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astropy v5.0 Release Notes

Release Date: 2021-11-15 // over 2 years ago

  • 🆕 New Features

    astropy.convolution

    • ➕ Added dealiasing support to convolve_fft. [#11495]

    astropy.coordinates

    • ➕ Added missing coordinate transformations where the starting and ending frames are the same (i.e., loopback transformations). [#10909]

    • 👍 Allow negation, multiplication and division also of representations that include a differential (e.g., SphericalRepresentation with a SphericalCosLatDifferential). For all operations, the outcome is equivalent to transforming the representation and differential to cartesian, then operating on those, and transforming back to the original representation (except for UnitSphericalRepresentation, which will return a SphericalRepresentation if there is a scale change). [#11470]

    • RadialRepresentation.transform can work with a multiplication matrix only. All other matrices still raise an exception. [#11576]

    • transform methods are added to BaseDifferential and CartesianDifferential. All transform methods on Representations now delegate transforming differentials to the differential objects. [#11654]

    • ➕ Adds new HADec built-in frame with transformations to/from ICRS and CIRS. This frame complements AltAz to give observed coordinates (hour angle and declination) in the ITRS for an equatorially mounted telescope. [#11676]

    • SkyCoord objects now have a to_table() method, which allows them to be converted to a QTable. [#11743]

    astropy.cosmology

    • 📇 Cosmologies now store metadata in a mutable parameter meta. The initialization arguments name and meta are keyword-only. [#11542]

    • A new unit, redshift, is defined. It is a dimensionless unit to distinguish redshift quantities from other non-redshift values. For compatibility with dimensionless quantities the equivalency dimensionless_redshift is added. This equivalency is enabled by default. [#11786]

    • ➕ Add equality operator for comparing Cosmology instances. Comparison is done on all immutable fields (this excludes 'meta').

    Now the following will work:

    .. code-block:: python

      >>> from astropy.cosmology import Planck13, Planck18
  >>> Planck13 == Planck18
  False

  >>> Planck18 == Planck18
  True [#11813]

    • ➕ Added read/write methods to Cosmology using the Unified I/O registry. Now custom file format readers, writers, and format-identifier functions can be registered to read, write, and identify, respectively, Cosmology objects. Details are discussed in an addition to the docs. [#11948]

    • Added to_format/from_format methods to Cosmology using the Unified I/O registry. Now custom format converters and format-identifier functions can be registered to transform Cosmology objects. The transformation between Cosmology and dictionaries is pre-registered. Details are discussed in an addition to the docs. [#11998]

    • ➕ Added units module for defining and collecting cosmological units and equivalencies. [#12092]

    • Flat cosmologies are now set by a mixin class, FlatCosmologyMixin and its FLRW-specific subclass FlatFLRWMixin. All FlatCosmologyMixin are flat, but not all flat cosmologies are instances of FlatCosmologyMixin. As example, LambdaCDM may be flat (for the a specific set of parameter values), but FlatLambdaCDM will be flat.

    Cosmology parameters are now descriptors. When accessed from a class they transparently stores information, like the units and accepted equivalencies. On a cosmology instance, the descriptor will return the parameter value. Parameters can have custom getter methods.

    Cosmological equality is refactored to check Parameters (and the name) A new method, is_equivalent, is added to check Cosmology equivalence, so a FlatLambdaCDM and flat LambdaCDM are equivalent. [#12136]

    • Replaced z = np.asarray(z) with z = u.Quantity(z, u.dimensionless_unscaled).value in Cosmology methods. Input of values with incorrect units raises a UnitConversionError or TypeError. [#12145]

    • Cosmology Parameters allow for custom value setters. Values can be set once, but will error if set a second time. If not specified, the default setter is used, which will assign units using the Parameters units and equivalencies (if present). Alternate setters may be registered with Parameter to be specified by a str, not a decorator on the Cosmology. [#12190]

    • Cosmology instance conversion to dict now accepts keyword argument cls to determine dict type, e.g. OrderedDict. [#12209]

