« Changelog History


astropy v4.0 Release Notes

Release Date: 2019-12-16 // over 4 years ago

  • 🆕 New Features

    astropy.config ^

    • The config and cache directories and the name of the config file are now customizable. This allows affiliated packages to put their configuration files in locations other than CONFIG_DIR/.astropy/. [#8237]

    astropy.constants

    • The version of constants can be specified via ScienceState in a way that constants and units will be consistent. [#8517]

    • 0️⃣ Default constants now use CODATA 2018 and IAU 2015 definitions. [#8761]

    • Constants can be pickled and unpickled. [#9377]

    astropy.convolution

    • 🛠 Fixed a bug [#9168] where having a kernel defined using unitless astropy quantity objects would result in a crash [#9300]

    astropy.coordinates

    • Changed coordinates.solar_system_ephemeris to also accept local files as input. The ephemeris can now be selected by either keyword (e.g. 'jpl', 'de430'), URL or file path. [#8767]

    • ➕ Added a cylindrical property to SkyCoord for shorthand access to a CylindricalRepresentation of the coordinate, as is already available for other common representations. [#8857]

    • 0️⃣ The default parameters for the Galactocentric frame are now controlled by a ScienceState subclass, galactocentric_frame_defaults. New parameter sets will be added to this object periodically to keep up with ever-improved measurements of the solar position and motion. [#9346]

    • Coordinate frame classes can now have multiple aliases by assigning a list of aliases to the class variable name. Any of the aliases can be used for attribute-style access or as the target of tranform_to() calls. [#8834]

    • ⚠ Passing a NaN to Distance no longer raises a warning. [#9598]

    astropy.cosmology

    • The pre-publication Planck 2018 cosmological parameters are included as the Planck2018_arXiv_v2 object. Please note that the values are preliminary, and when the paper is accepted a final version will be included as Planck18. [#8111]

    astropy.io.ascii ^

    • ✂ Removed incorrect warnings on Overflow when reading in FloatType 0.0 with use_fast_converter; synchronised IntType Overflow warning messages. [#9082]

    astropy.io.misc ^

    • 📇 Eliminate deprecated compatibility mode when writing Table metadata to HDF5 format. [#8899]

    • ➕ Add support for orthogonal polynomial models to ASDF. [#9107]

    astropy.io.fits ^

    • 🔄 Changed the fitscheck and fitsdiff script to use the argparse module instead of optparse. [#9148]

    • 👍 Allow writing of Table objects with Time columns that are also table indices to FITS files. [#8077]

    astropy.io.votable

    • 👌 Support VOTable version 1.4. The main addition is the new element, TIMESYS, which allows defining of metadata for temporal coordinates much like COOSYS defines metadata for celestial coordinates. [#9475]

    astropy.logger ^

    • ➕ Added a configuration option to specify the text encoding of the log file, with the default behavior being the platform-preferred encoding. [#9203]

    astropy.modeling ^

    • 📚 Major rework of modeling internals. See modeling documentation for details. <https://docs.astropy.org/en/v4.0.x/modeling/changes_for_4.html>_ . [#8769]

    • ➕ Add Tabular1D.inverse. [#9083]

    • Model.rename was changed to add the ability to rename Model.inputs and Model.outputs. [#9220]

    • 🆕 New function fix_inputs to generate new models from others by fixing specific inputs variable values to constants. [#9135]

    • inputs and outputs are now model instance attributes, and n_inputs and n_outputs are class attributes. Backwards compatible default values of inputs and outputs are generated. Model.inputs and Model.outputs are now settable which allows renaming them on per user case. [#9298]

    • ➕ Add a new model representing a sequence of rotations in 3D around an arbitrary number of axes. [#9369]

    • ➕ Add many of the numpy ufunc functions as models. [#9401]

    • ➕ Add BlackBody model. [#9282]

    • ➕ Add Drude1D model. [#9452]

    • ➕ Added analytical King model (KingProjectedAnalytic1D). [#9084]

