Check an output line from hacalc. If the HA does not satisfy a track (or hacalc.out is not present), then return -999.000. If the a track is satified, then return the AZIMUTH of that track.

% hacalc_chek.sh 
Usage: hacalc_chek -1.667  
arg1 - object hour angle (HA in floating point HOURS)

EXAMPLES: 
% cat hacalc.out
2   147.888    -1.750    -0.617   212.112     0.617     1.750

%  hacalc_chek.sh -0.8 
 147.888

%  hacalc_chek.sh +0.85 
 212.112

%  hacalc_chek.sh +2.7883 
-999.000

Some explanation of hacalc

A c code (halcalc) that predicts properties of an HET track based on the input declination is used to generat the file named "hacalc.out" above. It has a variable output that depends on the possible number of tracks (East, West, East and West). If only one track is predicted, it is referred to as an East track. The input to hacalc is the floating point DEC (in degrees) and the output of hacalc is:

% hacalc  41.274166  
2    60.651    -3.530    -2.030   299.349     2.030     3.530
nt     AZe      ha1e      ha2e      AZw        ha1w      ha2w

nt   = number of possible tracks 

AZe  = azimuth of the east track 
ha1e = hour angle at start of east track  
ha2e = hour angle at end of east track  

AZw  = azimuth of the west track 
ha1w = hour angle at start of west track  
ha2w = hour angle at end of west track  

Here is an example of dec that has only one track:
% hacalc 66.0 
1     0.000    -1.383     1.383