========================
New Features
------------
astropy.convolution
^^^^^^^^^^^^^^^^^^^
- Change padding sizes for ``fft_pad`` in ``convolve_fft`` from powers of
2 only to scipy-optimized numbers, applied separately to each dimension;
yielding some performance gains and avoiding potential large memory
impact for certain multi-dimensional inputs. [11533]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- Adds the ability to create topocentric ``CIRS`` frames. Using these,
``AltAz`` calculations are now accurate down to the milli-arcsecond
level. [10994]
- Adds a direct transformation from ``ICRS`` to ``AltAz`` frames. This
provides a modest speedup of approximately 10 percent. [11079]
- Adds new ``WGS84GeodeticRepresentation``, ``WGS72GeodeticRepresentation``,
and ``GRS80GeodeticRepresentation``. These are mostly for use inside
``EarthLocation`` but can also be used to convert between geocentric
(cartesian) and different geodetic representations directly. [11086]
- ``SkyCoord.guess_from_table`` now also searches for differentials in the table.
In addition, multiple regex matches can be resolved when they are exact
component names, e.g. having both columns “dec” and “pm_dec” no longer errors
and will be included in the SkyCoord. [11417]
- All representations now have a ``transform`` method, which allows them to be
transformed by a 3x3 matrix in a Cartesian basis. By default, transformations
are routed through ``CartesianRepresentation``. ``SphericalRepresentation`` and
``PhysicssphericalRepresentation`` override this for speed and to prevent NaN
leakage from the distance to the angular components.
Also, the functions ``is_O3`` and ``is_rotation`` have been added to
``matrix_utities`` for checking whether a matrix is in the O(3) group or is a
rotation (proper or improper), respectively. [11444]
- Moved angle formatting and parsing utilities to
``astropy.coordinates.angle_formats``.
Added new functionality to ``astropy.coordinates.angle_utilities`` for
generating points on or in spherical surfaces, either randomly or on a grid. [11628]
- Added a new method to ``SkyCoord``, ``spherical_offsets_by()``, which is the
conceptual inverse of ``spherical_offsets_to()``: Given angular offsets in
longitude and latitude, this method returns a new coordinate with the offsets
applied. [11635]
- Refactor conversions between ``GCRS`` and ``CIRS,TETE`` for better accuracy
and substantially improved speed. [11069]
- Also refactor ``EarthLocation.get_gcrs`` for an increase in performance of
an order of magnitude, which enters as well in getting observed positions of
planets using ``get_body``. [11073]
- Refactored the usage of metaclasses in ``astropy.coordinates`` to instead use
``__init_subclass__`` where possible. [11090]
- Removed duplicate calls to transform_to from match_to_catalog_sky
and match_to_catalog_3d, improving their performance. [11449]
- The new DE440 and DE440s ephemerides are now available via shortcuts 'de440'
and 'de440s'. The DE 440s ephemeris will probably become the default
ephemeris when choosing 'jpl' in 5.0. [11601]
astropy.cosmology
^^^^^^^^^^^^^^^^^
- Cosmology parameter dictionaries now also specify the Cosmology class to which
the parameters correspond. For example, the dictionary for
``astropy.cosmology.parameters.Planck18`` has the added key-value pair
("cosmology", "FlatLambdaCDM"). [11530]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Added support for reading and writing ASCII tables in QDP (Quick and Dandy
Plotter) format. [11256]
- Added support for reading and writing multidimensional column data (masked and
unmasked) to ECSV. Also added formal support for reading and writing object-type
column data which can contain items consisting of lists, dicts, and basic scalar
types. This can be used to store columns of variable-length arrays. Both of
these features use JSON to convert the object to a string that is stored in the
ECSV output. [11569, 11662, 11720]
astropy.io.fits
^^^^^^^^^^^^^^^
- Added ``append`` keyword to append table objects to an existing FITS file [2632, 11149]
- Check that the SIMPLE card is present when opening a file, to ensure that the
file is a valid FITS file and raise a better error when opening a non FITS
one. ``ignore_missing_simple`` can be used to skip this verification. [10895]
- Expose ``Header.strip`` as a public method, to remove the most common
structural keywords. [11174]
- Enable the use of ``os.PathLike`` objects when dealing with (mainly FITS) files. [11580]
astropy.io.registry
^^^^^^^^^^^^^^^^^^^
- Readers and writers can now set a priority, to assist with resolving which
format to use. [11214]
astropy.io.votable
^^^^^^^^^^^^^^^^^^
- Version 1.4 VOTables now use the VOUnit format specification. [11032]
- When reading VOTables using the Unified File Read/Write Interface (i.e. using
the ``Table.read()`` or ``QTable.read()`` functions) it is now possible to
specify all keyword arguments that are valid for
``astropy.io.votable.table.parse()``. [11643]
astropy.modeling
^^^^^^^^^^^^^^^^
- Added a state attribute to models to allow preventing the syncing of
constraint values from the constituent models. This syncing can
greatly slow down fitting if there are large numbers of fit parameters.
model.sync_constraints = True means check constituent model constraints
for compound models every time the constraint is accessed, False, do not.
