Due to the number of input parameters, lengthy file names, etc, it is not recommended to run any OM chain step by step. Only in special cases, some tasks, as omdetect, ommag, omatt, omsrclistcomb, lcplot, may have to be run so as to fine tune some parameters. In some cases it might be more advantageous to use the interactive omsource or omgsource.
To process task by task a single exposure in image mode, in addition to the house-keeping files listed in Table 10, the following files are needed:
0472_0125910501_SCX00000SUM.SAS - ASCII observation summary file 0472_0125910501_SCX00000TCS.FIT - Spacecraft Time correlation file 0472_0125910501_SCX00000RAS.ASC - Spacecraft Raw Attitude file 0472_0125910501_OMS00400WDX.FIT - Exposure priority window file 0472_0125910501_OMS00400THX.FIT - Exposure tracking history file 0472_0125910501_OMS00400IMI.FIT - Exposure image file to process
These files can be located in the working directory, or in any other one, providing that the environment variable SAS_ODF has been set accordingly. In our examples it is assumed that all necessary files are in the working directory.
The process will be run in the following way.
Although, as said before, no real flat field correction exists for OM, nor it is necessary, the processing requires such a file which can be generated using the task omflatgen as follows.
step0> omflatgen outset=P0125910501OMX000FLAFLD0000.FIT
The output flatfield (primary extension) will be set to unity.
step1> omprep set=0472_0125910501_OMS00400THX.FIT \ nphset=0472_0125910501_OMX00000NPH.FIT \ pehset=0472_0125910501_OMX00000PEH.FIT \ wdxset=0472_0125910501_OMS00400WDX.FIT \ outset=tmp_tracking modeset=3
In case there is no THX file, then set=DUMMYTHX.FIT. omprep will generate a dummy file needed for the rest of the chain, with zero drift in it.
step2> omdrifthist set=tmp_tracking plotfile=P0125910501OMS004TSHPLT0000.ps step3> omthconv thxset=tmp_tracking nphset=0472_0125910501_OMX00000NPH.FIT \ outset=P0125910501OMS004TSTRTS0000.FIT modeset=0 step4> omprep set=0472_0125910501_OMS00400IMI.FIT \ nphset=0472_0125910501_OMX00000NPH.FIT \ pehset=0472_0125910501_OMX00000PEH.FIT \ wdxset=0472_0125910501_OMS00400WDX.FIT \ outset=tmp_image_1 modeset=0 step5> omcosflag set=tmp_image_1 thxset=tmp_tracking \ samplefactor=1 timefactor=1
step6> omflatfield set=tmp_image_1 thxset=tmp_tracking \ inorbitflatset=P0125910501OMX000FLAFLD0000.FIT \ tsflatset=tmp_flat_field outset=tmp_image_2 \ samplefactor=1 step7> ommodmap set=tmp_image_2 mod8product=yes mod8set=tmp_mod8 \ outset=P0125910501OMS004IMAGE_0000.FIT \ nsig=3 nbox=16 mod8correction=1 step8> omdetect set=P0125910501OMS004IMAGE_0000.FIT \ outset=P0125910501_OMS004SWSRLI0000.FIT \ levelimage=level_image regionfile=region_file \ nsigma=2 minsignificance=1 detectextended=yes step9> omqualitymap srclistset=/P0125910501_OMS004SWSRLI0000.FIT \ set=P0125910501OMS004IMAGE_0000.FIT \ outset=P0125910501OMS004IMAGE_0000.FIT \ mode=setqualityimage step10> ommag set=P0125910501_OMS004SWSRLI0000.FIT \ step11> omatt set=P0125910501OMS004IMAGE_0000.FIT \ sourcelistset=P0125910501_OMS004SWSRLI0000.FIT \ ppsoswset=P0125910501OMS004SIMAGE0000.FIT
The detected sources can be overlaid on the OSW by using implot, or ds9.
In the standard automatic SSC pipeline processing, the tmp_image files are reused and thus overwritten. In the task by task processing, they are distinguished so that intermediate stage output can be inspected if desired. In the above example, product names are used where they are similarly used in the SSC pipeline.
The sky images of the multiple exposures corresponding to the default image configuration, as well as images in user defined mode with the same filter, can be combined in a single sky image of the field of view.
Starting with SAS 9, an additional detection can be done on mosaiced images. This will allow us to find fainter sources. The optional parameter processmosaicedimages=yes in omichain has to be used. Please refer to the on-line documentation for more details.
step12> ommosaic imagesets="list of sky images" \ mosaicedset=myfield_in_myfilter.fit
Finally, if multiple images with different filters are processed, the source lists can be combined as follows.
last step> omsrclistcomb sourcelistsets=P0125910501OMS004SWSRLI0000.FIT,..... \ nsigma=3 outset=P0125910501OMS000OBSMLI0000.FIT
where .......... is a continuing list of SWSRLI files.
In case we have multiple exposures with the same filter(s) we can now run (since SAS 10) omvariability