Reduction software

An upgraded version of the ``notcam.cl'' IRAF reduction package for NOTCam was released. Improvements include the ``mkflat.cl'' task providing more accurate flats, a few bug-fixes, as well as an optional handling of bad pixels in the ``reduce.cl'' and ``reduce_bs.cl'' tasks.

The non-linearity of NOTCam was modeled pixel-by-pixel with a 3rd order polynomial and the correction coefficients are available as images from the down-loadable NOTCam calibration archive. The correction has been tested on dome-flats as well as standard stars. The non-linearity exceeds 1% just above 20000 ADU, and the correction seems to work well up to levels of 46000 ADU in the raw data (where the non-linearity is  5%). The correction has been tested on dome-flats taken at various dates, as well as on bright standard stars.

A new task ``mklincor.cl'' was made to correct the non-linearity of raw images, and add the corrected image as an extension to the Multi-Extension-Fits file of the raw image. It will be added to a new upgrade of the ``notcam.cl'' IRAF package foreseen for early 2011. It is also planned to include an extra option in the ``reduce.cl'' and ``reduce_bs.cl'' scripts to correct for the optical distortion.