========================
New Features
------------
astropy.constants
^^^^^^^^^^^^^^^^^
- New context manager ``set_enabled_constants`` to temporarily use an older
version. [7008]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- The ``Distance`` object now accepts ``parallax`` as a keyword in the
initializer, and supports retrieving a parallax (as an ``Angle``) via
the ``.parallax`` attributes. [6855]
- The coordinate frame classes (subclasses of ``BaseCoordinateFrame``) now
always have ``.velocity``, ``.proper_motion``, and ``.radial_velocity``
properties that provide shorthands to the full-space Cartesian velocity as
a ``CartesianDifferential``, the 2D proper motion as a ``Quantity``, and the
radial or line-of-sight velocity as a ``Quantity``. [6869]
- ``SkyCoord`` objects now support storing and transforming differentials - i.e.,
both radial velocities and proper motions. [6944]
- All frame classes now automatically get sensible representation mappings for
velocity components. For example, ``d_x``, ``d_y``, ``d_z`` are all
automatically mapped to frame component namse ``v_x``, ``v_y``, ``v_z``.
[6856]
- ``SkyCoord`` objects now support updating the position of a source given its
space motion and a new time or time difference. [6872]
- The frame classes now accept a representation class or differential class, or
string names for either, through the keyword arguments ``representation_type``
and ``differential_type`` instead of ``representation`` and
``differential_cls``. [6873]
- The frame classes (and ``SkyCoord``) now give more useful error messages when
incorrect attribute names are given. Instead of using the representation
attribute names, they use the frame attribute names. [7106]
- ``EarthLocation`` now has a method to compute the gravitational redshift due
due to solar system bodies. [6861, 6935]
- ``EarthLocation`` now has a ``get_gcrs`` convenience method to get the
location in GCRS coordinates. [6861, 6935]
astropy.io.fits
^^^^^^^^^^^^^^^
- Expanded the FITS ``Column`` interface to accept attributes pertaining to the FITS
World Coordinate System, which includes spatial(celestial) and time coordinates. [6359]
- Added ``ver`` attribute to set the ``EXTVER`` header keyword to ``ImageHDU``
and ``TableHDU``. [6454]
- The performance for reading FITS tables has been significantly improved,
in particular for cases where the tables contain one or more string columns
and when done through ``Table.read``. [6821]
- The performance for writing tables from ``Table.write`` has now been
significantly improved for tables containing one or more string columns. [6920]
- The ``Table.read`` now supports a ``memmap=`` keyword argument to control
whether or not to use memory mapping when reading the table. [6821]
- When reading FITS tables with ``fits.open``, a new keyword argument
``character_as_bytes`` can be passed - when set to `True`, character columns
are returned as Numpy byte arrays (Numpy type S) while when set to `False`,
the same columns are decoded to Unicode strings (Numpy type U) which uses more
memory. [6821]
- The ``table_to_hdu`` function and the ``BinTableHDU.from_columns`` and
``FITS_rec.from_columns`` methods now include a ``character_as_bytes``
keyword argument - if set to `True`, then when string columns are accessed,
byte columns will be returned, which can provide significantly improved
performance. [6920]
- Added support for writing and reading back a table which has "mixin columns"
such as ``SkyCoord`` or ``EarthLocation`` with no loss of information. [6912]
- Enable tab-completion for ``FITS_rec`` column names and ``Header`` keywords
with IPython 5 and later. [7071]
astropy.io.misc
^^^^^^^^^^^^^^^
- When writing to HDF5 files, the serialized metadata are now saved in a new
