read_offset_wcs

lsst.images.fits.read_offset_wcs(header: Header, *, key: str = 'A') → tuple[int, int] | None

Recover the logical pixel origin from a linear offset WCS written by add_offset_wcs.

Parameters

header

Header to read from.

key

Single-character suffix for the WCS to read.

Returns

tuple [int, int] | None

The (x, y) logical coordinates of the first column and row, or None if the header has no LINEAR WCS with this suffix.