cwitools.coordinates.get_pkpc_per_px

cwitools.coordinates.get_pkpc_per_px(wcs, redshift=0)

Return the physical size of pixels in proper kpc. Assumes 1:1 aspect ratio.

Args:

wcs (astropy.wcs.WCS): A 2D or 3D astropy WCS object. redshift (float): Cosmological redshift of the field/target.

Returns:

float: Proper kiloparsecs per pixel

Examples:

Note that this method assumes the spatial axes are equal in scale and that the WCS is either (deg, deg, wavelength) or (deg, deg).

>>> from astropy.io import fits
>>> from astropy.wcs import WCS
>>> from cwitools.coordinates import get_pkpc_px
>>> z_target = 1.5
>>> data, header = fits.getdata("targetdata.fits", header=True)
>>> wcs = WCS(header)
>>> px_scale_pkpc = pkpc_per_px(wcs, redshift=z_target)