What’s New in Photutils 1.6?

Here we highlight some of the new functionality of the 1.6 release. In addition to these major changes, Photutils 1.6 includes a large number of smaller improvements and bug fixes, which are described in the full Changelog.

New centroids available in SourceCatalog

New centroids were added to the SourceCatalog class, including iteratively-calculated “windowed” centroids and centroids calculated by fitting a 2D quadratic polynomial to the unmasked pixels in the source segment.

The “windowed” centroids are equivalent the SourceExtractors XWIN_IMAGE and YWIN_IMAGE parameters. The new “windowed” centroid properties are:

The “quadratic” centroids are calculated using centroid_quadratic. The new quadratic centroid properties are:

Slicing a SegmentationImage

SegmentationImage objects can now be sliced in x and y, generating a new SegmentationImage object.

New ImageDepth class

A new ImageDepth class was added to compute the limiting fluxes and magnitudes of an image.


The ApertureStats class now accepts NDData objects as input.

Progress Bars in SourceCatalog and PSF fitting

An progress_bar keyword option was added to SourceCatalog to enable progress bars when calculating some properties (e.g., kron_radius, kron_flux, fluxfrac_radius, circular_photometry, centroid_win, centroid_quad).

An option to enable progress bars during PSF fitting was added. To enable it, set progress_bar=True when calling the PSF-fitting object on your data. The progress bar tracks progress over the star groups.

The progress bars require installation of the tqdm optional dependency.

New subshape keyword in PSF fitting

A new subshape keyword was added to the PSF-fitting classes to define the shape over which the PSF is subtracted when computing the residual image. Previously, the PSF-subtraction region was always defined by the fitshape keyword. By default (and for backwards compatibility), subshape is set to None, which means the fitshape value will be used.

Other changes

Please see the Changelog for the complete list of changes.