Fitters that support constraints will set this to False on the model copy
and then set back to True when the fit is complete before returning. [11365]
- The ``convolve_models_fft`` function implements model convolution so that one
insures that the convolution remains consistent across multiple different
inputs. [11456]
astropy.nddata
^^^^^^^^^^^^^^
- Prevent unnecessary copies of the data during ``NDData`` arithmetic when units
need to be added. [11107]
- NDData str representations now show units, if present. [11553]
astropy.stats
^^^^^^^^^^^^^
- Added the ability to specify stdfunc='mad_std' when doing sigma clipping,
which will use a built-in function and lead to significant performance
improvements if cenfunc is 'mean' or 'median'. [11664]
- Significantly improved the performance of sigma clipping when cenfunc and
stdfunc are passed as strings and the ``grow`` option is not used. [11219]
- Improved performance of ``bayesian_blocks()`` by removing one ``np.log()``
call [11356]
astropy.table
^^^^^^^^^^^^^
- Add table attributes to include or exclude columns from the output when
printing a table. This functionality includes a context manager to
include/exclude columns temporarily. [11190]
- Improved the string representation of objects related to ``Table.indices`` so
they now indicate the object type and relevant attributes. [11333]
astropy.timeseries
^^^^^^^^^^^^^^^^^^
- An exception is raised when ``n_bins`` is passed as an argument while
any of the parameters ``time_bin_start`` or ``time_bin_size`` is not
scalar. [11463]
astropy.units
^^^^^^^^^^^^^
- The ``physical_type`` attributes of each unit are now objects of the (new)
``astropy.units.physical.PhysicalType`` class instead of strings and the
function ``astropy.units.physical.get_physical_type`` can now translate
strings to these objects. [11204]
- The function ``astropy.units.physical.def_physical_type`` was created to
either define entirely new physical types, or to add more physical type
names to an existing physical types. [11204]
- ``PhysicalType``'s can be operated on using operations multiplication,
division, and exponentiation are to facilitate dimensional analysis. [11204]
- It is now possible to define aliases for units using
``astropy.units.set_enabled_aliases``. This can be used when reading files
that have misspelled units. [11258]
- Add a new "DN" unit, ``units.dn`` or ``units.DN``, representing data number
for a detector. [11591]
astropy.utils
^^^^^^^^^^^^^
- Added ``ssl_context`` and ``allow_insecure`` options to ``download_file``,
as well as the ability to optionally use the ``certifi`` package to provide
root CA certificates when downloading from sites secured with
TLS/SSL. [10434]
- ``astropy.utils.data.get_pkg_data_path`` is publicly scoped (previously the
private function ``_find_pkg_data_path``) for obtaining file paths without
checking if the file/directory exists, as long as the package and module
do. [11006]
- Deprecated ``astropy.utils.OrderedDescriptor`` and
``astropy.utils.OrderedDescriptorContainer``, as new features in Python 3
make their use less compelling. [11094, 11099]
- ``astropy.utils.masked`` provides a new ``Masked`` class/factory that can be
used to represent masked ``ndarray`` and all its subclasses, including
``Quantity`` and its subclasses. These classes can be used inside
coordinates, but the mask is not yet exposed. Generally, the interface should
be considered experimental. [11127, 11792]
- Add new ``utils.parsing`` module to with helper wrappers around
``ply``. [11227]
- Change the Time and IERS leap second handling so that the leap second table is
updated only when a Time transform involving UTC is performed. Previously this
update check was done the first time a ``Time`` object was created, which in
practice occurred when importing common astropy subpackages like
``astropy.coordinates``. Now you can prevent querying internet resources (for
instance on a cluster) by setting ``iers.conf.auto_download = False``. This
can be done after importing astropy but prior to performing any ``Time``
scale transformations related to UTC. [11638]
- Added a new module at ``astropy.utils.compat.optional_deps`` to consolidate
the definition of ``HAS_x`` optional dependency flag variables,
like ``HAS_SCIPY``. [11490]
astropy.wcs
^^^^^^^^^^^
- Add IVOA UCD mappings for some FITS WCS keywords commonly used in solar
physics. [10965]
- Add ``STOKES`` FITS WCS keyword to the IVOA UCD mapping. [11236]
- Updated bundled version of WCSLIB to version 7.6. See
https://www.atnf.csiro.au/people/mcalabre/WCS/CHANGES for a list of
included changes. [11549]
API Changes
-----------
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- For input to representations, subclasses of the class required for a
given attribute will now be allowed in. [11113]
- Except for ``UnitSphericalRepresentation``, shortcuts in representations now
allow for attached differentials. [11467]
- Allow coordinate name strings as input to
``SkyCoord.is_transformable_to``. [11552]
astropy.cosmology
^^^^^^^^^^^^^^^^^
- Change ``z_at_value`` to use ``scipy.optimize.minimize_scalar`` with default
method ``Brent`` (other options ``Bounded`` and ``Golden``) and accept
``bracket`` option to set initial search region. [11080]
- Clarified definition of inputs to ``angular_diameter_distance_z1z2``.
