========================
New Features
------------
astropy.constants
^^^^^^^^^^^^^^^^^
- Constants are now organized into version modules, with physical CODATA
constants in the ``codata2010`` and ``codata2014`` sub-modules,
and astronomical constants defined by the IAU in the ``iau2012`` and
``iau2015`` sub-modules. The default constants in ``astropy.constants``
in Astropy 2.0 have been updated from ``iau2012`` to ``iau2015`` and
from ``codata2010`` to ``codata2014``. The constants for 1.3 can be
accessed in the ``astropyconst13`` sub-module and the constants for 2.0
(the default in ``astropy.constants``) can also be accessed in the
``astropyconst20`` sub-module [6083]
- The GM mass parameters recommended by IAU 2015 Resolution B 3 have been
added as ``GM_sun``, ``GM_jup``, and ``GM_earth``, for the Sun,
Jupiter and the Earth. [6083]
astropy.convolution
^^^^^^^^^^^^^^^^^^^
- Major change in convolution behavior and keyword arguments. Additional
details are in the API section. [5782]
- Convolution with un-normalized and un-normalizable kernels is now possible.
[5782]
- Add a new argument, ``normalization_rtol``, to ``convolve_fft``, allowing
the user to specify the relative error tolerance in the normalization of
the convolution kernel. [5649, 5177]
- Models can now be convoluted using ``convolve`` or ``convolve_fft``,
which generates a regular compound model. [6015]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- Frame attributes set on ``SkyCoord`` are now always validated, and any
ndarray-like operation (like slicing) will also be done on those. [5751]
- Caching of all possible frame attributes was implemented. This greatly
speeds up many ``SkyCoord`` operations. [5703, 5751]
- A class hierarchy was added to allow the representation layer to store
differentials (i.e., finite derivatives) of coordinates. This is intended
to enable support for velocities in coordinate frames. [5871]
- ``replicate_without_data`` and ``replicate`` methods were added to
coordinate frames that allow copying an existing frame object with various
reference or copy behaviors and possibly overriding frame attributes. [6182]
- The representation class instances can now contain differential objects.
This is primarily useful for internal operations that will provide support
for transforming velocity components in coordinate frames. [6169]
- ``EarthLocation.to_geodetic()`` (and ``EarthLocation.geodetic``) now return
namedtuples instead of regular tuples. [6237]
- ``EarthLocation`` now has ``lat`` and ``lon`` properties (equivalent to, but
preferred over, the previous ``latitude`` and ``longitude``). [6237]
- Added a ``radial_velocity_correction`` method to ``SkyCoord`` to do compute
barycentric and heliocentric velocity corrections. [5752]
- Added a new ``AffineTransform`` class for coordinate frame transformations.
This class supports matrix operations with vector offsets in position or
any differential quantities (so far, only velocity is supported). The
matrix transform classes now subclass from the base affine transform.
[6218]
- Frame objects now have experimental support for velocity components. Most
frames default to accepting proper motion components and radial velocity,
and the velocities transform correctly for any transformation that uses
one of the ``AffineTransform``-type transformations. For other
transformations a finite-difference velocity transformation is available,
although it is not as numerically stable as those that use
``AffineTransform``-type transformations. [6219, 6226]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Allow to specify encoding in ``ascii.read``, only for Python 3 and with the
pure-Python readers. [5448]
- Writing latex tables with only a ``tabular`` environment is now possible by
setting ``latexdict['tabletyle']`` to ``None``. [6205]
- Allow ECSV format to support reading and writing mixin columns like
``Time``, ``SkyCoord``, ``Latitude``, and ``EarthLocation``. [6181]
astropy.io.fits
^^^^^^^^^^^^^^^
- Checking available disk space before writing out file. [5550, 4065]
- Change behavior to warn about units that are not FITS-compliant when
writing a FITS file but not when reading. [5675]
- Added absolute tolerance parameter when comparing FITS files. [4729]
- New convenience function ``printdiff`` to print out diff reports. [5759]
- Allow to instantiate a ``BinTableHDU`` directly from a ``Table`` object.
