***NEW*** Note that with version 18.5.0 one can use multiprocessing to speed up MOPEX tasks. The tasks Overlap, Mosaic, Apex (Multi) and Apex User List (Multi) now allow multiprocessing of some steps. In the GUI, this is set in Initial Setup, Multi-Processing Mode. The options are "on", "off", and "manual". The default is "on" -- this grabs 3/4 of the available processors. Setting "manual" lets the user set the number of processors used. You should see speed-ups of at least 2x.
If using command-line, add these lines at the top of your namelist:
do_multiprocess = on | off | manual default = off
ncpu_multiprocess = 1 default = 1
If "manual" is set, set ncpu_multiprocess to the number of processors to use.
4.3.2 Overlap Modules: Overlap Settings
Command Line Equivalent: N/A
Default Output Directory: N/A
Depends On: Initial Settings
Important Notes: None
PURPOSE
To set the input parameters specific to the Overlap pipeline.
INPUT
Pixel by Size: Check this to set the output pixel size in degrees. Some default output pixel sizes are given in the example templates.
Pixel Size X (deg): Set the X-size of the output pixels in degrees. The pixel size in the X-direction is quoted as a negative value to comply with convention. A positive value will generate an error message.
Pixel Size Y (deg): Set the Y-size of the output pixels in degrees.
Pixel By Ratio: Check this to set the output pixel size by ratio of the input pixel to the output pixel, i.e. to make the output pixels half the size of the input pixels (over-sample the mosaic), set the values of Pixel Ratio X(Y) = 2. The ratio is taken after correction for geometric distortion.
Pixel Ratio X: Set the pixel ratio in the X-direction.
Pixel Ratio Y: Set the pixel ratio in the Y-direction.
Delete Intermediate Files: Check this to delete all of the intermediate files created by the Overlap pipeline. This leaves only the input files and the files created by the final module. This is useful for saving disk space once you are satisfied with your reduction setup. Note that MOPEX will prompt you with a pop-up box at the end of the flow, to be sure that you meant to select this irreversible option.
Use Refined Pointing: Check this to use the alternate FITS pointing keywords created by the offline pointing refinement script (pointing_refine.pl). Do not switch this on unless you have manually run pointing refinement outside of the normal BCD pipeline products. Most users will never use this option, as pointing refinement is not recommended for Spitzer data. If you believe that there is a problem with the pointing of your data with respect to e.g. the 2MASS catalog, please email the Spitzer Helpdesk for assistance.
Apply Zodiacal Subtraction: Check this to subtract the Zodiacal light from the input BCDs before running the background matching. The estimated Zodiacal light level is taken from the FITS header keyword ZODY_EST. In the case of IRAC images, Overlap also reads the keyword SKYDRKZB, which is the estimate of Zodiacal light in the IRAC skydark. For IRAC images, the value subtracted is ZODY_EST - SKYDRKZB.
Save Zodiacal Subtracted Images: Check this to save the Zodiacal light-subtracted BCDs.
COMMAND LINE INPUT
The following parameters are set in the Global Parameters part of the namelist. Note that if both MOSAIC_PIXEL_SIZE_X(Y) and MOSAIC_PIXEL_RATIO_X(Y) are both set, the former takes precedence and will override the latter.
MOSAIC_PIXEL_SIZE_X = -0.00033889
MOSAIC_PIXEL_SIZE_Y = 0.00033889
MOSAIC_PIXEL_RATIO_X = 1
MOSAIC_PIXEL_RATIO_Y = 1
delete_intermediate_files = 0
USE_REFINED_POINTING = 0
apply_zodiacal_correction = 0
save_zodiacal_subtracted_images = 0
OUTPUT
If the Save Zodiacal Subtracted Images option is checked, the corrected files are saved in the <output_dir>/Zod_Sub directory.
DISCUSSION
Overlap Settings sets up all of the input options that are specific to the Overlap pipeline. Some of them may be repeated in the Mosaic Settings, so you should be aware that you may need to match some settings (e.g. Pixel Ratio) between the pipelines.
