Actions

SOURCE

sourcename, where sourcename is an object in the current catalogue causes the GSC to be searched around its position using the current configuration and rotator PA. The name should follow the requirements of the WHT TCS (up to 20 characters; embedded spaces require double quotes).

SEARCH

RA Dec Equinox Proper motions Epoch Parallax Radial Velocity. Search the catalogue for guide stars around the given target position. The first three parameters are required. The remainder are optional qualifiers, as follows:

/RAPROPER

proper motion in RA (seconds of time per year)

/DECPROPER

proper motion in Dec (arcseconds per year).

/EPOCH

(year). Defaults to equinox.

/PARALLAX

(arcsec). Defaults to zero.

/RADVEL

radial velocity (kms ; defaults to zero).

Examples:

SEARCH 20 12 13.33 -30 45 55.2 B1950
SEARCH 19 57 57 30.233 04 06.77 J2000 /RAP=0.001 /DECP=-0.12 /EP=1945.5

This command is for use when a catalogue has not been specified (e.g. for small numbers of objects).

PLOT

Plot the positions of the selected guide stars. The plot is centred on the target position (marked by a star) and shows the positions of the selected guide stars in the focal plane coordinate system (x left-right; y up-down; PA vertical). The outline of the field is drawn, together with an ``L'' indicating North and East. An open circle indicates that the object is classified as stellar on all available plates. A circle with a superposed x represents an ambiguous classification and one with a superposed + has a non-stellar classfication on all plates. Larger circles correspond to brighter objects.

DO

Filename. Search the GSC using commands from the specified file rather than interactive input. Default to .COM extension.

OUTPUT

Filename. Specifies that a new output file be created and used until further notice. Standard VMS syntax, defaulting to OUTPUT.GS in the current directory.

SHOW

List the current configuration data.

HELP

Access to help text (not yet enabled).

EXIT

Stop the program and dismount the disks.