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Defect removal

ZAPCOLS allows the user to remove column defects. The program prompts for the first and last column numbers that define the area to be zapped. This area is then replaced by the mean of the two bordering columns. See Appendix C for details of the current chip defects. A negative number terminates the prompts. Routine defect removal should be unnecessary because the sky subtraction algorithm rejects anomalous pixel values in the sky regions, and of course the observer should take care to see the object spectrum does not land on a defect. Luckily there are very few on the chip currently used in FOS.