[6139]
astropy.io.misc
^^^^^^^^^^^^^^^
- YAML representer now also accepts numpy types. [6077]
astropy.io.registry
^^^^^^^^^^^^^^^^^^^
- New functions to unregister readers, writers, and identifiers. [6217]
astropy.modeling
^^^^^^^^^^^^^^^^
- Added ``SmoothlyBrokenPowerLaw1D`` model. [5656]
- Add ``n_submodels`` shared method to single and compound models, which
allows users to get the number of components of a given single (compound)
model. [5747]
- Added a ``name`` setter for instances of ``_CompoundModel``. [5741]
- Added FWHM properties to Gaussian and Moffat models. [6027]
- Added support for evaluating models and setting the results for inputs
outside the bounding_box to a user specified ``fill_value``. This
is controlled by a new optional boolean keyword ``with_bounding_box``. [6081]
- Added infrastructure support for units on parameters and during
model evaluation and fitting, added support for units on all
functional, power-law, polynomial, and rotation models where this
is appropriate. A new BlackBody1D model has been added.
[4855, 6183, 6204, 6235]
astropy.nddata
^^^^^^^^^^^^^^
- Added an image class, ``CCDData``. [6173]
astropy.stats
^^^^^^^^^^^^^
- Added ``biweight_midcovariance`` function. [5777]
- Added ``biweight_scale`` and ``biweight_midcorrelation``
functions. [5991]
- ``median_absolute_deviation`` and ``mad_std`` have ``ignore_nan`` option
that will use ``np.ma.median`` with nans masked out or ``np.nanmedian``
instead of ``np.median`` when computing the median. [5232]
- Implemented statistical estimators for Ripley's K Function. [5712]
- Added ``SigmaClip`` class. [6206]
- Added ``std_ddof`` keyword option to ``sigma_clipped_stats``.
[6066, 6207]
astropy.table
^^^^^^^^^^^^^
- Issue a warning when assigning a string value to a column and
the string gets truncated. This can occur because numpy string
arrays are fixed-width and silently drop characters which do not
fit within the fixed width. [5624, 5819]
- Added functionality to allow ``astropy.units.Quantity`` to be written
as a normal column to FITS files. [5910]
- Add support for Quantity columns (within a ``QTable``) in table
``join()``, ``hstack()`` and ``vstack()`` operations. [5841]
- Allow unicode strings to be stored in a Table bytestring column in
Python 3 using UTF-8 encoding. Allow comparison and assignment of
Python 3 ``str`` object in a bytestring column (numpy ``'S'`` dtype).
If comparison with ``str`` instead of ``bytes`` is a problem
(and ``bytes`` is really more logical), please open an issue on GitHub.
[5700]
- Added functionality to allow ``astropy.units.Quantity`` to be read
from and written to a VOtable file. [6132]
- Added support for reading and writing a table with mixin columns like
``Time``, ``SkyCoord``, ``Latitude``, and ``EarthLocation`` via the
ASCII ECSV format. [6181]
- Bug fix for ``MaskedColumn`` insert method, where ``fill_value`` attribute
was not being passed along to the copy of the ``MaskedColumn`` that was
returned. [7585]
astropy.tests
^^^^^^^^^^^^^
- ``enable_deprecations_as_exceptions`` function now accepts additional
user-defined module imports and warning messages to ignore. [6223, 6334]
astropy.units
^^^^^^^^^^^^^
- The ``astropy.units.quantity_input`` decorator will now convert the output to
the unit specified as a return annotation under Python 3. [5606]
- Passing a logarithmic unit to the ``Quantity`` constructor now returns the
appropriate logarithmic quantity class if ``subok=True``. For instance,
``Quantity(1, u.dex(u.m), subok=True)`` yields ``<Dex 1.0 dex(m)>``. [5928]
- The ``quantity_input`` decorator now accepts a string physical type in
addition to of a unit object to specify the expected input ``Quantity``'s
physical type. For example, ``u.quantity_input(x='angle')`` is now
functionally the same as ``u.quantity_input(x=u.degree)``. [3847]
- The ``quantity_input`` decorator now also supports unit checking for
optional keyword arguments and accepts iterables of units or physical types
for specifying multiple valid equivalent inputs. For example,
``u.quantity_input(x=['angle', 'angular speed'])`` or
``u.quantity_input(x=[u.radian, u.radian/u.yr])`` would both allow either
a ``Quantity`` angle or angular speed passed in to the argument ``x``.
