NAME

nicbias -- correct frames of a multiaccum sequence for the pedestal effect

USAGE

nicbias input slopetry output

PARAMETERS

input =

Multiextension FITS image to correct. This should be a dark-subtracted multiaccum sequence.

slopetry =

Pedestal-corrected initial slope image produced by biasfix.

output =

Multiextension FITS corrected image. This is a multiaccum sequence with a constant subtract from each frame to correct for the pedestal effect.

(save = no)

Save residual frames. This is primarly for debugging purposes.

(resid = )

Residual image name. This is primarily for debugging purposes.

DESCRIPTION

Nicbias takes a dark subtracted multiaccum sequence and an initial guess for the count rates obtained with fullfitbam and corrects each of the multiaccum readouts by a constant amount to correct for the pedestal effect. If there were no pedestal effect, each readout should be the countrate multiplied by the exposure time. In the presence of the pedestal effect, there is an additional non-zero constant added to each frame. To correct for the pedestal effect, nicbias takes each frame, and subtracts the count rate frame scaled by the exposure time for that readout. The median value of each quadrant of the residual image is subtracted from the original image and the result written to the output file.

EXAMPLES

TIME REQUIREMENTS

BUGS

SEE ALSO