    • A new equivalency is added between redshift and the Hubble parameter and values with units of little-h. This equivalency is also available in the catch-all equivalency with_redshift. [#12211]

    • A new equivalency is added between redshift and distance -- comoving, lookback, and luminosity. This equivalency is also available in the catch-all equivalency with_redshift. [#12212]

    • Register Astropy Table into Cosmology's to/from_format I/O, allowing a Cosmology instance to be parsed from or converted to a Table instance. Also adds the __astropy_table__ method allowing Table(cosmology). [#12213]

    • The WMAP1 and WMAP3 are accessible as builtin cosmologies. [#12248]

    • Register Astropy Model into Cosmology's to/from_format I/O, allowing a Cosmology instance to be parsed from or converted to a Model instance. [#12269]

    • Register an ECSV reader and writer into Cosmology's I/O, allowing a Cosmology instance to be read from from or written to an ECSV file. [#12321]

    astropy.io.ascii ^

    • ➕ Added new way to specify the dtype for tables that are read: converters can specify column names with wildcards. [#11892]

    • ➕ Added a new astropy.io.ascii.Mrt class to write tables in the American Astronomical Society Machine-Readable Table format, including documentation and tests for the same. [#11897, #12301, #12302]

    • 🐎 When writing, the input data are no longer copied, improving performance. Metadata that might be changed, such as format and serialization information, is copied, hence users can continue to count on no changes being made to the input data. [#11919]

    astropy.io.misc ^

    • ➕ Add Parquet serialization of Tables with pyarrow, including metadata support and columnar access. [#12215]

    astropy.modeling ^

    • ➕ Added fittable spline models to modeling. [#11634]

    • 🔨 Extensive refactor of BoundingBox for better usability and maintainability. [#11930]

    • ➕ Added CompoundBoundingBox feature to ~astropy.modeling, which allows more flexibility in defining bounding boxes for models that are applied to images with many slices. [#11942]

    • 👌 Improved parameter support for astropy.modeling.core.custom_model created models. [#11984]

    • ➕ Added the following trigonometric models and linked them to their appropriate inverse models:

      • Cosine1D [#12158]
      • Tangent1D
      • ArcSine1D
      • ArcCosine1D
      • ArcTangent1D [#12185]

    astropy.table ^

    • ➕ Added a new method Table.update() which does a dictionary-style update of a Table by adding or replacing columns. [#11904]

    • 👍 Masked quantities are now fully supported in tables. This includes QTable automatically converting MaskedColumn instances to MaskedQuantity, and Table doing the reverse. [#11914]

    • Added new keyword arguments keys_left and keys_right to the table join function to support joining tables on key columns with different names. In addition the new keywords can accept a list of column-like objects which are used as the match keys. This allows joining on arbitrary data which are not part of the tables being joined. [#11954]

    • Formatting of any numerical values in the output of Table.info() and Column.info() has been improved. [#12022]

    • It is now possible to add dask arrays as columns in tables and have them remain as dask arrays rather than be converted to Numpy arrays. [#12219]

    • ➕ Added a new registry for mixin handlers, which can be used to automatically convert array-like Python objects into mixin columns when assigned to a table column. [#12219]

    astropy.time ^

    • Adds a new method earth_rotation_angle to calculate the Local Earth Rotation Angle. Also adjusts Local Sidereal Time for the Terrestrial Intermediate Origin (TIO) and adds a rigorous correction for polar motion. The TIO adjustment is approximately 3 microseconds per century from J2000 and the polar motion correction is at most about +/-50 nanoseconds. For models IAU1982 and IAU1994, no such adjustments are made as they pre-date the TIO concept. [#11680]

    astropy.timeseries

    • A custom binning scheme is now available in aggregate_downsample. It allows time_bin_start and time_bin_size to be arrays, and adds an optional time_bin_end. This scheme mirrors the API for BinnedTimeSeries. [#11266]

    astropy.units ^

    • Quantity gains a __class_getitem__ to create unit-aware annotations with the syntax Quantity[unit or physical_type, shape, numpy.dtype]. If the python version is 3.9+ or typing_extensions is installed, these are valid static type annotations. [#10662]