The function now emits ``AstropyUserWarning`` when ``z2`` is less than
``z1``. [11197]
- Split cosmology realizations from core classes, moving the former to new file
``realizations``. [11345]
- Since cosmologies are immutable, the initialization signature and values can
be stored, greatly simplifying cloning logic and extending it to user-defined
cosmology classes that do not have attributes with the same name as each
initialization argument. [11515]
- Cloning a cosmology with changed parameter(s) now appends "(modified)" to the
new instance's name, unless a name is explicitly passed to ``clone``. [11536]
- Allow ``m_nu`` to be input as any quantity-like or array-like -- Quantity,
array, float, str, etc. Input is passed to the Quantity constructor and
converted to eV, still with the prior mass-energy equivalence
enabled. [11640]
astropy.io.fits
^^^^^^^^^^^^^^^
- For conversion between FITS tables and astropy ``Table``, the standard mask
values of ``NaN`` for float and null string for string are now properly
recognized, leading to a ``MaskedColumn`` with appropriately set mask
instead of a ``Column`` with those values exposed. Conversely, when writing
an astropy ``Table`` to a FITS tables, masked values are now consistently
converted to the standard FITS mask values of ``NaN`` for float and null
string for string (i.e., not just for tables with ``masked=True``, which no
longer is guaranteed to signal the presence of ``MaskedColumn``). [11222]
astropy.io.votable
^^^^^^^^^^^^^^^^^^
- The use of ``version='1.0'`` is now fully deprecated in constructing
a ``astropy.io.votable.tree.VOTableFile``. [11659]
astropy.modeling
^^^^^^^^^^^^^^^^
- Removed deprecated ``astropy.modeling.blackbody`` module. [10972]
astropy.table
^^^^^^^^^^^^^
- Added ``Column.value`` as an alias for the existing ``Column.data`` attribute.
This makes accessing a column's underlying data array consistent with the
``.value`` attribute available for ``Time`` and ``Quantity`` objects. [10962]
- In reading from a FITS tables, the standard mask values of ``NaN`` for float
and null string for string are properly recognized, leading to a
``MaskedColumn`` with appropriately set mask. [11222]
- Changed the implementation of the ``table.index.Index`` class so instantiating
from this class now returns an ``Index`` object as expected instead of a
``SlicedIndex`` object. [11333]
astropy.units
^^^^^^^^^^^^^
- The ``physical_type`` attribute of units now returns an instance of
``astropy.units.physical.PhysicalType`` instead of a string. Because
``PhysicalType`` instances can be compared to strings, no code changes
should be necessary when making comparisons. The string representations
of different physical types will differ from previous releases. [11204]
- Calling ``Unit()`` with no argument now returns a dimensionless unit,
as was documented but not implemented. [11295]
astropy.utils
^^^^^^^^^^^^^
- Removed deprecated ``utils.misc.InheritDocstrings`` and ``utils.timer``. [10281]
- Removed usage of deprecated ``ipython`` stream in ``utils.console``. [10942]
astropy.wcs
^^^^^^^^^^^
- Deprecate ``accuracy`` argument in ``all_world2pix`` which was mistakenly
*documented*, in the case ``accuracy`` was ever used. [11055]
Bug Fixes
---------
astropy.convolution
^^^^^^^^^^^^^^^^^^^
- Fixes for ``convolve_fft`` documentation examples. [11510]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- Allow ``Distance`` instances with negative distance values as input for
``SphericalRepresentation``. This was always noted as allowed in an
exception message when a negative ``Quantity`` with length units was
passed in, but was not actually possible to do. [11113]
- Makes the ``Angle.to_string`` method to follow the format described in the
docstring with up to 8 significant decimals instead of 4. [11153]
- Ensure that proper motions can be calculated when converting a ``SkyCoord``
with cartesian representation to unit-spherical, by fixing the conversion of
``CartesianDifferential`` to ``UnitSphericalDifferential``. [11469]
- When re-representing coordinates from spherical to unit-spherical and vice
versa, the type of differential will now be preserved. For instance, if only a
radial velocity was present, that will remain the case (previously, a zero
proper motion component was added). [11482]
- Ensure that wrapping of ``Angle`` does not raise a warning even if ``nan`` are
