Quote:
Originally Posted by leon
Hi Guys, well I'm probably going to ask the dumbest question of all time and should probably know the answer, but, do you use the light box in the day or at night, never used one, or seen one for that matter other than on IIS. 
Leon  |
Hi Leon
'Aint no such thing as a dumb question. I guess the 2 most important factors in taking “Flat Field” images with a light box are:
- The field “seen” by the ‘scope/ccd camera must be flat (evenly illuminated) and,
- The configuration (rotation, focus) of the sensor and telescope must not change between taking your light frames and the flat field frames.
So, I usually take my flats at the end of an imaging session, usually in twilight so I’m not wasting any imaging time.
If you do say, rotate the CCD camera in the focuser, or re-focus the image after taking your light frames, then any vignetting and dust shadows will not line up between the light frames and flat field frames.
Cheers
Dennis