Compute the HET parallactic angle, Q. This is actually the direction of the parallactic angle vector for a target at the center of the HET track. The tcs optaz() routine is used to estimate the the structure Azimuth for the input declination, and then hetparang computes Q. A coolection of notes on parallactic angle calculations cane be viewed here.

 
 

%  hetparangle.sh 32.500 E 
    98.30782

%  hetparangle.sh --help  

Help Information for:  hetparangle.sh

Usage: hetparangle.sh 32.500 E
arg1 - Declination (float) degrees
arg2 - E,W  (East or West)

I will show: /home/sco/sco/codes/bash/HELP_FILES/hetparangle.sh.help

Enter any key to roceed with the view of help:
hetparangle.sh:
   A routine to compute the HET parallactic angle based on the declination 
   and direction (E or W of the meridian). The parallactic angle is always 
   based on the azimuth being used, which is usally a direct function of the 
   target declination. I used to use the old hacalc routine to compute AZ based 
   on the input DEC. However, in Jan2017 I switched to using the newer hetaz.py 
   routine to be compatable compatible with Niv Drory's optaz() tcs function. 
  
A call to hetaz.py looks like: 
% hetaz.py 32.5000
  76.017  283.983 
where values for East (1) and West (2) azimuths are always output. 

Note that this routine assumes the OPTIMAL HET AZIMUTH. If a non-standard azimuth 
was used, then the results with hetparangle.sh will be INCORRECT. 

 
 
hetaz.py is in:   mopy,   codes/python/coords/hetaz.py