The fgstar routine, given a position in Ra,Dec coordinates, provides a view of the IHMP (Input Head Mounting Plate) projeted on the sky. This is a Fast vereion of an old code name gstar (Guide STAR), which was used primarily to locate stars that could be used by the guide probes (gc1,gc2) or wavefornt sensors (wf1,wf2).

For a more detiled description see:
%  fgstar --help 

Usage: fgstar 06:15:20.46 +39:51:50.6 304.0 gc1 N
arg1 - RA of IHMP center (sexigecimal)
arg2 - DEC of IHMP center (sexigecimal)
arg3 - Azimuth of HET structure (degrees)
arg4 - probe name (valid names = gc1,gc2,wf1,wf2) 
arg5 - run in verbose/debug mode (Y/N) 

Below I show a typical example where I use a local file named "Faint_Mag.Limit" to set the magnitude limit for stars plotted in the gc1 pickle to be 16.5 (in the USNO-B1.0 Red2 system). Note that had we not created this file a default value of Red2=18.0 would have been used. Also, by creating the "No.Mark" file, I establish that the routine will exit after the finding chart is created. Otherwise, the user will be told to mark a circle region in the pickle. The (Ra,Dec) of that circle region cenetr will then be written to a local file named "radec.gc1".

% ls 
Faint_Mag.Limit
% cat Faint_Mag.Limit 
16.5
% date > No.Mark  
% fgstar 06:15:20.46 +39:51:50.6 304.0 gc1 N  

The initial view of a finding chart made with fgstar. The important IHMP positions are projected onto the sky for an observation with the HET when the IHMP cnter is located at RA,DEC = 06:15:20.46 +39:51:50.6 (J2000.0). Note that each IFU is labeled with its 3-digit (color-row) indentification string. The purple stars labeled in the gc1 pickle region are stars brighter than Red2=16.5 in the USNO-B1.0 catalog. The bold, red text strings in the upper right corner are the names of each probe stacked upon one another. This once served a purpose, but is now a seldom-used feature that should be ignored.

We have zoomed into the central portion of the first figure shown above. The yellow square is the outline of the acm (ACquisition caMera) and the small yellow circle indicates the corner of the acm with pixel X,Y coordinates 1,1. The thicker yellow line indicates the Y=0 X axis of the acm image. The thick red circle indicates the center of the IHMP. This position is also sometimes referrred to as the "boresite". The LRS-R (066) and LRS2-B (056) IFU outlines are drawn in. The position of of the BIB camera is shown by the string "BIB". The actual field of the BIB is much smaller than this label, but the BIB position is centered on the "I" character in this text string. Note that fgstar pre-dated the HPF and hence no HPF markeres are indicated.