========================
New Features
------------
astropy.config
^^^^^^^^^^^^^^
- Added new tools ``set_temp_config`` and ``set_temp_cache`` which can be
used either as function decorators or context managers to temporarily
use alternative directories in which to read/write the Astropy config
files and download caches respectively. This is especially useful for
testing, though ``set_temp_cache`` may also be used as a way to provide
an alternative (application specific) download cache for large data files,
rather than relying on the default cache location in users' home
directories. [3975]
astropy.constants
^^^^^^^^^^^^^^^^^
- Added the Thomson scattering cross-section. [3839]
astropy.convolution
^^^^^^^^^^^^^^^^^^^
- Added Moffat2DKernel. [3965]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- Added ``get_constellation`` function and ``SkyCoord.get_constellation``
convenience method to determine the constellation that a coordinate
is in. [3758]
- Added ``PrecessedGeocentric`` frame, which is based on GCRS, but precessed
to a specific requested mean equinox. [3758]
- Added ``Supergalactic`` frame to support de Vaucouleurs supergalactic
coordinates. [3892]
- ``SphericalRepresentation`` now has a ``._unit_representation`` class attribute to specify
an equivalent UnitSphericalRepresentation. This allows subclasses of
representations to pair up correctly. [3757]
- Added functionality to support getting the locations of observatories by
name. See ``astropy.coordinates.EarthLocation.of_site``. [4042]
- Added ecliptic coordinates, including ``GeocentricTrueEcliptic``,
``BarycentricTrueEcliptic``, and ``HeliocentricTrueEcliptic``. [3749]
astropy.cosmology
^^^^^^^^^^^^^^^^^
- Add Planck 2015 cosmology [3476]
- Distance calculations now > 20-40x faster for the supplied
cosmologies due to implementing Cython scalar versions of
``FLRW.inv_efunc``.[4127]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Automatically use ``guess=False`` when reading if the file ``format`` is
provided and the format parameters are uniquely specified. This update
also removes duplicate format guesses to improve performance. [3418]
- Calls to ascii.read() for fixed-width tables may now omit one of the keyword
arguments ``col_starts`` or ``col_ends``. Columns will be assumed to begin and
end immediately adjacent to each other. [3657]
- Add a function ``get_read_trace()`` that returns a traceback of the
attempted read formats for the last call to ``astropy.io.ascii.read``. [3688]
- Supports LZMA decompression via ``get_readable_fileobj`` [3667]
- Allow ``-`` character is Sextractor format column names. [4168]
- Improve DAOphot reader to read multi-aperture files [3535, 4207]
astropy.io.fits
^^^^^^^^^^^^^^^
- Support reading and writing from bzip2 compressed files. i.e. ``.fits.bz2``
files. [3789]
- Included a new command-line script called ``fitsinfo`` to display
a summary of the HDUs in one or more FITS files. [3677]
astropy.io.misc
^^^^^^^^^^^^^^^
- Support saving all meta information, description and units of tables and columns
in HDF5 files [4103]
astropy.io.votable
^^^^^^^^^^^^^^^^^^
- A new method was added to ``astropy.io.votable.VOTable``,
``get_info_by_id`` to conveniently find an ``INFO`` element by its
``ID`` attribute. [3633]
- Instances in the votable tree now have better ``__repr__`` methods. [3639]
astropy.logger.py
^^^^^^^^^^^^^^^^^
- Added log levels (e.g., DEBUG, INFO, CRITICAL) to ``astropy.log`` [3947]
astropy.modeling
^^^^^^^^^^^^^^^^
- Added a new ``Parameter.validator`` interface for setting a validation
method on individual model parameters. See the ``Parameter``
documentation for more details. [3910]
- The projection classes that are named based on the 3-letter FITS
WCS projections (e.g. ``Pix2Sky_TAN``) now have aliases using
longer, more descriptive names (e.g. ``Pix2Sky_Gnomonic``).
