Coordinate Systems

The RTD understands and supports the following coordinate systems:

Coordinate System	Description
canvas	canvas coordinates (canvas scroll area)
screen	canvas window coords (visible area)
image	basic image pixel coords (at mag 1, no transformations)
chip	detector chip coordinates (based on ESO extended FITS keywords: DET CHIP...)
wcs equinox	world coordinates in H:M:S
deg equinox	world coordinates in degrees

Where it makes sense to do so, the RTD subcommands accept coordinates of the form:

 
$x $y $coord_type

Where $x and $y are the coordinate values and the coordinate type is one of the types in the above table. For world coordinates, the equinox may also be included as part of the coordinate type specification, for example:

 
$image get $ra $dec "wcs 1950"