What’s New in Photutils 1.11?

Here we highlight some of the new functionality of the 1.11 release. In addition to these changes, Photutils 1.11 includes a large number of smaller improvements and bug fixes, which are described in the full Changelog.

SourceFinder npixels tuple input

The SourceFinder npixels keyword can now be a tuple corresponding to the values used for the source finder and source deblender, respectively.

GriddedPSFModel Memory Usage

The memory usage during PSF photometry when using a GriddedPSFModel PSF model has been significantly reduced. This is especially noticeable when fitting a large number of stars.

New IterativePSFPhotometry mode keyword

A mode keyword was added to IterativePSFPhotometry for controlling the fitting mode. The mode keyword can be set to ‘new’ or ‘all’.

For the ‘new’ mode (default), PSF photometry is run in each iteration only on the new sources detected in the residual image. The ‘new’ mode preserves the previous behavior of IterativePSFPhotometry.

For the ‘all’ mode, PSF photometry is run in each iteration on all the detected sources (from all previous iterations) on the original, unsubtracted, data. For the ‘all’ mode, a source grouper must be input.

Initial tests indicate that the ‘all’ mode may give better results than the older ‘new’ method.

New include_localbkg keyword

The PSF photometry make_model_image and make_residual_image methods no longer include the local background by default, which causes issues if the psf_shape of sources overlap. This is a backwards-incompatible change. These methods now accept an include_localbkg keyword . If the previous behavior is desired, set include_localbkg=True.