[3583]
- All of the standard FITS WCS projection types have been
implemented in ``astropy.modeling.projections`` (by wrapping
WCSLIB). [3906]
- Added ``Sersic1D`` and ``Sersic2D`` model classes. [3889]
- Added the Voigt profile to existing models. [3901]
- Added ``bounding_box`` property and ``render_model`` function [3909]
astropy.nddata
^^^^^^^^^^^^^^
- Added ``block_reduce`` and ``block_replicate`` functions. [3453]
- ``extract_array`` now offers different options to deal with array
boundaries [3727]
- Added a new ``Cutout2D`` class to create postage stamp image cutouts
with optional WCS propagation. [3823]
astropy.stats
^^^^^^^^^^^^^
- Added ``sigma_lower`` and ``sigma_upper`` keywords to
``sigma_clip`` to allow for non-symmetric clipping. [3595]
- Added ``cenfunc``, ``stdfunc``, and ``axis`` keywords to
``sigma_clipped_stats``. [3792]
- ``sigma_clip`` automatically masks invalid input values (NaNs, Infs) before
performing the clipping [4051]
- Added the ``histogram`` routine, which is similar to ``np.histogram`` but
includes several additional options for automatic determination of optimal
histogram bins. Associated helper routines include ``bayesian_blocks``,
``friedman_bin_width``, ``scott_bin_width``, and ``knuth_bin_width``.
This functionality was ported from the astroML library. [3756]
- Added the ``bayesian_blocks`` routine, which implements a dynamic algorithm
for locating change-points in various time series. [3756]
- A new function ``poisson_conf_interval()`` was added to allow easy calculation
of several standard formulae for the error bars on the mean of a Poisson variable
estimated from a single sample.
astropy.table
^^^^^^^^^^^^^
- ``add_column()`` and ``add_columns()`` now have ``rename_duplicate``
option to rename new column(s) rather than raise exception when its name
already exists. [3592]
- Added ``Table.to_pandas`` and ``Table.from_pandas`` for converting to/from
pandas dataframes. [3504]
- Initializing a ``Table`` with ``Column`` objects no longer requires
that the column ``name`` attribute be defined. [3781]
- Added an ``info`` property to ``Table`` objects which provides configurable
summary information about the table and its columns. [3731]
- Added an ``info`` property to column classes (``Column`` or mixins). This
serves a dual function of providing configurable summary information about
the column, and acting as a manager of column attributes such as
name, format, or description. [3731]
- Updated table and column representation to use the ``dtype_info_name``
function for the dtype value. Removed the default "masked=False"
from the table representation. [3868, 3869]
- Updated row representation to be consistent with the corresponding
table representation for that row. Added HTML representation so a
row displays nicely in IPython notebook.
- Added a new table indexing engine allowing for the creation of
indices on one or more columns of a table using ``add_index``. These
indices enable new functionality such as searching for rows by value
using ``loc`` and ``iloc``, as well as increased performance for
certain operations. [3915, 4202]
- Added capability to include a structured array or recarray in a table
as a mixin column. This allows for an approximation of nested tables.
[3925]
- Added ``keep_byteorder`` option to ``Table.as_array()``. See the
"API Changes" section below. [4080]
- Added a new method ``Table.replace_column()`` to replace an existing
column with a new data column. [4090]
- Added a ``tableclass`` option to ``Table.pformat()`` to allow specifying
a list of CSS classes added to the HTML table. [4131]
- New CSS for jsviewer table [2917, 2982, 4174]
- Added a new ``Table.show_in_notebook`` method that shows an interactive view
of a Table (similar to ``Table.show_in_browser(jsviewer=True)``) in an
Python/Jupyter notebook. [4197]
- Added column alignment formatting for better pprint viewing
experience. [3644]
astropy.tests
^^^^^^^^^^^^^
- Added new test config options, ``config_dir`` and ``cache_dir`` (these
can be edited in ``setup.cfg`` or as extra command-line options to
py.test) for setting the locations to use for the Astropy config files
and download caches (see also the related ``set_temp_config/cache``
features added in ``astropy.config``). [3975]
astropy.time
^^^^^^^^^^^^
- Add support for FITS standard time strings. [3547]
- Allow the ``format`` attribute to be updated in place to change the
default representation of a ``Time`` object. [3673]
- Add support for shape manipulation (reshape, ravel, etc.). [3224]
