Full Changelog

0.2 (unreleased)

  • Nothing changed yet.

0.2b1 (2012-12-24)

New Features

This is a brief overview of the new features included in Astropy 0.2–please see the “What’s New” section of the documentation for more details.

  • astropy.coordinates

    • This new subpackage contains a representation of celestial coordinates, and provides a wide range of related functionality. While fully-functional, it is a work in progress and parts of the API may change in subsequent releases.
  • astropy.cosmology

    • Update to include cosmologies with variable dark energy equations of state. (This introduces some API incompatibilities with the older Cosmology objects).
    • Added parameters for relativistic species (photons, neutrinos) to the astropy.cosmology classes. The current treatment assumes that neutrinos are massless. [#365]
  • astropy.table I/O infrastructure for custom readers/writers implemented. [#305]

    • Added support for reading/writing HDF5 files [#461]
  • New astropy.time sub-package. [#332]

  • New astropy.units sub-package that includes a class for units (astropy.units.Unit) and scalar quantities that have units (astropy.units.Quantity). [#370, #445]

    This has the following effects on other sub-packages:

    • In astropy.wcs, the wcs.cunit list now takes and returns astropy.units.Unit objects. [#379]
    • In astropy.nddata, units are now stored as astropy.units.Unit objects. [#382]
    • In astropy.table, units on columns are now stored as astropy.units.Unit objects. [#380]
    • In astropy.constants, constants are now stored as astropy.units.Quantity objects. [#529]
  • astropy.io.ascii

    • Improved integration with the astropy.table Table class so that table and column metadata (e.g. keywords, units, description, formatting) are directly available in the output table object. The CDS, DAOphot, and IPAC format readers now provide this type of integrated metadata.
    • Changed to using astropy.table masked tables instead of NumPy masked arrays for tables with missing values.
    • Added SExtractor table reader to astropy.io.ascii [#420]
    • Removed the Memory reader class which was used to convert data input passed to the write function into an internal table. Instead write instantiates an astropy Table object using the data input to write.
    • Removed the NumpyOutputter as the output of reading a table is now always a Table object.
    • Removed the option of supplying a function as a column output formatter.
    • Added a new strip_whitespace keyword argument to the write function. This controls whether whitespace is stripped from the left and right sides of table elements before writing. Default is True.
    • Fixed a bug in reading IPAC tables with null values.
  • Added support for masked tables with missing or invalid data [#451]

  • astropy.wcs

    • From updating the the underlying wcslib 4.16:
      • When astropy.wcs.WCS constructs a default coordinate representation it will give it the special name “DEFAULTS”, and will not report “Found one coordinate representation”.

Other Changes and Additions

  • Astropy doc themes moved into astropy.sphinx to allow affiliated packages to access them.
  • Added expanded documentation for the astropy.cosmology sub-package. [#272]
  • Added option to disable building of “legacy” packages (pyfits, vo, etc.).
  • The value of the astronomical unit (au) has been updated to that adopted by IAU 2012 Resolution B2, and the values of the pc and kpc constants have been updated to reflect this. [#368]
  • Added links to the documentation pages to directly edit the documentation on GitHub. [#347]
  • Several updates merged from pywcs into astropy.wcs [#384]:
    • Improved the reading of distortion images.
    • Added a new option to choose whether or not to write SIP coefficients.
  • Added HTML representation of tables in IPython notebook [#409]
  • Rewrote CFITSIO-based backend for handling tile compression of FITS files. It now uses a standard CFITSIO instead of heavily modified pieces of CFITSIO as before. Astropy ships with its own copy of CFITSIO v3.30, but system packagers may choose instead to strip this out in favor of a system-installed version of CFITSIO. This corresponds to PyFITS ticket 169. [#318]
  • Moved astropy.config.data to astropy.utils.data and re-factored the I/O routines to separate out the generic I/O code that can be used to open any file or resource from the code used to access Astropy-related data. The ‘core’ I/O routine is now get_readable_fileobj, which can be used to access any local as well as remote data, supports caching, and can decompress gzip and bzip2 files on-the-fly. [#425]