[5653]
- Added a new equivalence ``molar_mass_amu`` between g/mol to
atomic mass units. [6040, 6113]
- ``Quantity`` has gained a new ``to_value`` method which returns the value
of the quantity in a given unit. [6127]
- ``Quantity`` now supports the ` operator for matrix multiplication that
was introduced in Python 3.5, for all supported versions of numpy. [6144]
- ``Quantity`` supports the new ``__array_ufunc__`` protocol introduced in
numpy 1.13. As a result, operations that involve unit conversion will be
sped up considerably (by up to a factor of two for costly operations such
as trigonometric ones). [2583]
astropy.utils
^^^^^^^^^^^^^
- Added a new ``dataurl_mirror`` configuration item in ``astropy.utils.data``
that is used to indicate a mirror for the astropy data server. [5547]
- Added a new convenience method ``get_cached_urls`` to ``astropy.utils.data``
for getting a list of the URLs in your cache. [6242]
astropy.wcs
^^^^^^^^^^^
- Upgraded the included wcslib to version 5.16. [6225]
The minimum required version of wcslib in is 5.14.
API Changes
-----------
astropy.analytic_functions
^^^^^^^^^^^^^^^^^^^^^^^^^^
- This entire sub-package is deprecated because blackbody has been moved to
``astropy.modeling.blackbody``. [6191]
astropy.convolution
^^^^^^^^^^^^^^^^^^^
- Major change in convolution behavior and keyword arguments.
``astropy.convolution.convolve_fft`` replaced ``interpolate_nan`` with
``nan_treatment``, and ``astropy.convolution.convolve`` received a new
``nan_treatment`` argument. ``astropy.convolution.convolve`` also no longer
double-interpolates interpolates over NaNs, although that is now available
as a separate ``astropy.convolution.interpolate_replace_nans`` function. See
`the backwards compatibility note
<https://docs.astropy.org/en/v2.0.16/convolution/index.html#a-note-on-backward-compatibility-pre-v2-0>`_
for more on how to get the old behavior (and why you probably don't want to.)
[5782]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- The ``astropy.coordinates.Galactic`` frame previously was had the cartesian
ordering 'w', 'u', 'v' (for 'x', 'y', and 'z', respectively). This was an
error and against the common convention. The 'x', 'y', and 'z' axes now
map to 'u', 'v', and 'w', following the right-handed ('u' points to
the Galactic center) convention. [6330]
- Removed deprecated ``angles.rotation_matrix`` and
``angles.angle_axis``. Use the routines in
``coordinates.matrix_utilities`` instead. [6170]
- ``EarthLocation.latitude`` and ``EarthLocation.longitude`` are now
deprecated in favor of ``EarthLocation.lat`` and ``EarthLocation.lon``.