- Add argmin, argmax, argsort, min, max, ptp, sort methods. [3681]
- Add ``Time.to_datetime`` method for converting ``Time`` objects to
timezone-aware datetimes. [4119, 4124]
astropy.units
^^^^^^^^^^^^^
- Added furlong to imperial units. [3529]
- Added mil to imperial units. [3716]
- Added stone to imperial units. [4192]
- Added Earth Mass (``M_earth``) and Jupiter mass (``M_jup``) to units [3907]
- Added support for functional units, in particular the logarithmic ones
``Magnitude``, ``Decibel``, and ``Dex``. [1894]
- Quantities now work with the unit support in matplotlib. See
:ref:`plotting-quantities`. [3981]
- Clarified imperial mass measurements and added pound force (lbf),
kilopound (kip), and pound per square inch (psi). [3409]
astropy.utils
^^^^^^^^^^^^^
- Added new ``OrderedDescriptor`` and ``OrderedDescriptorContainer`` utility
classes that make it easier to implement classes with declarative APIs,
wherein class-level attributes have an inherit "ordering" to them that is
specified by the order in which those attributes are defined in the class
declaration (by defining them using special descriptors that have
``OrderedDescriptor`` as a base class). See the API documentation for
these classes for more details. Coordinate frames and models now use this
interface. [3679]
- The ``get_pkg_data_*`` functions now take an optional ``package`` argument
which allows specifying any package to read package data filenames or
content out of, as opposed to only being able to use data from the package
that the function is called from. [4079]
- Added function ``dtype_info_name`` to the ``data_info`` module to provide
the name of a ``dtype`` for human-readable informational purposes. [3868]
- Added ``classproperty`` decorator--this is to ``property`` as
``classmethod`` is to normal instance methods. [3982]
- ``iers.open`` now handles network URLs, as well as local paths. [3850]
- The ``astropy.utils.wraps`` decorator now takes an optional
``exclude_args`` argument not shared by the standard library ``wraps``
decorator (as it is unique to the Astropy version's ability of copying
the wrapped function's argument signature). ``exclude_args`` allows
certain arguments on the wrapped function to be excluded from the signature
of the wrapper function. This is particularly useful when wrapping an
instance method as a function (to exclude the ``self`` argument). [4017]
- ``get_readable_fileobj`` can automatically decompress LZMA ('.xz')
files using the ``lzma`` module of Python 3.3+ or, when available, the
``backports.lzma`` package on earlier versions. [3667]
- The ``resolve_name`` utility now accepts any number of additional
positional arguments that are automatically dotted together with the
first ``name`` argument. [4083]
- Added ``is_url_in_cache`` for resolving paths to cached files via URLS
and checking if files exist. [4095]
- Added a ``step`` argument to the ``ProgressBar.map`` method to give
users control over the update frequency of the progress bar. [4191]
astropy.visualization
^^^^^^^^^^^^^^^^^^^^^
- Added a function / context manager ``quantity_support`` for enabling
seamless plotting of ``Quantity`` instances in matplotlib. [3981]
- Added the ``hist`` function, which is similar to ``plt.hist`` but
includes several additional options for automatic determination of optimal
histogram bins. This functionality was ported from the astroML library.
[3756]
astropy.wcs
^^^^^^^^^^^
- The included version of wcslib has been upgraded to 5.10. [3992, 4239]
The minimum required version of wcslib in the 4.x series remains 4.24.
The minimum required version of wcslib in the 5.x series is
5.8. Building astropy against a wcslib 5.x prior to 5.8
will raise an ``ImportError`` when ``astropy.wcs`` is imported.
The wcslib changes relevant to astropy are:
- The FITS headers returned by ``astropy.wcs.WCS.to_header`` and
``astropy.wcs.WCS.to_header_string`` now include values with
more precision. This will result in numerical differences in
your results if you convert ``astropy.wcs.WCS`` objects to FITS
headers and use the results.
- ``astropy.wcs.WCS`` now recognises the ``TPV``, ``TPD``,
``TPU``, ``DSS``, ``TNX`` and ``ZPX`` polynomial distortions.
- Added relaxation flags to allow ``PC0i_0ja``, ``PV0j_0ma``, and
``PS0j_0ma`` (i.e. with leading zeroes on the index).
- Tidied up error reporting, particularly relating to translating
status returns from lower-level functions.
- Changed output formatting of floating point values in
``to_header``.
