Introduction

Fast, on-line image correction and calibration is the key for the success of the ROTSE-III program. In this chapter I describe our current strategy for creating calibration frames (darks and flats), as well as using these calibration images quickly in an on-line pipeline. A full discussion of the online analysis pipeline, is in Chapter 8.

The ROTSE-III system runs with an unfiltered, thinned CCD. This, combined with the wide-field, creates difficulties in getting good quality flat-field images. Not only do we have to deal with the vignetting from the wide-field and the pixel-to-pixel quantum efficiency variations,^7.1 strong night-sky emission lines create an unpleasant interference fringe pattern in the images. The final plan for obtaining flat-field images will most likely change from the process currently described in this chapter.

For use in the automated pipeline, calibration files are put in the directory:

/rotse/data/pipeline/cal/