They former will be removed in a future version. [6237]
- The ``FrameAttribute`` class and subclasses have been renamed to just contain
``Attribute``. For example, ``QuantityFrameAttribute`` is now
``QuantityAttribute``. [6300]
astropy.cosmology
^^^^^^^^^^^^^^^^^
- Cosmological models do not include any contribution from neutrinos or photons
by default -- that is, the default value of Tcmb0 is 0. This does not affect
built in models (such as WMAP or Planck). [6112]
astropy.io.fits
^^^^^^^^^^^^^^^
- Remove deprecated ``NumCode`` and ``ImgCode`` properties on FITS
``_ImageBaseHDU``. Use module-level constants ``BITPIX2DTYPE`` and
``DTYPE2BITPIX`` instead. [4993]
- ``comments`` meta key (which is ``io.ascii``'s table convention) is output
to ``COMMENT`` instead of ``COMMENTS`` header. Similarly, ``COMMENT``
headers are read into ``comments`` meta [6097]
- Remove compatibility code which forced loading all HDUs on close. The old
behavior can be used with ``lazy_load_hdus=False``. Because of this change,
trying to access the ``.data`` attribute from an HDU which is not loaded
now raises a ``IndexError`` instead of a ``ValueError``. [6082]
- Deprecated ``clobber`` keyword; use ``overwrite``. [6203]
- Add EXTVER column to the output of ``HDUList.info()``. [6124]
astropy.modeling
^^^^^^^^^^^^^^^^
- Removed deprecated ``Redshift`` model; Use ``RedshiftScaleFactor``. [6053]
- Removed deprecated ``Pix2Sky_AZP.check_mu`` and ``Pix2Sky_SZP.check_mu``
methods. [6170]
- Deprecated ``GaussianAbsorption1D`` model, as it can be better represented
by subtracting ``Gaussian1D`` from ``Const1D``. [6200]
- Added method ``sum_of_implicit_terms`` to ``Model``, needed when performing
a linear fit to a model that has built-in terms with no corresponding
parameters (primarily the ``1*x`` term of ``Shift``). [6174]
astropy.nddata
^^^^^^^^^^^^^^
- Removed deprecated usage of parameter ``propagate_uncertainties`` as a
positional keyword. [6170]
- Removed deprecated ``support_correlated`` attribute. [6170]
- Removed deprecated ``propagate_add``, ``propagate_subtract``,
``propagate_multiply`` and ``propagate_divide`` methods. [6170]
astropy.stats
^^^^^^^^^^^^^
- Removed the deprecated ``sig`` and ``varfunc`` keywords in the
``sigma_clip`` function. [5715]
- Added ``modify_sample_size`` keyword to ``biweight_midvariance``
function. [5991]
astropy.table
^^^^^^^^^^^^^
- In Python 3, when getting an item from a bytestring Column it is now
converted to ``str``. This means comparing a single item to a ``bytes``
object will always fail, and instead one must compare with a ``str``
object. [5700]
- Removed the deprecated ``data`` property of Row. [5729]
- Removed the deprecated functions ``join``, ``hstack``, ``vstack`` and
``get_groups`` from np_utils. [5729]
- Added ``name`` parameter to method ``astropy.table.Table.add_column`` and
``names`` parameter to method ``astropy.table.Table.add_columns``, to
provide the flexibility to add unnamed columns, mixin objects and also to
specify explicit names. Default names will be used if not
specified. [5996]
- Added optional ``axis`` parameter to ``insert`` method for ``Column`` and
``MaskedColumn`` classes. [6092]
astropy.units
^^^^^^^^^^^^^
- Moved ``units.cgs.emu`` to ``units.deprecated.emu`` due to ambiguous
definition of "emu". [4918, 5906]
- ``jupiterMass``, ``earthMass``, ``jupiterRad``, and ``earthRad`` no longer
have their prefixed units included in the standard units. If needed, they
can still be found in ``units.deprecated``. [5661]
- ``solLum``,``solMass``, and ``solRad`` no longer have their prefixed units
included in the standard units. If needed, they can still be found in
``units.required_by_vounit``, and are enabled by default. [5661]
- Removed deprecated ``Unit.get_converter``. [6170]
- Internally, astropy replaced use of ``.to(unit).value`` with the new
``to_value(unit)`` method, since this is somewhat faster. Any subclasses
that overwrote ``.to``, should also overwrite ``.to_value`` (or
possibly just the private ``._to_value`` method. (If you did this,
please let us know what was lacking that made this necessary!). [6137]
astropy.utils
^^^^^^^^^^^^^
- Removed the deprecated compatibility modules for Python 2.6 (``argparse``,
``fractions``, ``gzip``, ``odict``, ``subprocess``) [5975,6157,6164]
- Removed the deprecated ``zest.releaser`` machinery. [6282]
astropy.visualization
^^^^^^^^^^^^^^^^^^^^^
- Removed the deprecated ``scale_image`` function. [6170]
astropy.vo
^^^^^^^^^^
- Cone Search now issues deprecation warning because it is moved to
Astroquery 0.3.5 and will be removed from Astropy in a future version.
