dva_corr_model

romanisim.wcs.dva_corr_model(va_scale, v2_ref, v3_ref)

Create transformation that accounts for differential velocity aberration (scale).

Parameters:

va_scalefloat, None

Ratio of the apparent plate scale to the true plate scale. When va_scale is None, it is assumed to be identical to 1 and an astropy.modeling.models.Identity model will be returned.

v2_reffloat, None

Telescope v2 coordinate of the reference point in arcsec. When v2_ref is None, it is assumed to be identical to 0.

v3_reffloat, None

Telescope v3 coordinate of the reference point in arcsec. When v3_ref is None, it is assumed to be identical to 0.

Returns:

va_corrastropy.modeling.CompoundModel, astropy.modeling.models.Identity

A 2D compound model that corrects DVA. If va_scale is None or 1 then astropy.modeling.models.Identity will be returned.