Don Westergren's Deep Sky Page


Welcome to my Deep Sky Web Site. It's purpose is to share information and knowledge I have gained in the fields of Amateur Astronomy and Astro Photography. In 2002 I decided to test the available films to realistic exposures I was using for my own astrophotography. At the time, there were examples of testing film for reciprocity losses up to 2 minute exposures. However I felt these were not representative for longer exposures. I tested many films out to 4-1/2 hour exposures under controlled conditions and published that data on this web site.

Shortly after completing these film tests, both Kodak and Fuji stopped making the "good" astro films and changed to color negative films with little sensitivity to H-Alpha (red) nebula light. With the loss of the good films, and the availability of digital cameras at affordable costs, the interest in film astrophotography has waned. The film test data has not been updated since 2004, however there is still some legacy interest in the data in 2008, even though most of the films are now out of date.

Click the link below for a PDF file with all the film test data and descriptions. The file is 1.2 MB

Comments and questions are always welcome

Updated August 13, 2008


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