[5558, 5904]
- The ``astropy.vo.samp`` package has been moved to ``astropy.samp``, and no
longer supports HTTPS/SSL. [6201, 6213]
astropy.wcs
^^^^^^^^^^^
- Removed deprecated ``wcs.rotateCD``. [6170]
Bug Fixes
---------
astropy.convolution
^^^^^^^^^^^^^^^^^^^
- Major change in convolution behavior and keyword arguments:
``astropy.convolution.convolve`` was not performing normalized convolution
in earlier versions of astropy. [5782]
- Direct convolution previously implemented the wrong definition of
convolution. This error only affects *asymmetric* kernels. [6267]
astropy.coordinates
^^^^^^^^^^^^^^^^^^^
- The ``astropy.coordinates.Galactic`` frame had an incorrect ordering for the
'u', 'v', and 'w' cartesian coordinates. [6330]
- The ``astropy.coordinates.search_around_sky``,
``astropy.coordinates.search_around_3d``, and ``SkyCoord`` equivalent methods
now correctly yield an ``astropy.coordinates.Angle`` as the third return type
even if there are no matches (previously it returned a raw Quantity). [6347]
astropy.io.ascii
^^^^^^^^^^^^^^^^
- Fix an issue where the fast C-reader was dropping table comments for a
table with no data lines. [8274]
astropy.io.fits
^^^^^^^^^^^^^^^
- ``comments`` meta key (which is ``io.ascii``'s table convention) is output
to ``COMMENT`` instead of ``COMMENTS`` header. Similarly, ``COMMENT``
headers are read into ``comments`` meta [6097]
- Use more sensible fix values for invalid NAXISj header values. [5935]
- Close file on error to avoid creating a ``ResourceWarning`` warning
about an unclosed file. [6168, 6177]
astropy.modeling
^^^^^^^^^^^^^^^^
- Creating a compound model where one of the submodels is
a compound model whose parameters were changed now uses the
updated parameters and not the parameters of the original model. [5741]
- Allow ``Mapping`` and ``Identity`` to be fittable. [6018]
- Gaussian models now impose positive ``stddev`` in fitting. [6019]
- OrthoPolynomialBase (Chebyshev2D / Legendre2D) models were being evaluated
incorrectly when part of a compound model (using the parameters from the
original model), which in turn caused fitting to fail as a no-op. [6085]
- Allow ``Ring2D`` to be defined using ``r_out``. [6192]
- Make ``LinearLSQFitter`` produce correct results with fixed model
parameters and allow ``Shift`` and ``Scale`` to be fitted with
``LinearLSQFitter`` and ``LevMarLSQFitter``. [6174]
astropy.stats
^^^^^^^^^^^^^
- Allow to choose which median function is used in ``mad_std`` and
``median_absolute_deviation``. And allow to use these functions with
a multi-dimensional ``axis``. [5835]
- Fixed ``biweight_midvariance`` so that by default it returns a
variance that agrees with the standard definition. [5991]
astropy.table
^^^^^^^^^^^^^
- Fix a problem with vstack for bytes columns in Python 3. [5628]
- Fix QTable add/insert row for multidimensional Quantity. [6092]
astropy.time
^^^^^^^^^^^^
- Fixed the initial condition of ``TimeFITS`` to allow scale, FITS scale
and FITS realization to be checked and equated properly. [6202]
astropy.visualization
^^^^^^^^^^^^^^^^^^^^^
- Fixed a bug that caused the default WCS to return coordinates offset by
one. [6339]
astropy.vo
^^^^^^^^^^
- Fixed a bug in vo.samp when stopping a hub for which a lockfile was
not created. [6211]
Other Changes and Additions
---------------------------
- Numpy 1.7 and 1.8 are no longer supported. [6006]
- Python 3.3 is no longer supported. [6020]
- The bundled ERFA was updated to version 1.4.0. [6239]
- The bundled version of pytest has now been removed, but the
astropy.tests.helper.pytest import will continue to work properly.
Affiliated packages should nevertheless transition to importing pytest
directly rather than from astropy.tests.helper. This also means that
pytest is now a formal requirement for testing for both Astropy and
for affiliated packages. [5694]