    • ➕ Added Exponential1D and Logarithmic1D models. [#9351]

    astropy.nddata ^

    • ➕ Add a way for technically invalid but unambiguous units in a fits header to be parsed by CCDData. [#9397]

    • NDData now only accepts WCS objects which implement either the high, or low level APE 14 WCS API. All WCS objects are converted to a high level WCS object, so NDData.wcs now always returns a high level APE 14 object. Not all array slices are valid for wcs objects, so some slicing operations which used to work may now fail. [#9067]

    astropy.stats ^

    • The biweight_location, biweight_scale, and biweight_midvariance functions now allow for the axis keyword to be a tuple of integers. [#9309]

    • Added an ignore_nan option to the biweight_location, biweight_scale, and biweight_midvariance functions. [#9457]

    • A numpy MaskedArray can now be input to the biweight_location, biweight_scale, and biweight_midvariance functions. [#9466]

    • ✂ Removed the warning related to p0 in the Bayesian blocks algorithm. The caveat related to p0 is described in the docstring for Events. [#9567]

    astropy.table ^

    • 👌 Improved the implementation of Table.replace_column() to provide a speed-up of 5 to 10 times for wide tables. The method can now accept any input which convertible to a column of the correct length, not just Column subclasses. [#8902]

    • 👌 Improved the implementation of Table.add_column() to provide a speed-up of 2 to 10 (or more) when adding a column to tables, with increasing benefit as the number of columns increases. The method can now accept any input which is convertible to a column of the correct length, not just Column subclasses. [#8933]

    • 🔄 Changed the implementation of Table.add_columns() to use the new Table.add_column() method. In most cases the performance is similar or slightly faster to the previous implementation. [#8933]

    • MaskedColumn.data will now return a plain MaskedArray rather than the previous (unintended) masked_BaseColumn. [#8855]

    • ➕ Added depth-wise stacking dstack() in higher level table operation. It help will in stacking table column depth-wise. [#8939]

    • ➕ Added a new table equality method values_equal() which allows comparison table values to another table, list, or value, and returns an element-by-element equality table. [#9068]

    • ➕ Added new join_type='cartesian' option to the join operation. [#9288]

    • 👍 Allow adding a table column as a list of mixin-type objects, for instance t['q'] = [1 * u.m, 2 * u.m]. [#9165]

    • 👍 Allow table join() using any sortable key column (e.g. Time), not just ndarray subclasses. A column is considered sortable if there is a <column>.info.get_sortable_arrays() method that is implemented. [#9340]

    • ➕ Added Table.iterrows() for making row-wise iteration faster. [#8969]

    • 👍 Allow table to be initialized with a list of dict where the dict keys are not the same in every row. The table column names are the set of all keys found in the input data, and any missing key/value pairs are turned into missing data in the table. [#9425]

    • ⚠ Prevent unnecessary ERFA warnings when indexing by Time columns. [#9545]

    • ➕ Added support for sorting tables which contain non-mutable mixin columns (like SkyCoord) for which in-place item update is not allowed. [#9549]

    • Ensured that inserting np.ma.masked (or any other value with a mask) into a MaskedColumn causes a masked entry to be inserted. [#9623]

    • 🛠 Fixed a bug that caused an exception when initializing a MaskedColumn from another MaskedColumn that has a structured dtype. [#9651]

    ✅ astropy.tests ^

    • ✅ The plugin that handles the custom header in the test output has been moved to the pytest-astropy-header plugin package. See the README at <https://github.com/astropy/pytest-astropy-header>__ for information about using this new plugin. [#9214]

    astropy.time ^

    • ➕ Added a new time format ymdhms for representing times via year, month, day, hour, minute, and second attributes. [#7644]

    • TimeDelta gained a to_value method, so that it becomes easier to use it wherever a Quantity with units of time could be used. [#8762]

    • Made scalar Time and TimeDelta objects hashable based on JD, time scale, and location attributes. [#8912]

