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Automatic Guide Star Selection Parameters

The automatic guide star parameters used by the 2013A PIT for conditions CC50, IQ70, and SB50 are given in Table 1. These are modified for the conditions by the values in Table 2. The UCAC3 catalog is queried using the parameters given for the instrument/mode given in the observation. The UCAC3 magnituide f.mag is compared with the R-magnitude limits from the tables. For the GMOS and FLAMINGOS-2 OIWFS wavefront sensors (WFS) and GeMS Canopus WFS a complete range of PAs is checked and the fraction of steps with valid guide stars in the WFS patrol field is returned. The GeMS algorithm searches for 2 or 3 star Canopus (CWFS) asterisms with one ODGW flexure compensation star.

Table 1. Standard guide star query parmaters. 

Instrument Guider Mode Min Radius ['] Max Radius ['] Min mag Max mag Bandpass    
GMOS-N/S PWFS2 Non-sidereal 5.3 6.95 9.0 14.5 R  
NIRI PWFS2 f/6 5.2 6.95 9.0 14.5 R  
NIRI PWFS2 f/14 4.8 6.95 9.0 14.5 R  
NIRI PWFS2 f/32 4.3 6.95 9.0 14.5 R  
NIFS PWFS2   4 6.95 9.0 14.5 R  
GNIRS PWFS2   4.8 6.95 9.0 14.5 R  
Michelle PWFS2 chopping 4.8 6.95 7.5 13.0 R  
T-ReCS PWFS2 chopping 4.8 6.95 7.5 13.0 R  
             
NIRI PWFS1 f/14 5.3 6.95 9.0 14.5 R Used for LGS+PWFS1  
NIRI PWFS1 f/32 4.8 6.95 9.0 14.5 R Used for LGS+PWFS1  
NIFS PWFS1   4.8 6.95 9.0 14.5 R Used for LGS+PWFS1  
GNIRS PWFS1   4.8 6.95 9.0 14.5 R Used for LGS+PWFS1  
             
FLAMINGOS-2 F2 OIWFS   0.33 6.1 9.5 15.0 R OI geometry used, PAs checked
GMOS-N/S GMOS OIWFS Sidereal 0.33 4.8 9.5 15.5 R OI geometry used, PAs checked
NICI NICI OIWFS           Assumes target is always guidestar
Altair AOWFS Natural Guide Star 0 0.45 -2.0 15.0 R AOWFS geometry used
Altair AOWFS Laser Guide Star 0 0.45 -2.0 18.0 R AOWFS geometry used
Canopus
CWFS
Laser Guide Star
0 1.15 8.0 18.0 R Searches for 2 or 3 star asterisms

Table 2. Conditions-dependent corrections to guide star magnitude limits.

 Conditions Delta mag 

Bandpass 

 CC50  0.0  All
 CC70  -0.3  All
 CC80  -1.0  All
 CCAny  -3.0  All
 IQ20  +0.5  R
 IQ70  0.0  R
 IQ85  -0.5  R
 IQAny  -1.0  R
 SB20  0.0  R
 SB50  0.0  R
 SB80  -0.3  R
 SBAny  -0.5  R