1.1 HOW-TO Obtain PSF Information of Science Images

A simple recipe is available to make several plots of SExtractor parameters relevant to the PSF. The recipe is $AWEPIPE/astro/filerecipes/PSF_Anistropy.py and is used as follows:

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       CATEGORY : Health check

       PURPOSE : Detect PSF Anisotropy

       FULFILLS : Requirement 554 (Category III)

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       This recipe makes 5 plots of SExtractor parameters:
       1) Bars of length FWHM_IMAGE (times a scale factor) and angle w.r.t.
          x-axis Theta. Average FWHM_IMAGE and THETA are evaluated per area
          in a grid of Xpos/Ypos.
       2) MAG_ISO vs. FLUX_RADIUS (half-light radius)
       3) FWHM_IMAGE vs. THETA (position angle)
       4) FWHM_IMAGE vs. Xpos-CRPIX1
       5) FWHM_IMAGE vs. Ypos-CRPIX2

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       Mandatory inputs :

           -l : list of input split raw or processed science images

       Configuration parameters (min - [default] - max) :

           -s  : switch to not run SExtractor (if catalogs already exist)
           -d  : SExtractor detection threshold
                 range: 0.0 - [10.0] - 100.0
           -f  : maximum FLAG of sources
                 range: 0 - [0] - 255
           -m  : maximum FLUX_MAX of sources
                 range: 0 - [60000] - 70000
           -r  : minimum FLUX_RADIUS of sources
                 range: 0.0 - [0.0] - 50.0
           -rm : maximum FLUX_RADIUS of sources
                 range: 0.0 - [50.0] - 50.0

       Switches :

           -in : interactive mode (if omitted a postscript file is created)

       Example of use :

           awe PSF_Anisotropy.py -l image12345_?.fits [-s] [-d 5.0] [-f 1]
                                 [-m 50000] [-r 2.0] [-rm 5.0] [-in]

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Note that the recipe can be used on a single coadded image by giving it as input.

Below is an example of an output plot

Figure: Example output plot of PSF_Anistropy