    • 👌 Improved error message when bad input is used to initialize a Time or TimeDelta object and the format is specified. [#9296]

    • 👍 Allow numeric time formats to be initialized with numpy longdouble, Decimal instances, and strings. One can select just one of these using in_subfmt. The output can be similarly set using out_subfmt. [#9361]

    • Introduce a new .to_value() method for Time (and adjusted the existing method for TimeDelta) so that one can get values in a given format and possible subfmt (e.g., to_value('mjd', 'str'). [#9361]

    • ⚠ Prevent unnecessary ERFA warnings when sorting Time objects. [#9545]

    astropy.timeseries

    • Adding epoch_phase, wrap_phase and normalize_phase keywords to TimeSeries.fold() to control the phase of the epoch and to return normalized phase rather than time for the folded TimeSeries. [#9455]

    astropy.uncertainty

    • 👍 Distribution was rewritten such that it deals better with subclasses. As a result, Quantity distributions now behave correctly with to methods yielding new distributions of the kind expected for the starting distribution, and to_value yielding NdarrayDistribution instances. [#9429, #9442]

    • The pdf_* properties that were used to calculate statistical properties of Distrubution instances were changed into methods. This allows one to pass parameters such as ddof to pdf_std and pdf_var (which generally should equal 1 instead of the default 0), and reflects that these are fairly involved calculations, not just "properties". [#9613]

    astropy.units ^

    • 👌 Support for unicode parsing. Currently supported are superscripts, Ohm, Ångström, and the micro-sign. [#9348]

    • Accept non-unit type annotations in @quantity_input. [#8984]

    • For numpy 1.17 and later, the new __array_function__ protocol is used to ensure that all top-level numpy functions interact properly with Quantity, preserving units also in operations like np.concatenate. [#8808]

    • ➕ Add equivalencies for surface brightness units to spectral_density. [#9282]

    astropy.utils ^

    • astropy.utils.data.download_file and astropy.utils.data.get_readable_fileobj now provides an http_headers keyword to pass in specific request headers for the download. It also now defaults to providing User-Agent: Astropy and Accept: */* headers. The default User-Agent value can be set with a new astropy.data.conf.default_http_user_agent configuration item. [#9508, #9564]

    • ➕ Added a new astropy.utils.misc.unbroadcast function which can be used to return the smallest array that can be broadcasted back to the initial array. [#9209]

    • The specific IERS Earth rotation parameter table used for time and coordinate transformations can now be set, either in a context or per session, using astropy.utils.iers.earth_rotation_table. [#9244]

    • Added export_cache and import_cache to permit transporting downloaded data to machines with no Internet connection. Several new functions are available to investigate the cache contents; e.g., check_download_cache can be used to confirm that the persistent cache has not become damaged. [#9182]

    • A new astropy.utils.iers.LeapSeconds class has been added to track leap seconds. [#9365]

    astropy.visualization

    • ➕ Added a new time_support context manager/function for making it easy to plot and format Time objects in Matplotlib. [#8782]

    • ➕ Added support for plotting any WCS compliant with the generalized (APE 14) WCS API with WCSAxes. [#8885, #9098]

    • 👌 Improved display of information when inspecting WCSAxes.coords. [#9098]

    • 👌 Improved error checking for the slices= argument to WCSAxes. [#9098]

    • ➕ Added support for more solar frames in WCSAxes. [#9275]

    • ➕ Add support for one dimensional plots to WCSAxes. [#9266]

    • Add a get_format_unit to wcsaxes.CoordinateHelper. [#9392]

    • 0️⃣ WCSAxes now, by default, sets a default label for plot axes which is the WCS physical type (and unit) for that axis. This can be disabled using the coords[i].set_auto_axislabel(False) or by explicitly setting an axis label. [#9392]