present. Also try to make sure that the result is within the wrapped range
even in the presence of rounding errors. [11568]
- Comparing a non-SkyCoord object to a ``SkyCoord`` using ``==`` no longer
raises an error. [11666]
- Different ``SkyOffsetFrame`` classes no longer interfere with each other,
causing difficult to debug problems with the ``origin`` attribute. The
``origin`` attribute now no longer is propagated, so while it remains
available on a ``SkyCoord`` that is an offset, it no longer is available once
that coordinate is transformed to another frame. [11730] [11730]
astropy.cosmology
^^^^^^^^^^^^^^^^^
- Cosmology instance names are now immutable. [11535]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Fixed bug where writing a table that has comments defined (via
``tbl.meta['comments']``) with the 'csv' format was failing. Since the
formally defined CSV format does not support comments, the comments are now
just ignored unless ``comment=<comment prefix>`` is supplied to the
``write()`` call. [11475]
- Fixed the issue where the CDS reader failed to treat columns
as nullable if the ReadMe file contains a limits specifier. [11531]
- Made sure that the CDS reader does not ignore an order specifier that
may be present after the null specifier '?'. Also made sure that it
checks null values only when an '=' symbol is present and reads
description text even if there is no whitespace after '?'. [11593]
astropy.io.fits
^^^^^^^^^^^^^^^
- Fix ``ColDefs.add_col/del_col`` to allow in-place addition or removal of
a column. [11338]
- Fix indexing of ``fits.Header`` with Numpy integers. [11387]
- Do not delete ``EXTNAME`` for compressed image header if a default and
non-default ``EXTNAME`` are present. [11396]
- Prevent warnings about ``HIERARCH`` with ``CompImageHeader`` class. [11404]
- Fixed regression introduced in Astropy 4.0.5 and 4.2.1 with verification of
FITS headers with HISTORY or COMMENT cards with long (> 72 characters)
values. [11487]
- Fix reading variable-length arrays when there is a gap between the data and the
heap. [11688]
astropy.io.votable
^^^^^^^^^^^^^^^^^^
- ``NumericArray`` converter now properly broadcasts scalar mask to array. [11157]
- VOTables are now written with the correct namespace and schema location
attributes. [11659]
astropy.modeling
^^^^^^^^^^^^^^^^
- Fixes the improper propagation of ``bounding_box`` from
``astropy.modeling.models`` to their inverses. For cases in which the inverses
``bounding_box`` can be determined, the proper calculation has been
implemented. [11414]
- Bugfix to allow rotation models to accept arbitrarily-shaped inputs. [11435]
- Bugfixes for ``astropy.modeling`` to allow ``fix_inputs`` to accept empty
dictionaries and dictionaries with ``numpy`` integer keys. [11443]
- Bugfix for how ``SPECIAL_OPERATORS`` are handled. [11512]
- Fixes ``Model`` crashes when some inputs are scalars and during some types of
output reshaping. [11548]
- Fixed bug in ``LevMarLSQFitter`` when using weights and vector inputs. [11603]
astropy.stats
^^^^^^^^^^^^^
- Fixed a bug with the ``copy=False`` option when carrying out sigma
clipping - previously if ``masked=False`` this still copied the data,
but this will now change the array in-place. [11219]
astropy.table
^^^^^^^^^^^^^
- Ensure that adding a ``Quantity`` or other mixin column to a ``Table``
does not have side effects, such as creating an associated ``info``
instance (which would lead to slow-down of, e.g., slicing afterwards). [11077]
- When writing to a FITS tables, masked values are again always converted to
the standard FITS mask values of ``NaN`` for float and null string
for string, not just for table with ``masked=True``. [11222]
- Using ``Table.to_pandas()`` on an indexed ``Table`` with masked integer values
now correctly construct the ``pandas.DataFrame``. [11432]
- Fixed ``Table`` HTML representation in Jupyter notebooks so that it is
horizontally scrollable within Visual Studio Code. This was done by wrapping
the ``<table>`` in a ``<div>`` element. [11476]
- Fix a bug where a string-valued ``Column`` that happened to have a ``unit``
attribute could not be added to a ``QTable``. Such columns are now simply
kept as ``Column`` instances (with a warning). [11585]
- Fix an issue in ``Table.to_pandas(index=<colname>)`` where the index column name
