MOPEX User's Guide - IRSA

Chapter 3. MOPEX Input
MOPEX User’s Guide
MOPEX requires three main input types in order to carry out any processsing. The following
section provides more information about each of the input types:
1. Input FITS images. These include the data images, the associated mask and uncertainty
files and any calibration files.
2. Text files listing the input images. These should be in ASCII format.
3. The namelist. This is a parameter file specifying all of the input parameters to be used by
MOPEX. This is usually built up from within the GUI, either from an empty flow, or by
modifying existing templates, but you can also read in a previously-saved namelist from
an ASCII file.
3.1 MOPEX Input Images
Images input into MOPEX do not have to be Spitzer data, but they do have to be in FITS format,
with the standard FITS and WCS keywords. This software cannot process data cubes. The
following keywords are required in the headers of the input files for the software to work:
BITPIX, NAXIS, NAXIS1, NAXIS2, CRVAL1, CRVAL2, CRPIX1, CRPIX2, CTYPE1,
CTYPE2. CD-Matrix elements or/and CDELT1, CDELT2, CROTA2 should be also present.
All of the projections in the WCS library are implemented, including "SIN", "TAN", "ZEA"
(Lambert's zenith equal-area), "ARC" (zenith equidistant), and "STR" (stereographic). "TAN" is
the default.
There are no practical restrictions on the size of the area of sky covered by the set of images in
order to be processed by the mosaicker. The only nominal restriction is that the set of images
should only cover one hemisphere (a solid angle < 2π Sr).
3.1.1 Spitzer Image Files
When you download your Spitzer data from the archive, you will find that there are many
different files that are associated with each observation. Moreover, the filenames differ depending
on the instruments. There are three types of image file that are commonly used as input into
MOPEX Input 19
MOPEX Input Images