    • 🛠 Fixed the display of tick labels when plotting all sky images that have a coord_wrap less than 360. [#9542]

    astropy.wcs ^

    • Added a astropy.wcs.wcsapi.pixel_to_pixel function that can be used to transform pixel coordinates in one dataset with a WCS to pixel coordinates in another dataset with a different WCS. This function is designed to be efficient when the input arrays are broadcasted views of smaller arrays. [#9209]

    • Added a local_partial_pixel_derivatives function that can be used to determine a matrix of partial derivatives of each world coordinate with respect to each pixel coordinate. [#9392]

    • ⚡️ Updated wcslib to v6.4. [#9125]

    • 👌 Improved the SlicedLowLevelWCS class in astropy.wcs.wcsapi to avoid storing chains of nested SlicedLowLevelWCS objects when applying multiple slicing operations in turn. [#9210]

    • Added a wcs_info_str function to astropy.wcs.wcsapi to show a summary of an APE-14-compliant WCS as a string. [#8546, #9207]

    • ➕ Added two new optional attributes to the APE 14 low-level WCS: pixel_axis_names and world_axis_names. [#9156]

    • ⚡️ Updated the WCS class to now correctly take and return Time objects in the high-level APE 14 API (e.g. pixel_to_world. [#9376]

    • SlicedLowLevelWCS now raises IndexError rather than ValueError on an invalid slice. [#9067]

    • Added fit_wcs_from_points function to astropy.wcs.utils. Fits a WCS object to set of matched detector/sky coordinates. [#9469]

    • 🛠 Fix various bugs in SlicedLowLevelWCS when the WCS being sliced was one dimensional. [#9693]

    API Changes

    astropy.constants

    • Deprecated set_enabled_constants context manager. Use astropy.physical_constants and astropy.astronomical_constants. [#9025]

    astropy.convolution

    • ✂ Removed the deprecated keyword argument interpolate_nan from convolve_fft. [#9356]

    • ✂ Removed the deprecated keyword argument stddev from Gaussian2DKernel. [#9356]

    • 🗄 Deprecated and renamed MexicanHat1DKernel and MexicanHat2DKernel to RickerWavelet1DKernel and RickerWavelet2DKernel. [#9445]

    astropy.coordinates

    • ✂ Removed the recommended_units attribute from Representations; it was deprecated since 3.0. [#8892]

    • ✂ Removed the deprecated frame attribute classes, FrameAttribute, TimeFrameAttribute, QuantityFrameAttribute, CartesianRepresentationFrameAttribute; deprecated since 3.0. [#9326]

    • ✂ Removed longitude and latitude attributes from EarthLocation; deprecated since 2.0. [#9326]

    • The DifferentialAttribute for frame classes now passes through any input to the allowed_classes if only one allowed class is specified, i.e. this now allows passing a quantity in for frame attributes that use DifferentialAttribute. [#9325]

    • Removed the deprecated galcen_ra and galcen_dec attributes from the Galactocentric frame. [#9346]

    astropy.extern ^

    • ✂ Remove the bundled six module. [#8315]

    astropy.io.ascii ^

    • 👀 Masked column handling has changed, see astropy.table entry below. [#8789]

    astropy.io.misc ^

    • 👀 Masked column handling has changed, see astropy.table entry below. [#8789]

    • ✂ Removed deprecated usecPickle kwarg from fnunpickle and fnpickle. [#8890]

    astropy.io.fits ^

    • 👀 Masked column handling has changed, see astropy.table entry below. [#8789]

    • io.fits.Header has been made safe for subclasses for copying and slicing. As a result of this change, the private subclass CompImageHeader now always should be passed an explicit image_header. [#9229]

    • ✂ Removed the deprecated tolerance option in fitsdiff and io.fits.diff classes. [#9520]

    • ✂ Removed deprecated keyword arguments for CompImageHDU: compressionType, tileSize, hcompScale, hcompSmooth, quantizeLevel. [#9520]

    astropy.io.votable

    • 🔄 Changed pedantic argument to verify and change it to have three string-based options (ignore, warn, and exception) instead of just being a boolean. In addition, changed default to ignore, which means that warnings will not be shown by default when loading VO tables. [#8715]

    astropy.modeling ^

    • 👍 Eliminates support for compound classes (but not compound instances!) [#8769]

