Second Example#
Another way of creating a WCS object is via the use of a Python
dictionary. This affords us more control over the NAXISn
FITS header keyword which is otherwise automatically default to zero
as in the case of the First Example shown above.
# Define the astropy.wcs.WCS object using a Python dictionary as input
import astropy.wcs
wcs_dict = {
"CTYPE1": "WAVE ",
"CUNIT1": "Angstrom",
"CDELT1": 0.2,
"CRPIX1": 0,
"CRVAL1": 10,
"NAXIS1": 5,
"CTYPE2": "HPLT-TAN",
"CUNIT2": "deg",
"CDELT2": 0.5,
"CRPIX2": 2,
"CRVAL2": 0.5,
"NAXIS2": 4,
"CTYPE3": "HPLN-TAN",
"CUNIT3": "deg",
"CDELT3": 0.4,
"CRPIX3": 2,
"CRVAL3": 1,
"NAXIS3": 3,
}
input_wcs = astropy.wcs.WCS(wcs_dict)