    • Each physical type is added to astropy.units.physical (e.g., physical.length or physical.electrical_charge_ESU). The attribute-accessible names (underscored, without parenthesis) also work with astropy.units.physical.get_physical_type. [#11691]

    • It is now possible to have quantities based on structured arrays in which the unit has matching structure, giving each field its own unit, using units constructed like Unit('AU,AU/day'). [#11775]

    • The milli- prefix has been added to astropy.units.Angstrom. [#11788]

    • ➕ Added attributes base, coords, and index and method copy() to QuantityIterator to match numpy.ndarray.flatiter. [#11796]

    • ➕ Added "angular frequency" and "angular velocity" as aliases for the "angular speed" physical type. [#11865]

    • ➕ Add light-second to units of length [#12128]

    astropy.utils ^

    • 📇 The astropy.utils.deprecated_renamed_argument() decorator now supports custom warning messages. [#12305]

    • The NaN-aware numpy functions such as np.nansum now work on Masked arrays, with masked values being treated as NaN, but without raising warnings or exceptions. [#12454]

    astropy.visualization

    • ➕ Added a feature so that SphericalCircle will accept center parameter as a SkyCoord object. [#11790]

    astropy.wcs ^

    • astropy.wcs.utils.obsgeo_to_frame has been added to convert the obsgeo coordinate array on astropy.wcs.WCS objects to an ITRS coordinate frame instance. [#11716]

    • 🛠 Updated bundled WCSLIB to version 7.7 with several bugfixes. [#12034]

    API Changes

    astropy.config ^

    • 0️⃣ update_default_config and ConfigurationMissingWarning are deprecated. [#11502]

    astropy.constants

    • Removed deprecated astropy.constants.set_enabled_constants context manager. [#12105]

    astropy.coordinates

    • Positions for the Moon using the 'builtin' ephemeris now use the new erfa.moon98 function instead of our own implementation of the Meeus algorithm. As this also corrects a misunderstanding of the frame returned by the Meeus, this improves the agreement with the JPL ephemeris from about 30 to about 6 km rms. [#11753]

    • ✂ Removed deprecated representation attribute from astropy.coordinates.BaseCoordinateFrame class. [#12257]

    • SpectralQuantity and SpectralCoord .to_value method can now be called without unit argument in order to maintain a consistent interface with Quantity.to_value [#12440]

    astropy.cosmology

    • z_at_value now works with arrays for all arguments (except func, verbose, and method). Consequently, coordinates.Distance.z can be used when Distance is an array. [#11778]

    • ✂ Remove deprecation warning and error remapping in Cosmology.clone. Now unknown arguments will raise a TypeError, not an AttributeError. [#11785]

    • The read/write and to/from_format Unified I/O registries are separated and apply only to Cosmology. [#12015]

    • Cosmology parameters in cosmology.parameters.py now have units, where applicable. [#12116]

    • 🗄 The function astropy.cosmology.utils.inf_like() is deprecated. [#12175]

    • The function astropy.cosmology.utils.vectorize_if_needed() is deprecated. A new function astropy.cosmology.utils.vectorize_redshift_method() is added as replacement. [#12176]

    • Cosmology base class constructor now only accepts arguments name and meta. Subclasses should add relevant arguments and not pass them to the base class. [#12191]

    astropy.io ^

    • When astropy raises an OSError because a file it was told to write already exists, the error message now always suggests the use of the overwrite=True argument. The wording is now consistent for all I/O formats. [#12179]

    astropy.io.ascii ^

    • ✂ Removed deprecated overwrite=None option for astropy.io.ascii.ui.write(). Overwriting existing files now only happens if overwrite=True. [#12171]

    astropy.io.fits ^

    • The internal class _CardAccessor is no longer registered as a subclass of the Sequence or Mapping ABCs. [#11923]

