How to cut out Target Pixel Files from Kepler Superstamps or TESS FFIs?¶

You can use lightkurve to cut Target Pixel Files (TPFs) out of a series of standard astronomical images, such as K2 Superstamp Mosaics or TESS Full-Frame-Images (FFIs). This brief tutorial will demonstrate how!

Let’s assume you have downloaded a set simulated TESS FFI images to a local directory called data. lightkurve will assume that the files are given in time order. So we’ll sort the filenames first:

[1]:

from glob import glob
import numpy as np

Now we use the KeplerTargetPixelFile class and its function from_fits_images() to create the new TPF. This will cut out around the position keyword. You can pass a pixel position in units of the original image or RA and Dec coordinates.

[ ]:

from lightkurve import KeplerTargetPixelFile
from astropy.coordinates import SkyCoord

fnames = np.sort(glob('data/*.fits'))
tpf = KeplerTargetPixelFile.from_fits_images(images=fnames,
                                             position=SkyCoord(257.13700, 24.48958, unit='deg'),
                                             size=(9,9),
                                             target_id='MyCutOut')

We then have a fully functioning KeplerTargetPixelFile object! You can read more about such objects in the tutorial on their use.

[ ]:

%matplotlib inline
#tpf.plot();