Bug Fixes

  • astropy.io.fits
    • Improved handling of scaled images and pseudo-unsigned integer images in compressed image HDUs. They now work more transparently like normal image HDUs with support for the do_not_scale_image_data and uint options, as well as scale_back and save_backup. The .scale() method works better too. Corresponds to PyFITS ticket 88.
    • Permits non-string values for the EXTNAME keyword when reading in a file, rather than throwing an exception due to the malformatting. Added verification for the format of the EXTNAME keyword when writing. Corresponds to PyFITS ticket 96.
    • Added support for EXTNAME and EXTVER in PRIMARY HDUs. That is, if EXTNAME is specified in the header, it will also be reflected in the .name attribute and in fits.info(). These keywords used to be verboten in PRIMARY HDUs, but the latest version of the FITS standard allows them. Corresponds to PyFITS ticket 151.
    • HCOMPRESS can again be used to compress data cubes (and higher-dimensional arrays) so long as the tile size is effectively 2-dimensional. In fact, compatible tile sizes will automatically be used even if they’re not explicitly specified. Corresponds to PyFITS ticket 171.
    • Fixed a bug that could cause a deadlock in the filesystem on OSX when reading the data from certain types of FITS files. This only occurred when used in conjunction with Numpy 1.7. [#369]
    • Added support for the optional endcard parameter in the Header.fromtextfile() and Header.totextfile() methods. Although endcard=False was a reasonable default assumption, there are still text dumps of FITS headers that include the END card, so this should have been more flexible. Corresponds to PyFITS ticket 176.
    • Fixed a crash when running fitsdiff on two empty (that is, zero row) tables. Corresponds to PyFITS ticket 178.
    • Fixed an issue where opening a FITS file containing a random group HDU in update mode could result in an unnecessary rewriting of the file even if no changes were made. This corresponds to PyFITS ticket 179.
    • Fixed a crash when generating diff reports from diffs using the ignore_comments options. Corresponds to PyFITS ticket 181.
    • Fixed some bugs with WCS Paper IV record-valued keyword cards:
      • Cards that looked kind of like RVKCs but were not intended to be were over-permissively treated as such–commentary keywords like COMMENT and HISTORY were particularly affected. Corresponds to PyFITS ticket 183.
      • Looking up a card in a header by its standard FITS keyword only should always return the raw value of that card. That way cards containing values that happen to valid RVKCs but were not intended to be will still be treated like normal cards. Corresponds to PyFITS ticket 184.
      • Looking up a RVKC in a header with only part of the field-specifier (for example “DP1.AXIS” instead of “DP1.AXIS.1”) was implicitly treated as a wildcard lookup. Corresponds to PyFITS ticket 184.
    • Fixed a crash when diffing two FITS files where at least one contains a compressed image HDU which was not recognized as an image instead of a table. Corresponds to PyFITS ticket 187.
    • Fixed a bug where opening a file containing compressed image HDUs in ‘update’ mode and then immediately closing it without making any changes caused the file to be rewritten unnecessarily.
    • Fixed two memory leaks that could occur when writing compressed image data, or in some cases when opening files containing compressed image HDUs in ‘update’ mode.
    • Fixed a bug where ImageHDU.scale(option='old') wasn’t working at all–it was not restoring the image to its original BSCALE and BZERO values.
    • Fixed a bug when writing out files containing zero-width table columns, where the TFIELDS keyword would be updated incorrectly, leaving the table largely unreadable.
    • Fixed a minor string formatting issue.
    • Fixed bugs in the backwards compatibility layer for the CardList.index and CardList.count methods. Corresponds to PyFITS ticket 190.
    • Improved __repr__ and text file representation of cards with long values that are split into CONTINUE cards. Corresponds to PyFITS ticket 193.
    • Fixed a crash when trying to assign a long (> 72 character) value to blank (‘’) keywords. This also changed how blank keywords are represented–there are still exactly 8 spaces before any commentary content can begin; this may affect the exact display of header cards that assumed there could be fewer spaces in a blank keyword card before the content begins. However, the current approach is more in line with the requirements of the FITS standard. Corresponds to PyFITS ticket 194.
  • astropy.io.votable
    • The Table class now maintains a single array object which is a Numpy masked array. For variable-length columns, the object that is stored there is also a Numpy masked array.
    • Changed the pedantic configuration option to be False by default due to the vast proliferation of non-compliant VO Tables. [#296]
    • Renamed astropy.io.vo to astropy.io.votable.
  • astropy.table
    • Added a workaround for an upstream bug in Numpy 1.6.2 that could cause a maximum recursion depth RuntimeError when printing table rows. [#341]
  • astropy.wcs
    • Updated to wcslib 4.15 [#418]
    • Fixed a problem with handling FITS headers on locales that do not use dot as a decimal separator. This required an upstream fix to wcslib which is included in wcslib 4.14. [#313]
  • Fixed some tests that could fail due to missing/incorrect logging configuration–ensures that tests don’t have any impact on the default log location or contents. [#291]
  • Various minor documentation fixes [#293 and others]
  • Fixed a bug where running the tests with the py.test command still tried to replace the system-installed pytest with the one bundled with Astropy. [#454]

0.1 (2012-06-19)

  • Initial release.