- Enhanced text representation of ``WCS`` objects. [3604]
- The ``astropy.tests.helper`` module is now part of the public API (and has a
documentation page). This module was in previous releases of astropy,
but was not considered part of the public API until now. [3890]
- There is a new function ``astropy.online_help`` to search the
astropy documentation and display the result in a web
browser. [3642]
API changes
-----------
astropy.cosmology
^^^^^^^^^^^^^^^^^
- ``FLRW._tfunc`` and ``FLRW._xfunc`` are marked as deprecated. Users
should use the new public interfaces ``FLRW.lookback_time_integrand``
and ``FLRW.abs_distance_integrand`` instead. [3767]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- The default header line processing was made to be consistent with data line
processing in that it now ignores blank lines that may have whitespace
characters. Any code that explicitly specifies a ``header_start`` value
for parsing a file with blank lines in the header containing whitespace will
need to be updated. [2654]
astropy.io.fits
^^^^^^^^^^^^^^^
- The ``uint`` argument to ``fits.open`` is now True by default; that is,
arrays using the FITS unsigned integer convention will be detected, and
read as unsigned integers by default. A new config option for
``io.fits``, ``enable_uint``, can be changed to False to revert to the
original behavior of ignoring the ``uint`` convention unless it is
explicitly requested with ``uint=True``. [3916]
- The ``ImageHDU.NumCode`` and ``ImageHDU.ImgCode`` attributes (and same
for other classes derived from ``_ImageBaseHDU``) are deprecated. Instead,
the ``astropy.io.fits`` module-level constants ``BITPIX2DTYPE`` and
``DTYPE2BITPIX`` can be used. [3916]
astropy.modeling
^^^^^^^^^^^^^^^^
- Note: Comparisons of model parameters with array-like values now
yields a Numpy boolean array as one would get with normal Numpy
array comparison. Previously this returned a scalar True or False,
with True only if the comparison was true for all elements compared,
which could lead to confusing circumstances. [3912]
- Using ``model.inverse = None`` to reset a model's inverse to its
default is deprecated. In the future this syntax will explicitly make
a model not have an inverse (even if it has a default). Instead, use
``del model.inverse`` to reset a model's inverse to its default (if it
has a default, otherwise this just deletes any custom inverse that has
been assigned to the model and is still equivalent to setting
``model.inverse = None``). [4236]
- Adds a ``model.has_user_inverse`` attribute which indicates whether or not
a user has assigned a custom inverse to ``model.inverse``. This is just
for informational purposes, for example, for software that introspects
model objects. [4236]
- Renamed the parameters of ``RotateNative2Celestial`` and
``RotateCelestial2Native`` from ``phi``, ``theta``, ``psi`` to
``lon``, ``lat`` and ``lon_pole``. [3578]
- Deprecated the ``Pix2Sky_AZP.check_mu`` and ``Sky2Pix_AZP.check_mu``
methods (these were obscure "accidentally public" methods that were
probably not used by anyone). [3910]
- Added a phase parameter to the Sine1D model. [3807]
astropy.stats
^^^^^^^^^^^^^
- Renamed the ``sigma_clip`` ``sig`` keyword as ``sigma``. [3595]
- Changed the ``sigma_clip`` ``varfunc`` keyword to ``stdfunc``. [3595]
- Renamed the ``sigma_clipped_stats`` ``mask_val`` keyword to
``mask_value``. [3595]
- Changed the default ``iters`` keyword value to 5 in both the
``sigma_clip`` and ``sigma_clipped_stats`` functions. [4067]
astropy.table
^^^^^^^^^^^^^
- ``Table.as_array()`` always returns a structured array with each column in
the system's native byte order. The optional ``keep_byteorder=True``
option will keep each column's data in its original byteorder. [4080]
- ``Table.simple_table()`` now creates tables with int64 and float64 types
instead of int32 and float64. [4114]
- An empty table can now be initialized without a ``names`` argument as long
as a valid ``dtype`` argument (with names embedded) is supplied. [3977]
astropy.time
^^^^^^^^^^^^
- The ``astropy_time`` attribute and time format has been removed from the
public interface. Existing code that instantiates a new time object using
``format='astropy_time'`` can simply omit the ``format``
specification. [3857]
astropy.units
^^^^^^^^^^^^^
- Single-item ``Quantity`` instances with record ``dtype`` will now have
their ``isscalar`` property return ``True``, consistent with behaviour for
numpy arrays, where ``np.void`` records are considered scalar. [3899]
- Three changes relating to the FITS unit format [3993]:
- The FITS unit format will no longer parse an arbitrary number as a
scale value. It must be a power of 10 of the form ``10^^k``,
``10^k``, ``10+k``, ``10-k`` and ``10(k)``. [3993]
- Scales that are powers of 10 can be written out. Previously, any
non-1.0 scale was rejected.
