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AAVSO Eggen Card Project

Olin Eggen was an astronomer, a photometrist; he measured the brightness of stars. But being of the last generation, his data was not recorded on a computer. He used 3x5 index cards. Lots of them. The goal of this project is to make the data he recorded in the last century available to researchers today. 

The AAVSO acquired the cards of his observations back in 2007 and introduced the project in a posting that you should review at . All the cards were scanned into PDF's. We've gone the second step and put these card images into a database. 

The third step of the project is to have someone examine each card and identify the star(s) that were observed on each card. When we've done this for all the cards a researcher will be able to key in a star reference and be able to summon up to his screen all of the relevant cards. To be clear: we are not interpreting the data on the card, only looking for the star reference.

There are 108,000 cards that need to be examined. These cards are grouped into 2,216 PDF's, which are grouped into 258 bundles which are grouped into 64 boxes.  So, a card can be identified by its Box/Bundle/PDF/Page address. On average, there are 48 cards per PDF and 8 PDF's per bundle.

Happily, in 2016 this third phase of the project was completed. Through the effort of many all of the cards have been examined and indexed. There are probably some errors and missed cards, but I'm confident that over 90% of the cards with useful photometry are reachable by their star name.

So we are now in the fourth phase of the project, extracting the photometry from these cards and transferring it to modern databases and using it for research. Follow the link in the sidebar to see how to search the cards. Jack Crast has taken the lead here with tools and instructions on how to interpret the cards and extract the photometry. See his website.


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