for the intro #2
Description
terminology: add skyflat / domeflat
add filters, broad bands
review text of pre-reduction:
there are instrumental effects we want to remove, for example:
dark current
unevel illumination
bias level
... and there are callibration frames: images aquired with camera in different conditions
called dark, bias...
The key to understand pre-reduction steps is to not confuse the "frame" and the "effect":
The dark frame is called dark frame because it is taken to caracterize the dark level, but of course it also of course also contains the bias!
The flat frame is taken to , but it also has dark current and bias level!