Finding Guide Stars

The simplest option is to use the configuration defaults. To find stars for the INT, use commands like the following:

$GSS
GSS>CONFIG INT CASS
GSS>ROTATOR 90
GSS>SEARCH 12 34 56.23 30 00 02 J2000
GSS>EXIT
$TYPE OUTPUT.GS

This finds the brightest 10 guide stars available for the INT Cass focus at the specified position for sky position angle $90o$. The position and probe coordinates for the guide star are given in OUTPUT.GS, which is the default output file name.

The next example shows how to increase the number of potential guide stars and to produce a plot of the results for the INT Prime focus.

$XDISPLAY
$GSS
GSS>CONFIG INT PRIME
GSS>ROTATOR 180
GSS>NUMBER 50
GSS>DEVICE XWINDOWS
GSS>SEARCH 23 23 24.56 45 56 23.1 B1950
GSS>PLOT
GSS>EXIT
$TYPE OUTPUT.GS

produces an X-windows plot.

On La Palma, the guide star details may be printed using WHT_LASE OUTPUT. GS or INT_LASE OUTPUT.GS. To get a hard copy of the plot, use CANON_L as the device name, and use WHT_GLASE or INT_GLASE to print the resulting CANON.DAT file, or POSTSCRIPT_L, followed by WHT_PLASE GKS_72.PS. A complete list of the currently-supported configurations is given in the next section.