MOPEX Online Manual
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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).
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: Basic Calibrated Data (BCD) images, the associated uncertainty image, and the associated bad pixel mask.| Instrument | Default BCD | BCD Uncertainties | BCD Status Mask |
| IRAC | bcd.fits | bunc.fits | bimsk.fits |
| IRS-16 | bcdb.fits | uncb.fits | mskb.fits |
| IRS-22 | bcdr.fits | uncr.fits | mskr.fits |
| MIPS-24 | bcd.fits | bunc.fits | bbmsk.fits |
| MIPS-Ge (70 & 160) |
bcd.fits | bunc.fits | bmask.fits |
Additional Mask Files
In addition to the Status Mask Files that come with your Spitzer data (which flag the temporary bad pixels in each frame) there are two other types of mask file that can be input into MOPEX. The first is the mask of permanently damaged pixels (PMask). The PMasks for each instrument are updated every few months, depending on solar activity. They can be found in the <mopex_dir>/cal directory, or on the Spitzer website. The applicable PMask depends on the observation date of your data - check your fits headers for the keyword DATE_OBS (not DATE, which is the date the file was written). See the pmasks.README file in the PMasks directory for the date range for which each PMask should be applied.
The final set of images that can be input into MOPEX are RMask files, which are masks of pixels rejected as outliers in each frame. The RMasks are generally created by MOPEX during the image processing (see Outlier Detection and the Mosaic RMask module), but there is the option to include them as input in subsequent runs of the pipeline. They can also be specified as input into APEX Multiframe to ensure that outlier-rejected pixels are not used when running the PRF fitting on the individual BCDs.
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