A specialized version of usno_look designed to establish a CDFP file of standards to be used in deriving a WCS or photometric solution. Many of the methods used in this routine are discussed in a document about building finding charts with the USNO and DSS resources. A useful wrapper for this routine is usno_look_wcs_run.

% usno_look_wcs --help    
Usage: usno_look_wcs 20170903T034319.0_acm_sci.fits magB1 18.00 1  
arg1 - name of FITS image with WCS installed 
arg2 - mag name to be used for limit (magB1,magB2,magB2,magR2,V) 
arg3 - magnitude limit 
arg4 - ds9 frame to display in  (0 for no disply) 

# In this example, the result would a file named:  20170903T034319.0_acm_sci.cdfp  

Following the end of a normal usno_look_wcs run there should be three new files. Assuming the basename of the input image was "20190217T022612.7_acm_sci", then the three files would be:

20190217T022612.7_acm_sci-usno.cdfp 
   The cdfp file file of USNO-B1.0 targets after the problem sources 
   have been graphically deleted.  
   
20190217T022612.7_acm_sci-usno.png 
   A png image file of the field with the final sources marked in blue. 

usno_targs.cdfp 
  A copy of the above cdfp file. This is left in place because some 
  downstream scripts will recognize and use only the name "usno_targs.cdfp". 

The original image and overplotted USNO sources obtained when I ran: % usno_look_wcs 20190217T022612.7_acm_sci.fits Blue 18.0 1 arg1 - name of FITS image with WCS installed arg2 - mag name to be used for limit (query,Blue,V,Red) arg3 - magnitude limit arg4 - ds9 frame to display in (0 for no disply) Some of these targets may be too close to the image edge or may be too faint for use in WCS calibration.

The editted version of the USNO sources that are written to the final cdfp file. I have removed a few targets that may cause errors in the WCS calibration routine (for example). The final cdfp file is named 20190217T022612.7_acm_sci.cdfp. Notice that the numbers attached tro the targets have changed. This is because the image "names" in a cdfp file are always just the line number (after header) of the source in the cdfp file.

Some notes (useful to SCO) that summarize routines used in this code:

 ds9_get_circle_text 
   Extract the text names of the circles regions in a ds9 regions file. 


cdfp_filter_by_linenum.sh 
   OTW code to that reads a set of region names (i.e. line numbers in a 
   cdfp file) and filter an input cdfp file so that the resulting catalog 
   contains only the sources listed in the name file.  

This routine has also been testsed for use with PFC images. Here the number of star can be quite large given the 40 arcminute size of the PFC field. Here are some typical examples:

usno_look_wcs Rsco3228.fits Blue 18.00 1 
usno_look_wcs Rsco3228.fits V 18 1 
usno_look_wcs Rsco3228.fits Red 18 1 
># A more reasonable number of stars is obtained by lowering the magnitude limits 
usno_look_wcs Rsco3228.fits Red 14.0 1 
 

A convenient wrapper script: This routine has proven to be very useful, but one thing became apparent about its efficient use: I need a way to rapidly change the limiting magnitude. Rather than dink endlessly with usno_look_wcs I decided to write a simple wrapper script:

 Usage: usno_look_wcs_run ./local_red/WCS/Rsco2039.fits N  
arg1 - Name of FITS image (can be full path)
arg2 - run in debug mode (Y/N)

July2018 Improvement: We can use this routine to gather ds9 objects for mido.sh photometry, but we really need a way to specify the aperture size interactively. As covered in the "--help" message for usno_look_wcs, I now allow the user to use the magname value of "query". This activates (withing usno_look_wcs) a mode where the user specifies the cricle radius (in pixels) and the color of the circle mar Here is an example of a call using this mode:

 Usage: usno_look_wcs Rsco2039.fits query 18 1