Thursday, April 26, 2012

Problems With an Eclipse at Sunset

I used eyepiece projection to watch the eclipse on 21 July 1990. This eclipse occurred at the time of sunset. I did manage to get one picture of it but the contrast wasn't very good. It was taken at 8:07 pm PDT from the visitor center at Friant Dam and was the last picture on a roll of 35mm film.
I was able to contrast enhanced image of the Sun. The Moon is at the lower right.
It shows the problems that one can run into at sunset and the need for a shade to improve the contrast. You can also see the effect of atmospheric thickness in the lower portion of the image. It's what is known as "valley haze." The lower rim of the Sun appears to be somewhat distorted by atmospheric refraction.

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