    • 🚚 The deprecated clobber argument will be removed from the astropy.io.fits functions in version 5.1, and the deprecation warnings now announce that too. [#12311]

    astropy.io.registry

    • The write function now is allowed to return possible content results, which means that custom writers could, for example, create and return an instance of some container class rather than a file on disk. [#11916]

    • 🔨 The registry functions are refactored into a class-based system. New Read-only, write-only, and read/write registries can be created. All functions accept a new argument registry, which if not specified, defaults to the global default registry. [#12015]

    astropy.io.votable

    • 🗄 Deprecated the pedantic keyword argument in the astropy.io.votable.table.parse function and the corresponding configuration setting. It has been replaced by the verify option. [#12129]

    astropy.modeling ^

    • 🔨 Refactored how astropy.modeling.Model handles model evaluation in order to better organize the code. [#11931]

    • ✂ Removed the following deprecated modeling features: astropy.modeling.utils.ExpressionTree class, astropy.modeling.functional_models.MexicanHat1D model, astropy.modeling.functional_models.MexicanHat2D model, astropy.modeling.core.Model.inputs setting in model initialize, astropy.modeling.core.CompoundModel.inverse setting in model initialize, and astropy.modeling.core.CompoundModel.both_inverses_exist() method. [#11978]

    • 🗄 Deprecated the AliasDict class in modeling.utils. [#12411]

    astropy.nddata ^

    • ⬇️ Removed block_reduce and block_replicate functions from nddata.utils. These deprecated functions in nddata.utils were moved to nddata.blocks. [#12288]

    astropy.stats ^

    • ✂ Removed the following deprecated features from astropy.stats:

      • conf argument for funcs.binom_conf_interval() and funcs.binned_binom_proportion(),
      • conflevel argument for funcs.poisson_conf_interval(), and
      • conf_lvl argument for jackknife.jackknife_stats(). [#12200]

    astropy.table ^

    • 🖨 Printing a Table now shows the qualified class name of mixin columns in the dtype header row instead of "object". This applies to all the Table formatted output methods whenever show_dtype=True is selected. [#11660]

    • The 'overwrite' argument has been added to the jsviewer table writer. Overwriting an existing file requires 'overwrite' to be True. [#11853]

    • The 'overwrite' argument has been added to the pandas table writers. Overwriting an existing file requires 'overwrite' to be True. [#11854]

    • The table join function now accepts only the first four arguments left, right, keys, and join_type as positional arguments. All other arguments must be supplied as keyword arguments. [#11954]

    • ➕ Adding a dask array to a Table will no longer convert that dask to a Numpy array, so accessing t['dask_column'] will now return a dask array instead of a Numpy array. [#12219]

    astropy.time ^

    • Along with the new method earth_rotation_angle, sidereal_time now accepts an EarthLocation as the longitude argument. [#11680]

    astropy.units ^

    • 🚚 Unit littleh and equivalency with_H0 have been moved to the cosmology module and are deprecated from astropy.units. [#12092]

    astropy.utils ^

    • astropy.utils.introspection.minversion() now uses importlib.metadata.version(). Therefore, its version_path keyword is no longer used and deprecated. This keyword will be removed in a future release. [#11714]

    • ⚡️ Updated utils.console.Spinner to better resemble the API of utils.console.ProgressBar, including an update() method and iterator support. [#11772]

    • Removed deprecated check_hashes in check_download_cache(). The function also no longer returns anything. [#12293]

    • Removed unused download_cache_lock_attempts configuration item in astropy.utils.data. Deprecation was not possible. [#12293]

    • Removed deprecated hexdigest keyword from import_file_to_cache(). [#12293]

    • 🔧 Setting remote_timeout configuration item in astropy.utils.data to 0 will no longer disable download from the Internet; Set allow_internet configuration item to False instead. [#12293]

    astropy.visualization

    • Removed deprecated imshow_only_kwargs keyword from imshow_norm. [#12290]

    astropy.wcs ^

    • Move complex logic from HighLevelWCSMixin.pixel_to_world and HighLevelWCSMixin.world_to_pixel into the helper functions astropy.wcs.wcsapi.high_level_api.high_level_objects_to_values and astropy.wcs.wcsapi.high_level_api.values_to_high_level_objects to allow reuse in other places. [#11950]