was not being set properly for the ``DataFrame`` index. This was introduced by
an API change in pandas version 1.3.0. Previously when creating a ``DataFrame``
with the index set to an astropy ``Column``, the ``DataFrame`` index name was
automatically set to the column name. [11921]
astropy.time
^^^^^^^^^^^^
- Fix a thread-safety issue with initialization of the leap-second table
(which is only an issue when ERFA's built-in table is out of date). [11234]
- Fixed converting a zero-length time object from UTC to
UT1 when an empty array is passed. [11516]
astropy.uncertainty
^^^^^^^^^^^^^^^^^^^
- ``Distribution`` instances can now be used as input to ``Quantity`` to
initialize ``QuantityDistribution``. Hence, ``distribution * unit``
and ``distribution << unit`` will work too. [11210]
astropy.units
^^^^^^^^^^^^^
- Move non-astronomy units from astrophys.py to a new misc.py file. [11142]
- The physical type of ``astropy.units.mol / astropy.units.m ** 3`` is now
defined as molar concentration. It was previously incorrectly defined
as molar volume. [11204]
- Make ufunc helper lookup thread-safe. [11226]
- Make ``Unit`` string parsing (as well as ``Angle`` parsing) thread-safe. [11227]
- Decorator ``astropy.units.decorators.quantity_input`` now only evaluates
return type annotations based on ``UnitBase`` or ``FunctionUnitBase`` types.
Other annotations are skipped over and are not attempted to convert to the
correct type. [11506]
astropy.utils
^^^^^^^^^^^^^
- Make ``lazyproperty`` and ``classdecorator`` thread-safe. This should fix a
number of thread safety issues. [11224]
astropy.visualization
^^^^^^^^^^^^^^^^^^^^^
- Fixed a bug that resulted in some parts of grid lines being visible when they
should have been hidden. [11380]
- Fixed a bug that resulted in ``time_support()`` failing for intervals of
a few months if one of the ticks was the month December. [11615]
astropy.wcs
^^^^^^^^^^^
- ``fit_wcs_from_points`` now produces a WCS with integer ``NAXIXn``
values. [10865]
- Updated bundled version of ``WCSLIB`` to v7.4, fixing a bug that caused
the coefficients of the TPD distortion function to not be written to the
header. [11260]
- Fixed a bug in assigning type when converting ``colsel`` to
``numpy.ndarray``. [11431]
- Added ``WCSCOMPARE_*`` constants to the list of WCSLIB constants
available/exposed through the ``astropy.wcs`` module. [11647]
- Fix a bug that caused APE 14 WCS transformations for FITS WCS with ZOPT, BETA,
VELO, VOPT, or VRAD CTYPE to not work correctly. [11781]
Other Changes and Additions
---------------------------
- The configuration file is no longer created by default when importing astropy
and its existence is no longer required. Affiliated packages should update their
``__init__.py`` module to remove the block using ``update_default_config`` and
``ConfigurationDefaultMissingWarning``. [10877]
- Replace ``pkg_resources`` (from setuptools) with ``importlib.metadata`` which
comes from the stdlib, except for Python 3.7 where the backport package is added
as a new dependency. [11091]
- Turn on numpydoc's ``numpydoc_xref_param_type`` to create cross-references
for the parameter types in the Parameters, Other Parameters, Returns and Yields
sections of the docstrings. [11118]
- Docstrings across the package are standardized to enable references.
Also added is an Astropy glossary-of-terms to define standard inputs,
e.g. ``quantity-like`` indicates an input that can be interpreted by
``astropy.units.Quantity``. [11118]
- Binary wheels are now built to the manylinux2010 specification. These wheels
should be supported on all versions of pip shipped with Python 3.7+. [11377]
- The name of the default branch for the astropy git repository has been renamed
to ``main``, and the documentation and tooling has been updated accordingly.
If you have made a local clone you may wish to update it following the
instructions in the repository's README. [11379]
- Sphinx cross-reference link targets are added for every ``PhysicalType``.
Now in the parameter types in the Parameters, Other Parameters, Returns and
Yields sections of the docstring, the physical type of a quantity can be
annotated in square brackets.
E.g. `` distance : `~astropy.units.Quantity` ['length'] `` [11595]
- The minimum supported version of ``ipython`` is now 4.2. [10942]
- The minimum supported version of ``pyerfa`` is now 1.7.3. [11637]