get_dispersion_direction

jwst.lib.dispaxis.get_dispersion_direction(exposure_type, grating='ANY', filter_wh='ANY', pupil='ANY')[source]

Get the dispersion direction.

Parameters:
exposure_typestr

The exposure type.

gratingstr

The name of the optic in the grating wheel.

filter_whstr

The name of the optic in the filter wheel.

pupilstr

The name of the optic in the pupil wheel.

Returns:
selectint or None

The dispersion direction:

  • None: The dispersion direction is not meaningful or not defined.

  • 1: The dispersion direction is horizontal (“sky” coordinates).

  • 2: The dispersion direction is vertical (“sky” coordinates).