- The ``*`` character is accepted as a separator between the scale
and the units.
- Unit formatter classes now require the ``parse`` and ``to_string``
methods are now required to be classmethods (and the formatter
classes themselves are assumed to be singletons that are not
instantiated). As unit formatters are mostly an internal implementation
detail this is not likely to affect any users. [4001]
- CGS E&M units are now defined separately from SI E&M units, and have
distinct physical types. [4255, 4355]
astropy.utils
^^^^^^^^^^^^^
- All of the ``get_pkg_data_*`` functions take an optional ``package``
argument as their second positional argument. So any code that previously
passed other arguments to these functions as positional arguments might
break. Use keyword argument passing instead to mitigate this. [4079]
- ``astropy.utils.iers`` now uses a ``QTable`` internally, which means that
the numerical columns are stored as ``Quantity``, with full support for
units. Furthermore, the ``ut1_utc`` method now returns a ``Quantity``
instead of a float or an array (as did ``pm_xy`` already). [3223]
- ``astropy.utils.iers`` now throws an ``IERSRangeError``, a subclass
of ``IndexError``, rather than a raw ``IndexError``. This allows more
fine-grained catching of situations where a ``Time`` is beyond the range
of the loaded IERS tables. [4302]
astropy.wcs
^^^^^^^^^^^
- When compiled with wcslib 5.9 or later, the FITS headers returned
by ``astropy.wcs.WCS.to_header`` and
``astropy.wcs.WCS.to_header_string`` now include values with more
precision. This will result in numerical differences in your
results if you convert ``astropy.wcs.WCS`` objects to FITS headers
and use the results.
- If NAXIS1 or NAXIS2 is not passed with the header object to
WCS.calc_footprint, a ValueError is raised. [3557]
Bug fixes
---------
astropy.constants
^^^^^^^^^^^^^^^^^
- The constants ``Ry`` and ``u`` are now properly used inside the
corresponding units. The latter have changed slightly as a result. [4229]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- Internally, ``coordinates`` now consistently uses the appropriate time
scales for using ERFA functions. [4302]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Fix a segfault in the fast C parser when one of the column headers
is empty [3545].
- Fix several bugs that prevented the fast readers from being used
when guessing the file format. Also improved the read trace
information to better understand format guessing. [4115]
- Fix an underlying problem that resulted in an uncaught TypeError
exception when reading a CDS-format file with guessing enabled. [4120]
astropy.modeling
^^^^^^^^^^^^^^^^
- ``Simplex`` fitter now correctly passes additional keywords arguments to
the scipy solver. [3966]
- The keyword ``acc`` (for accuracy) is now correctly accepted by
``Simplex``. [3966]
astropy.units
^^^^^^^^^^^^^
- The units ``Ryd`` and ``u`` are no longer hard-coded numbers, but depend
on the appropriate values in the ``constants`` module. As a result, these
units now imply slightly different conversions. [4229]
Other Changes and Additions
---------------------------
- The ``./setup.py test`` command is now implemented in the ``astropy.tests``
module again (previously its implementation had been moved into
astropy-helpers). However, that made it difficult to synchronize changes
to the Astropy test runner with changes to the ``./setup.py test`` UI.
astropy-helpers v1.1 and above will detect this implementation of the
``test`` command, when present, and use it instead of the old version that
was included in astropy-helpers (most users will not notice any difference
as a result of this change). [4020]
- The repr for ``Table`` no longer displays ``masked=False`` since tables
are not masked by default anyway. [3869]
- The version of ``PLY`` that ships with astropy has been updated to 3.6.
- WCSAxes is now required for doc builds. [4074]
- The migration guide from pre-v0.4 coordinates has been removed to avoid
cluttering the ``astropy.coordinates`` documentation with increasingly
irrelevant material. To see the migration guide, we recommend you simply look
to the archived documentation for previous versions, e.g.
https://docs.astropy.org/en/v1.0/coordinates/index.html#migrating-from-pre-v0-4-coordinates
[4203]
- In ``astropy.coordinates``, the transformations between GCRS, CIRS,
and ITRS have been adjusted to more logically reflect the order in
which they actually apply. This should not affect most coordinate
transformations, but may affect code that is especially sensitive to
machine precision effects that change when the order in which
transformations occur is changed. [4255]