    • Slicing compound models more restrictive. [#8769]

    • Shape of parameters now includes n_models as dimension. [#8769]

    • Parameter instances now hold values instead of models. [#8769]

    • Compound model parameters now share instance and value with constituent models. [#8769]

    • No longer possible to assign slices of parameter values to model parameters attribute (it is possible to replace it with a complete array). [#8769]

    • 📚 Many private attributes and methods have changed (see documentation). [#8769]

    • 🗄 Deprecated BlackBody1D model and blackbody_nu and blackbody_lambda functions. [#9282]

    • The deprecated rotations.rotation_matrix_from_angle was removed. [#9363]

    • 🗄 Deprecated and renamed MexicanHat1D and MexicanHat2D to RickerWavelet1D and RickerWavelet2D. [#9445]

    • 🗄 Deprecated modeling.utils.ExpressionTree. [#9576]

    astropy.stats ^

    • ✂ Removed the iters keyword from sigma clipping stats functions. [#8948]

    • 📇 Renamed the a parameter to data in biweight stat functions. [#8948]

    • Renamed the a parameter to data in median_absolute_deviation. [#9011]

    • 📇 Renamed the conflevel keyword to confidence_level in poisson_conf_interval. Usage of conflevel now issues AstropyDeprecationWarning. [#9408]

    • 📇 Renamed the conf keyword to confidence_level in binom_conf_interval and binned_binom_proportion. Usage of conf now issues AstropyDeprecationWarning. [#9408]

    • Renamed the conf_lvl keyword to confidence_level in jackknife_stats. Usage of conf_lvl now issues AstropyDeprecationWarning. [#9408]

    astropy.table ^

    • The handling of masked columns in the Table class has changed in a way that may impact program behavior. Now a Table with masked=False may contain both Column and MaskedColumn objects, and adding a masked column or row to a table no longer "upgrades" the table and columns to masked. This means that tables with masked data which are read via Table.read() will now always have masked=False, though specific columns will be masked as needed. Two new table properties has_masked_columns and has_masked_values were added. See the Masking change in astropy 4.0 section within <https://docs.astropy.org/en/v4.0.x/table/masking.html>_ for details. [#8789]

    • Table operation functions such as join, vstack, hstack, etc now always return a table with masked=False, though the individual columns may be masked as necessary. [#8957]

    • Changed implementation of Table.add_column() and Table.add_columns() methods. Now it is possible add any object(s) which can be converted or broadcasted to a valid column for the table. Table.__setitem__ now just calls add_column. [#8933]

    • 🔄 Changed default table configuration setting replace_warnings from ['slice'] to []. This removes the default warning when replacing a table column that is a slice of another column. [#9144]

    • ✂ Removed the non-public method astropy.table.np_utils.recarray_fromrecords. [#9165]

    ✅ astropy.tests ^

    • 🗄 In addition to DeprecationWarning, now FutureWarning and ImportWarning would also be turned into exceptions. [#8506]

    • warnings_to_ignore_by_pyver option in enable_deprecations_as_exceptions() has changed. Please refer to API documentation. [#8506]

    • Default settings for warnings_to_ignore_by_pyver are updated to remove very old warnings that are no longer relevant and to add a new warning caused by pytest-doctestplus. [#8506]

    astropy.time ^

    • Time.get_ut1_utc now uses the auto-updated IERS_Auto by default, instead of the bundled IERS_B file. [#9226]

    • Time formats that do not use val2 now raise ValueError instead of silently ignoring a provided value. [#9373]

    • Custom time formats can now accept floating-point types with extended precision. Existing time formats raise exceptions rather than discarding extended precision through conversion to ordinary floating-point. [#9368]

    • Time formats (implemented in subclasses of TimeFormat) now have their input and output routines more thoroughly validated, making it more difficult to create damaged Time objects. [#9375]