dataset, instead of the HDF5 dataset attributes. This allows for metadata of
any dimensions. [6304]
- Added support in HDF5 for writing and reading back a table which has "mixin
columns" such as ``SkyCoord`` or ``EarthLocation`` with no loss of
information. [7007]
- Add implementations of astropy-specific ASDF tag types. [6790]
- Add ASDF tag and schema for ICRSCoord. [6904]
astropy.modeling
^^^^^^^^^^^^^^^^
- Add unit support for tabular models. [6529]
- A ``deepcopy()`` method was added to models. [6515]
- Added units support to ``AffineTransformation``. [6853]
- Added ``is_separable`` function to modeling to test the
separability of a model. [6746]
- Added ``Model.separable`` property. It returns a boolean value or
``None`` if not set. [6746]
- Support masked array values in ``LinearLSQFitter`` (instead of silently
ignoring the mask). [6927]
astropy.stats
^^^^^^^^^^^^^
- Added false alarm probability computation to ``astropy.stats.LombScargle``
[6488]
- Implemented Kuiper functions in ``astropy.stats`` [3724, 6565]
astropy.table
^^^^^^^^^^^^^
- Added support for reading and writing ``astropy.time.Time`` Table columns
to and from FITS tables, to the extent supported by the FITS standard. [6176]
- Improved exception handling and error messages when column ``format``
attribute is incorrect for the column type. [6385]
- Allow to pass ``htmldict`` option to the jsviewer writer. [6551]
- Added new table operation ``astropy.table.setdiff`` that returns the set
difference of table rows for two tables. [6443]
- Added support for reading time columns in FITS compliant binary tables
as ``astropy.time.Time`` Table columns. [6442]
- Allowed to remove table rows through the ``__delitem__`` method. [5839]
- Added a new ``showtable`` command-line script to view binary or ASCII table
files. [6859]
- Added new table property ``astropy.table.Table.loc_indices`` that returns the
location of rows by indexes. [6831]
- Allow updating of table by indices through the property ``astropy.table.Table.loc``. [6831]
- Enable tab-completion for column names with IPython 5 and later. [7071]
- Allow getting and setting a table Row using multiple column names. [7107]
astropy.tests
^^^^^^^^^^^^^
- Split pytest plugins into separate modules. Move remotedata, openfiles,
doctestplus plugins to standalone repositories. [6384, 6606]
- When testing, astropy (or the package being tested) is now installed to
a temporary directory instead of copying the build. This allows
entry points to work correctly. [6890]
- The tests_require setting in setup.py now works properly when running
'python setup.py test'. [6892]
astropy.units
^^^^^^^^^^^^^
- Deprecated conversion of quantities to truth values. Currently, the expression
``bool(0 * u.dimensionless_unscaled)`` evaluates to ``True``. In the future,
attempting to convert a ``Quantity`` to a ``bool`` will raise ``ValueError``.
[6580, 6590]
- Modify the ``brightness_temperature`` equivalency to provide a surface
brightness equivalency instead of the awkward assumed-per-beam equivalency
that previously existed [5173, 6663]
- Support was added for a number of ``scipy.special`` functions. [6852]
astropy.utils
^^^^^^^^^^^^^
- The ``astropy.utils.console.ProgressBar.map`` class method now supports the
``ipython_widget`` option. You can now pass it both ``multiprocess=True`` and
``ipython_widget=True`` to get both multiprocess speedup and a progress bar
widget in an IPython Notebook. [6368]
- The ``astropy.utils.compat.funcsigs`` module has now been deprecated. Use the
Python 'inspect' module directly instead. [6598]
- The ``astropy.utils.compat.futures`` module has now been deprecated. Use the
Python 'concurrent.futures' module directly instead. [6598]
- ``JsonCustomEncoder`` is expanded to handle ``Quantity`` and ``UnitBase``.