    🐛 Bug Fixes

    astropy.config ^

    • generate_config no longer outputs wrong syntax for list type. [#12037]

    astropy.constants

    • 🛠 Fixed a bug where an older constants version cannot be set directly after astropy import. [#12084]

    astropy.convolution

    • Passing an array argument for any Kernel1D or Kernel2D subclasses (with the exception of CustomKernel) will now raise a TypeError. [#11969]

    astropy.coordinates

    • If a Table containing a SkyCoord object as a column is written to a FITS, ECSV or HDF5 file then any velocity information that might be present will be retained. [#11750]

    • The output of SkyCoord.apply_space_motion() now always has the same differential type as the SkyCoord itself. [#11932]

    • 🛠 Fixed bug where Angle, Latitude and Longitude with NaN values could not be printed. [#11943]

    • 🛠 Fixed a bug with the transformation from PrecessedGeocentric to GCRS where changes in obstime, obsgeoloc, or obsgeovel were ignored. This bug would also affect loopback transformations from one PrecessedGeocentric frame to another PrecessedGeocentric frame. [#12152]

    • 🛠 Fixed a bug with the transformations between TEME and ITRS or between TEME and itself where a change in obstime was ignored. [#12152]

    • Avoid unnecessary transforms through CIRS for AltAz and HADec and use ICRS as intermediate frame for these transformations instead. [#12203]

    • 🛠 Fixed a bug where instantiating a representation with a longitude component could mutate input provided for that component even when copying is specified. [#12307]

    • Wrapping an Angle array will now ignore NaN values instead of attempting to wrap them, which would produce unexpected warnings/errors when working with coordinates and representations due to internal broadcasting. [#12317]

    astropy.cosmology

    • Dictionaries for in-built cosmology realizations are not altered by creating the realization and are also made immutable. [#12278]

    astropy.io.fits ^

    • Prevent zero-byte writes for FITS binary tables to speed up writes on the Lustre filesystem. [#11955]

    • Enable json.dump for FITS_rec with variable length (VLF) arrays. [#11957]

    • ➕ Add support for reading and writing int8 images [#11996]

    • Ensure header passed to astropy.io.fits.CompImageHDU does not need to contain standard cards that can be automatically generated, such as BITPIX and NAXIS. [#12061]

    • Fixed a bug where astropy.io.fits.HDUDiff would ignore the ignore_blank_cards keyword argument. [#12122]

    • Open uncompressed file even if extension says it's compressed [#12135]

    • 🛠 Fix the computation of the DATASUM in a CompImageHDU when the data is >1D. [#12138]

    • Reading files where the SIMPLE card is present but with an invalid format now issues a warning instead of raising an exception [#12234]

    • Convert UNDEFINED to None when iterating over card values. [#12310]

    astropy.io.misc ^

    • ⚡️ Update ASDF tag versions in ExtensionType subclasses to match ASDF Standard 1.5.0. [#11986]

    • 🛠 Fix ASDF serialization of model inputs and outputs and add relevant assertion to test helper. [#12381]

    • 🛠 Fix bug preventing ASDF serialization of bounding box for models with only one input. [#12385]

    astropy.io.votable

    • Now accepting UCDs containing phot.color. [#11982]

    astropy.modeling ^

    • ➕ Added Parameter descriptions to the implemented models which were missing. [#11232]

    • The separable property is now correctly set on models constructed with astropy.modeling.custom_model. [#11744]

    • 🛠 Minor bugfixes and improvements to modeling including the following:

      • Fixed typos and clarified several errors and their messages throughout modeling.
      • Removed incorrect try/except blocks around scipy code in convolution.py and functional_models.py.
      • Fixed Ring2D model's init to properly accept all combinations of r_in, r_out, and width.
      • Fixed bug in tau validator for the Logarithmic1D and Exponential1D models when using them as model sets.
      • Fixed copy method for Parameter in order to prevent an automatic KeyError, and fixed bool for Parameter so that it functions with vector values.
      • Removed unreachable code from Parameter, the _Tabular model, and the Drude1D model.
      • Fixed validators in Drude1D model so that it functions in a model set.
      • Removed duplicated code from polynomial.py for handing of domain and window.
      • Fixed the Pix2Sky_HEALPixPolar and Sky2Pix_HEALPixPolar modes so that their evaluate and inverse methods actually work without raising an error. [#12232]

    astropy.nddata ^

    • 📜 Ensure that the wcs= argument to NDData is always parsed into a high level WCS object. [#11985]

    astropy.stats ^

    • 🛠 Fixed a bug in sigma clipping where the bounds would not be returned for completely empty or masked data. [#11994]

    • Fixed a bug in biweight_midvariance and biweight_scale where output data units would be dropped for constant data and where the result was a scalar NaN. [#12146]

    astropy.table ^

    • Ensured that MaskedColumn.info is propagated in all cases, so that when tables are sliced, writing will still be as requested on info.serialize_method. [#11917]

    • ⚠ table.conf.replace_warnings and table.jsviewer.conf.css_urls configuration items now have correct 'string_list' type. [#12037]

    • 🛠 Fixed an issue where initializing from a list of dict-like rows (Mappings) did not work unless the row values were instances of dict. Now any object that is an instance of the more general collections.abc.Mapping will work. [#12417]

    astropy.uncertainty

    • Ensure that scalar QuantityDistribution unit conversion in ufuncs works properly again. [#12471]

    astropy.units ^

    • ➕ Add quantity support for scipy.special dimensionless functions erfinv, erfcinv, gammaln and loggamma. [#10934]

    • VOUnit.to_string output is now compliant with IVOA VOUnits 1.0 standards. [#11565]

    • Units initialization with unicode has been expanded to include strings such as 'M☉' and 'e⁻'. [#11827]

    • 📜 Give a more informative NotImplementedError when trying to parse a unit using an output-only format such as 'unicode' or 'latex'. [#11829]

    astropy.utils ^

    • Fixed a bug in get_readable_fileobj that prevented the unified file read interface from closing ASCII files. [#11809]

    • 🗄 The function astropy.utils.decorators.deprecated_attribute() no longer ignores its message, alternative, and pending arguments. [#12184]

    • Ensure that when taking the minimum or maximum of a Masked array, any masked NaN values are ignored. [#12454]

    astropy.visualization

    • 🚚 The tick labelling for radians has been fixed to remove a redundant .0 in the label for integer multiples of pi at 2pi and above. [#12221]

    • 🛠 Fix a bug where non-astropy.wcs.WCS WCS instances were not accepted in WCSAxes.get_transform. [#12286]

    • 🛠 Fix compatibility with Matplotlib 3.5 when using the grid_type='contours' mode for drawing grid lines. [#12447]

    astropy.wcs ^

    • Enabled SlicedLowLevelWCS.pixel_to_world_values to handle slices including non-int integers, e.g. numpy.int64. [#11980]

    Other Changes and Additions

    • 📄 In docstrings, Sphinx cross-reference targets now use intersphinx, even if the target is an internal link (link is now 'astropy:link). When built in Astropy these links are interpreted as internal links. When built in affiliate packages, the link target is set by the key 'astropy' in the intersphinx mapping. [#11690]

    • Made PyYaml >= 3.13 a strict runtime dependency. [#11903]

    • Minimum version of required Python is now 3.8. [#11934]

    • Minimum version of required Scipy is now 1.3. [#11934]

    • Minimum version of required Matplotlib is now 3.1. [#11934]

    • Minimum version of required Numpy is now 1.18. [#11935]

    • 🛠 Fix deprecation warnings with Python 3.10 [#11962]

    • 🔖 Speed up minversion() in cases where a module with a __version__ attribute is passed. [#12174]

    • astropy now requires packaging. [#12199]

    • ⚡️ Updated the bundled CFITSIO library to 4.0.0. When compiling with an external library, version 3.35 or later is required. [#12272]