by Buell T. Jannuzi and Chris Greer

This is Version (6.2) (October 9, 2000) -- is now out of date, but is still available on the web for those that are actively working on data sets using this version as their guide. I expect to remove it from the Web at the end of 2001. Send comments/corrections to Buell Jannuzi at jannuzi@noao.edu.

NOAO's two MOSAIC cameras produce very large images at a significant rate, resulting in a large, but manageable, data reduction challenge. In these Web pages we describe the current proceedures for the reduction and calibration of the NOAO Deep Wide-field Survey (NDWFS) Mosaic images. These notes were generated by Buell Jannuzi and Chris Greer based on what the NDWFS has learned from reducing MOSAIC images using the IRAF tasks written by Frank Valdes, Lindsey Davis, Doug Tody, and the rest of the IRAF group. Additional scripts by Ed Ajhar, Ian Dell'Antonio, Arjun Dey, Marc Dickinson, Chris Greer, Buell Jannuzi, and James Rhoads have been used during various stages of the our development of these reduction procedures. Additional input on techniques/methods/steps in the reduction path were contributed or adopted by BTJ from the work of Ed Ajhar, Tod Lauer, and Phil Massey. Very helpful information about the behavior of the two MOSAIC cameras has also been provided by Taft Armandroff, George Jacoby, Rich Reed, Tom Wolfe, Roger Smith, Steve Heathcote, and Alistair Walker. Users of earlier versions of these notes (including Heather Groch, Dan Macintosh and Steve Dawson) have helped identify sections that need improvement -- some of these have been addressed. Hopefully these notes will continue to improve as we all learn to improve our reductions of the MOSAIC images.

These notes are not a replacement for the help that can be found in the notes by Frank Valdes about the mscred reduction package in IRAF. Frank's notes can be found by typing mscguide at the cl> prompt in IRAF. Further, these pages do not attempt to justify why we apply the basic reduction steps discussed here. For such discussions see the excellent guide by Phil Massey, A User's Guide to CCD Reductions with IRAF and the NOAO CCD Mosaic Imager User Manual . These notes can be used as one practical example of using the available tools in IRAF to apply basic calibrations to a set of MOSAIC images. They are not intended to be an exhaustive listing of all necessary reductions you might have to make for your own particular science application.

Note that occasionally you will see links starting with NDWFS. These point to NOAO Deep Wide-Field Survey pages that are very specific to our survey and unlikely to be of general interest.