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****************************
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
:ref:`changelog`.

.. contents::
   :local:
   :depth: 2


New centroids available in SourceCatalog
========================================

New centroids were added to the
:class:`~photutils.segmentation.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:

* :attr:`~photutils.segmentation.SourceCatalog.centroid_win`
* :attr:`~photutils.segmentation.SourceCatalog.cutout_centroid_win`
* :attr:`~photutils.segmentation.SourceCatalog.xcentroid_win`
* :attr:`~photutils.segmentation.SourceCatalog.ycentroid_win`
* :attr:`~photutils.segmentation.SourceCatalog.sky_centroid_win`

The "quadratic" centroids are calculated using
`~photutils.centroids.centroid_quadratic`. The new quadratic centroid
properties are:

* :attr:`~photutils.segmentation.SourceCatalog.centroid_quad`
* :attr:`~photutils.segmentation.SourceCatalog.cutout_centroid_quad`
* :attr:`~photutils.segmentation.SourceCatalog.xcentroid_quad`
* :attr:`~photutils.segmentation.SourceCatalog.ycentroid_quad`
* :attr:`~photutils.segmentation.SourceCatalog.sky_centroid_quad`


Slicing a SegmentationImage
===========================

:class:`~photutils.segmentation.SegmentationImage`
objects can now be sliced in x and y, generating a new
:class:`~photutils.segmentation.SegmentationImage` object.


New ImageDepth class
====================

A new :class:`~photutils.utils.ImageDepth` class was added to compute
the limiting fluxes and magnitudes of an image.


ApertureStats
=============

The :class:`~photutils.aperture.ApertureStats` class now accepts
`~astropy.nddata.NDData` objects as input.


Progress Bars in SourceCatalog and PSF fitting
==============================================

An ``progress_bar`` keyword option was added to
`~photutils.segmentation.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
<https://tqdm.github.io/>`_ 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 :ref:`changelog` for the complete list of changes.
