1. Introduction to Photometry with Mosaic



We have adopted the philosphy that since they are eight separate CCDs, each with its own set of color terms and PSF, it only makes sense to do the photometry chip-by-chip, dither-by-dither. Sure it's 40 times more work than doing the photometry on a single stacked image, but it is the only way we've found to be able to do 1% work.

In order to produce photometry this century, however, we've written a number of scripts to make our lives easier. This collection is known as "Autophot" and "Autocalib". We are making the source code available in the following pages; just give us a warm acknowledgement in any publications.

However, for all of this to work, the fortran executibles have to be declared as "foreign tasks" in your login.cl, as well as the iraf routines defined as either parameter or non-parameter tasks. All this goes into our loginuser.cl , which is invoked when you start up IRAF.