    • The TimeDelta.to_value() method now can also take the format name as its argument, in which case the value will be calculated using the TimeFormat machinery. For this case, one can also pass a subfmt argument to retrieve the value in another form than float. [#9361]

    astropy.timeseries

    • Keyword midpoint_epoch is renamed to epoch_time. [#9455]

    astropy.uncertainty

    • 👍 Distribution was rewritten such that it deals better with subclasses. As a result, Quantity distributions now behave correctly with to methods yielding new distributions of the kind expected for the starting distribution, and to_value yielding NdarrayDistribution instances. [#9442]

    astropy.units ^

    • For consistency with ndarray, scalar Quantity.value will now return a numpy scalar rather than a python one. This should help keep track of precision better, but may lead to unexpected results for the rare cases where numpy scalars behave differently than python ones (e.g., taking the square root of a negative number). [#8876]

    • Removed the magnitude_zero_points module, which was deprecated in favour of astropy.units.photometric since 3.1. [#9353]

    • EquivalentUnitsList now has a _repr_html_ method to output a HTML table on a call to find_equivalent_units in Jupyter notebooks. [#9495]

    astropy.utils ^

    • download_file and related functions now accept a list of fallback sources, and they are able to update the cache at the user's request. [#9182]

    • 👍 Allow astropy.utils.console.ProgressBarOrSpinner.map and .map_unordered to take an argument multiprocessing_start_method to control how subprocesses are started; the different methods (fork, spawn, and forkserver) have different implications in terms of security, efficiency, and behavioural anomalies. The option is useful in particular for cross-platform testing because Windows supports only spawn while Linux defaults to fork. [#9182]

    • All operations that act on the astropy download cache now take an argument pkgname that allows one to specify which package's cache to use. [#8237, #9182]

    • ✂ Removed deprecated funcsigs and futures from astropy.utils.compat. [#8909]

    • ✂ Removed the deprecated astropy.utils.compat.numpy module. [#8910]

    • 🗄 Deprecated InheritDocstrings as it is natively supported by Sphinx 1.7 or higher. [#8881]

    • 🚚 Deprecated astropy.utils.timer module, which has been moved to astroquery.utils.timer and will be part of astroquery 0.4.0. [#9038]

    • 🗄 Deprecated astropy.utils.misc.set_locale function, as it is meant for internal use only. [#9471]

    • The implementation of data_info.DataInfo has changed (for a considerable performance boost). Generally, this should not affect simple subclasses, but because the class now uses __slots__ any attributes on the class have to be explicitly given a slot. [#8998]

    • IERS tables now use nan to mark missing values (rather than 1e20). [#9226]

    astropy.visualization

    • 0️⃣ The default clip value is now False in ImageNormalize. [#9478]

    • 0️⃣ The default clip value is now False in simple_norm. [#9698]

    • Infinite values are now excluded when calculating limits in ManualInterval and MinMaxInterval. They were already excluded in all other interval classes. [#9480]

    🐛 Bug Fixes

    astropy.convolution

    • Fixed nan_treatment='interpolate' option to convolve_fft to properly take into account fill_value. [#8122]

    astropy.coordinates

    • 0️⃣ The QuantityAttribute class now supports a None default value if a unit is specified. [#9345]

    • When Representation classes with the same name are defined, this no longer leads to a ValueError, but instead to a warning and the removal of both from the name registry (i.e., one either has to use the class itself to set, e.g., representation_type, or refer to the class by its fully qualified name). [#8561]

    astropy.io.fits ^

    • ⚠ Implemented skip (after warning) of header cards with reserved keywords in table_to_hdu. [#9390]

    • Add AstropyDeprecationWarning to read_table_fits when hdu= is selected, but does not match single present table HDU. [#9512]

    astropy.io.votable

    • ➕ Address issue #8995 by ignoring BINARY2 null mask bits for string values on parsing a VOTable. In this way, the reader should never create masked values for string types. [#9057]