[5471]
- Added a ``dcip_xy`` method to IERS that interpolates along the dX_2000A and
dY_2000A columns of the IERS table. Hence, the data for the CIP offsets is
now available for use in coordinate frame conversion. [5837]
- The functions ``matmul``, ``broadcast_arrays``, ``broadcast_to`` of the
``astropy.utils.compat.numpy`` module have been deprecated. Use the
NumPy functions directly. [6691]
- The ``astropy.utils.console.ProgressBar.map`` class method now returns
results in sequential order. Previously, if you set ``multiprocess=True``,
then the results could arrive in any arbitrary order, which could be a nasty
shock. Although the function will still be evaluated on the items in
arbitrary order, the return values will arrive in the same order in which the
input items were provided. The method is now a thin wrapper around
``astropy.utils.console.ProgressBar.map_unordered``, which preserves the old
behavior. [6439]
astropy.visualization
^^^^^^^^^^^^^^^^^^^^^
- Enable Matplotlib's subtraction shorthand syntax for composing and
inverting transformations for the ``WCSWorld2PixelTransform`` and
``WCSPixel2WorldTransform`` classes by setting ``has_inverse`` to ``True``.
In order to implement a unit test, also implement the equality comparison
operator for both classes. [6531]
- Added automatic hiding of axes labels when no tick labels are drawn on that
axis. This parameter can be configured with
``WCSAxes.coords[*].set_axislabel_visibility_rule`` so that labels are automatically
hidden when no ticks are drawn or always shown. [6774]
astropy.wcs
^^^^^^^^^^^
- Added a new function ``celestial_frame_to_wcs`` to convert from
coordinate frames to WCS (the opposite of what ``wcs_to_celestial_frame``
currently does. [6481]
- ``wcslib`` was updated to v 5.18. [7066]
API Changes
-----------
astropy.convolution
^^^^^^^^^^^^^^^^^^^
- ``Gaussian2DKernel`` now accepts ``x_stddev`` in place of ``stddev`` with
an option for ``y_stddev``, if different. It also accepts ``theta`` like
``Gaussian2D`` model. [3605, 6748]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- Deprecated ``recommended_units`` for representations. These were used to
ensure that any angle was presented in degrees in sky coordinates and
frames. This is more logically done in the frame itself. [6858]
- As noted above, the frame class attributes ``representation`` and
``differential_cls`` are being replaced by ``representation_type`` and
``differential_type``. In the next version, using ``representation`` will raise
a deprecation warning. [6873]
- Coordinate frame classes now can't be added to the frame transform graph if
they have frame attribute names that conflict with any component names. This
is so ``SkyCoord`` can uniquely identify and distinguish frame attributes from
frame components. [6871]
- Slicing and reshaping of ``SkyCoord`` and coordinate frames no longer passes
the new object through ``__init__``, but directly sets attributes on a new
instance. This speeds up those methods by an order of magnitude, but means
that any customization done in ``__init__`` is by-passed. [6941]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Allow ECSV files to be auto-identified by ``Table.read`` or
``Table.write`` based on the ``.ecsv`` file name suffix. In this case it
is not required to provide the ``format`` keyword. [6552]
astropy.io.fits
^^^^^^^^^^^^^^^
- Automatically detect and handle compression in FITS files that are opened by
passing a file handle to ``fits.open`` [6373]
- Remove the ``nonstandard`` checksum option. [6571]
astropy.io.misc
^^^^^^^^^^^^^^^
- When writing to HDF5 files, the serialized metadata are now saved in a new
dataset instead of the HDF5 dataset attributes. This allows for metadata of
any dimensions. [6304]
- Deprecated the ``usecPickle`` kwarg of ``fnunpickle`` and ``fnpickle`` as
it was needed only for Python2 usage. [6655]
astropy.io.votable
^^^^^^^^^^^^^^^^^^
- Add handling of ``tree.Group`` elements to ``tree.Resource``. Unified I/O
or conversion to astropy tables is not affected. [6262]
astropy.modeling
^^^^^^^^^^^^^^^^
- Removed deprecated ``GaussianAbsorption1D`` model.
