Really bad seeing




Telescope MDM 1.3m
Date 12/15/96
Instrument Nellie CCD
Filter V
Exposure
Time
900
s
Other FWHM = 6.4"

Problem:

This images suffers from ridiculously bad seeing. The FWHM in arcseconds is greater than 6! The full image is about 14' square. The section shown here is about 3.5' square and only ~5 (large) stars and a couple smudges are visible. This is obviously bad seeing because the stars all appear perfectly round (but solid as opposed to out of focus donuts) and have huge FWHM's.

Fix:

Stop observing! Wait for the seeing to improve to something much more reasonable.

Stellar radial plot from this image

Image with good seeing

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Comparison of a field taken in good and bad seeing conditions

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