• Fitsh homepage

Basic detrending

• Use ficalib and ficombine to detrend the images

• For now just throw away the overscan (-> trim the image to 0..4095;0..4095)

Master bias

ficalib --rewrite-output-name '.fits|_proc.fits' --trim 0:0:4095:4095 -i bias*.fits
ficombine --mode median -o master_bias.fits bias*_proc.fits

Master Dark

Use largest exposure time for master dark

ficalib --rewrite-output-name '.fits|_proc.fits' --input-master-bias master_bias.fits --trim 0:0:4095:4095 -i dark_300s_*.fits
ficombine --mode median -o master_dark.fits dark_30s*_proc.fits

Flats

• Rescale dark (exptime-correction)
• Scale images to common level (post-scale 30000)
• Stack images with reject-median (to get rid of stars in the images IF offsetting between images was done)

ficalib --rewrite-output-name '.fits|_proc.fits' --input-master-bias master_bias.fits --input-master-dark master_dark.fits --exptime-correction --post-scale 30000 --trim 0:0:4095:4095 -i flat_R_*.fits
ficombine --mode rejmed -o master_flat_R.fits flat_R_*_proc.fits

Objects

• Subtract rescaled dark (exptime-correction)

ficalib --rewrite-output-name '.fits|_proc.fits' --input-master-bias master_bias.fits --input-master-dark master_dark.fits --input-master-flat master_flat_R.fits --exptime-correction  --trim 0:0:4095:4095 -i obj_R_*.fits

• Now either run sextractor directly on image or try with grmatch+fitrans+ficombine to stack (see here how to the alignment of the images)