and research are stored in the Knowledge@UChicago repository.

By plate series

Plate series are categories of plates and are the way the plates are organized in the vault. Series names can be related to the telescope, observation type, observer, or other descriptor. Series are currently tracked in spreadsheets, and searching by series is a good way to look for plates related to a general research focus, telescope type, date of observation, or declination.

The best way to open these .csv files and maintain formatting is to download them to your computer, then use the File> Open method in your spreadsheet program of choice (Excel, Numbers, Google Sheets, etc.) Double-clicking to open will work, but formatting of special characters may display incorrectly.

Please note: series inventories are always being updated. As series are cleaned and prepped for public use, we will continue to make them available. If you do not see a series that you believe to be part of the Yerkes collection or have any other questions about the plates, please contact the Yerkes Project Team. We are happy to help!

By logbook

This is a good way to search for information about a particular plate or a group of plates and find notes by astronomer and observers. If you have plate numbers, it is likely the most efficient way to find information about a particular plate as well as other plates "nearby," like searching the stacks in a library. Logbooks can also help you identify particular plates of interest in the collection, and often include tangential information like developer formulas and calculations.

Support for this project comes from the National Science Foundation (Grant AST-2101781), University of Chicago College Innovation Fund, John Crerar Foundation, Kathleen and Howard Zar Science Library Fund, Institute on the Formation of Knowledge, and Yerkes Future Foundation.