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# Download an example FITS file, create a 2D cutout, and save it to a
# new FITS file, including the updated cutout WCS.
from astropy.io import fits
from astropy.nddata import Cutout2D
from astropy.utils.data import download_file
from astropy.wcs import WCS
def download_image_save_cutout(url, position, size):
# Download the image
filename = download_file(url)
# Load the image and the WCS
hdu = fits.open(filename)[0]
wcs = WCS(hdu.header)
# Make the cutout, including the WCS
cutout = Cutout2D(hdu.data, position=position, size=size, wcs=wcs)
# Put the cutout image in the FITS HDU
hdu.data = cutout.data
# Update the FITS header with the cutout WCS
hdu.header.update(cutout.wcs.to_header())
# Write the cutout to a new FITS file
cutout_filename = "example_cutout.fits"
hdu.writeto(cutout_filename, overwrite=True)
if __name__ == "__main__":
url = "https://astropy.stsci.edu/data/photometry/spitzer_example_image.fits"
position = (500, 300)
size = (400, 400)
download_image_save_cutout(url, position, size)
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