    • ⚠ Corrected a spurious warning issued for the value attribute of the <OPTION> element in VOTable, as well as a test that erroneously treated the warning as acceptable. [#9470]

    astropy.nddata ^

    • Cutout2D will now get the WCS from its first argument if that argument has with WCS property. [#9492]

    • overlap_slices will now raise a ValueError if the input position contains any non-finite values (e.g. NaN or inf). [#9648]

    astropy.stats ^

    • 🛠 Fixed a bug where bayesian_blocks returned a single edge. [#8560]

    • 🛠 Fixed input data type validation for bayesian_blocks to work int arrays. [#9513]

    astropy.table ^

    • 🛠 Fix bug where adding a column consisting of a list of masked arrays was dropping the masks. [#9048]

    • Quantity columns with custom units can now round-trip via FITS tables, as long as the custom unit is enabled during reading (otherwise, the unit will become an UnrecognizedUnit). [#9015]

    • 🛠 Fix bug where string values could be truncated when inserting into a Column or MaskedColumn, or when adding or inserting a row containing string values. [#9559]

    astropy.time ^

    • 🛠 Fix bug when Time object is created with only masked elements. [#9624]

    • 🛠 Fix inaccuracy when converting between TimeDelta and datetime.timedelta. [#9679]

    astropy.units ^

    • ✅ Ensure that output from test functions of and comparisons between quantities can be stored into pre-allocated output arrays (using out=array) [#9273]

    astropy.utils ^

    • 0️⃣ For the default IERS_Auto table, which combines IERS A and B values, the IERS nutation parameters "dX_2000A" and "dY_2000A" are now also taken from the actual IERS B file rather than from the B values stored in the IERS A file. Any differences should be negligible for any practical application, but this may help exactly reproducing results. [#9237]

    astropy.visualization

    • Calling WCSAxes.set_axis_off() now correctly turns off drawing the Axes. [#9411]

    • 🛠 Fix incorrect transformation behavior in WCSAxes.plot_coord and correctly handle when input coordinates are not already in spherical representations. [#8927]

    • 🛠 Fixed ImageNormalize so that when it is initialized without data it will still use the input interval class. [#9698]

    • 🛠 Fixed ImageNormalize to handle input data with non-finite values. [#9698]

    astropy.wcs ^

    • 🛠 Fix incorrect value returned by wcsapi.HighLevelWCSWrapper.axis_correlation_matrix. [#9554]

    • 🛠 Fix NaN-masking of world coordinates when some but not all of the coordinates were flagged as invalid by WCSLIB. This occurred for example with WCS with >2 dimensions where two of the dimensions were celestial coordinates and pixel coordinates outside of the 'sky' were converted to world coordinates - previously all world coordinates were masked even if uncorrelated with the celestial axes, but this is no longer the case. [#9688]

    • 0️⃣ The default WCS to celestial frame mapping for world coordinate systems that specify TLON and TLAT coordinates will now return an ITRS frame with the representation class set to SphericalRepresentation. This fixes a bug that caused WCS.pixel_to_world to raise an error for such world coordinate systems. [#9609]

    • FITSWCSAPIMixin now returns tuples not lists from pixel_to_world and world_to_pixel. [#9678]

    Other Changes and Additions

    • 🔖 Versions of Python <3.6 are no longer supported. [#8955]

    • Matplotlib 2.1 and later is now required. [#8787]

    • 🔖 Versions of Numpy <1.16 are no longer supported. [#9292]

    • ⚡️ Updated the bundled CFITSIO library to 3.470. See cextern/cfitsio/docs/changes.txt for additional information. [#9233]

    • ⚡️ The bundled ERFA was updated to version 1.7.0. This is based on SOFA 20190722. This includes a fix to avoid precision loss for negative JDs, and also includes additional routines to allow updates to the leap-second table. [#9323, #9734]

    • ⚡️ The default server for the IERS data files has been updated to reflect long-term downtime of the canonical USNO server. [#9487, #9508]