Use ``Const1D - Gaussian1D`` instead. [6542]
- Removed the registry from modeling. [6706]
astropy.table
^^^^^^^^^^^^^
- When setting the column ``format`` attribute the value is now immediately
validated. Previously one could set to any value and it was only checked
when actually formatting the column. [6385]
- Deprecated the ``python3_only`` kwarg of the
``convert_bytestring_to_unicode`` and ``convert_unicode_to_bytestring``
methods it was needed only for Python2 usage. [6655]
- When reading in FITS tables with ``Table.read``, string columns are now
represented using Numpy byte (dtype ``S``) arrays rather than Numpy
unicode arrays (dtype ``U``). The ``Column`` class then ensures the
bytes are automatically converted to string as needed. [6821]
- When getting a table row using multiple column names, if one of the
names is not a valid column name then a ``KeyError`` exception is
now raised (previously ``ValueError``). When setting a table row,
if the right hand side is not a sequence with the correct length
then a ``ValueError`` is now raised (previously in certain cases
a ``TypeError`` was raised). [7107]
astropy.utils
^^^^^^^^^^^^^
- ``download_files_in_parallel`` now always uses ``cache=True`` to make the
function work on Windows. [6671]
astropy.visualization
^^^^^^^^^^^^^^^^^^^^^
- The Astropy matplotlib plot style has been deprecated. It will continue to
work in future but is no longer documented. [6991]
Bug Fixes
---------
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- Frame objects now use the default differential even if the representation is
explicitly provided as long as the representation provided is the same type as
the default representation. [6944]
- Coordinate frame classes now raise an error when they are added to the frame
transform graph if they have frame attribute names that conflict with any
component names. [6871]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Added support for reading very large tables in chunks to reduce memory
usage. [6458]
- Strip leading/trailing white-space from latex lines to avoid issues when
matching ``\begin{tabular}`` statements. This is done by introducing a new
``LatexInputter`` class to override the ``BaseInputter``. [6311]
astropy.io.fits
^^^^^^^^^^^^^^^
- Properly handle opening of FITS files from ``http.client.HTTPResponse`` (i.e.
it now works correctly when passing the results of ``urllib.request.urlopen``
to ``fits.open``). [6378]
- Fix the ``fitscheck`` script for updating invalid checksums, or removing
checksums. [6571]
- Fixed potential problems with the compression module [6732]
- Always use the 'D' format for floating point values in ascii tables. [6938]
astropy.table
^^^^^^^^^^^^^
- Fix getting a table row when using multiple column names (for example
``t[3]['a', 'b', 'c']``). Also fix a problem when setting an entire row:
if setting one of the right-hand side values failed this could result in
a partial update of the referenced parent table before the exception is
raised. [7107]
astropy.time
^^^^^^^^^^^^
- Initialization of ``Time`` instances with bytes or arrays with dtype ``S``
will now automatically attempt to decode as ASCII. This ensures ``Column``
instances with ASCII strings stored with dtype ``S`` can be used.
[6823, 6903]
astropy.units
^^^^^^^^^^^^^
- Fixed a bug that caused PLY files to not be generated correctly in Python 3.
[7174]
astropy.utils
^^^^^^^^^^^^^
- The ``deprecated`` decorator applied to a class will now modify the class
itself, rather than to create a class that just looks and behave like the
original. This is needed so that the Python 3 ``super`` without arguments
works for decorated classes. [6615]
- Fixed ``HomogeneousList`` when setting one item or a slice. [6773]
- Also check the type when creating a new instance of
``HomogeneousList``. [6773]
- Make ``HomogeneousList`` work with iterators and generators when creating the
instance, extending it, or using when setting a slice. [6773]
Other Changes and Additions
---------------------------
- Versions of Python <3.5 are no longer supported. [6556]
- Versions of Pytest <3.1 are no longer supported. [6419]
- Versions of Numpy <1.10 are no longer supported. [6593]
- The bundled CFITSIO was updated to version 3.41 [6477]
- ``analytic_functions`` sub-package is removed.
Use ``astropy.modeling.blackbody``. [6541]
- ``astropy.vo`` sub-package is removed. Use ``astropy.samp`` for SAMP and
``astroquery`` for VO cone search. [6540]
- The guide to setting up Emacs for code development was simplified, and
updated to recommend ``flycheck`` and ``flake8`` for syntax checks. [6692]
- The bundled version of PLY was updated to 3.10. [7174]