scopesim.effects.obs_strategies module

Effects describing observing strategies.

• ChopNodCombiner: simulate chop-nod cycle

class scopesim.effects.obs_strategies.ChopNodCombiner(**kwargs)

Bases: Effect

Creates and combines 4 images for each of the chop/nod positions.

• AA : original position (dx, dy) = (0, 0)

• AB : chop position (dx, dy) = chop_offsets

• BA : nod position (dx, dy) = nod_offsets

• BB : chop-nod position (dx, dy) = nod_offsets + chop_offsets

Images are combined using:

im_combined = (AA - AB) - (BA - BB)

If no nod_offset is given, it is set to the inverse of chop_offset.

ChopNodCombiner is a detector effect and should be placed last in the

detector yaml (after the noise effects).

apply_to(obj, **kwargs)

TBA.

required_keys = {'chop_offsets', 'pixel_scale'}

scopesim.effects.obs_strategies.chop_nod_image(img, chop_offsets, nod_offsets=None)

Create four copies and combine in chop-nod pattern.