Darks and Dark Flats

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Affiliation
American Association of Variable Star Observers (AAVSO)
Sat, 02/14/2015 - 14:19

What is the difference between a DarkFrame and a Flat Dark?

Affiliation
American Association of Variable Star Observers (AAVSO)
flat-darks

A "flat dark" is a dark frame that has the same exposure time and temperature as the flat-field image.  Often flats are taken at much shorter exposure times than your science frames, and so you might use special dark frames for subtraction.  A regular "dark frame" just matches the science frame - it may be a stack of darks with the same exposure time, or it may be a longer exposure stack that is scaled to match the exposure time of the science images.

Arne