Known Issues

While most bugs and issues are managed using the astropy issue tracker, this document lists issues that are too difficult to fix, may require some intervention from the user to workaround, or are due to bugs in other projects or packages.

Some docstrings can not be displayed in IPython < 0.13.2

Displaying long docstrings that contain Unicode characters may fail on some platforms in the IPython console (prior to IPython version 0.13.2):

In [1]: import astropy.units as u

In [2]: u.Angstrom?
ERROR: UnicodeEncodeError: 'ascii' codec can't encode character u'\xe5' in
position 184: ordinal not in range(128) []

This can be worked around by changing the default encoding to utf-8 by adding the following to your file:

import sys

Note that in general, this is not recommended, because it can hide other Unicode encoding bugs in your application. However, in general if your application does not deal with text processing and you just want docstrings to work, this may be acceptable.

The IPython issue:

Floating point precision issues on Python 2.6 on Microsoft Windows

When converting floating point numbers to strings on Python 2.6 on a Microsoft Windows platform, some of the requested precision may be lost.

The easiest workaround is to install Python 2.7.

The Python issue:

Failing logging tests when running the tests in IPython

When running the Astropy tests using astropy.test() in an IPython interpreter some of the tests in the astropy/tests/ fail. This is due to mutually incompatible behaviors in IPython and py.test, and is not due to a problem with the test itself or the feature being tested.


Numpy 1.4.x unreliable on 64-bit Ubuntu

As of Ubuntu 12.04 (and possibly earlier), the 1.4.x versions of numpy sometimes cause segmentation faults. This problem is not unique to Astropy, as the numpy tests themselves do not pass, but it does cause some Astropy functionality to fail.

The solution is to use a more recent version of Numpy.

mmap support for on GNU Hurd

On Hurd and possibly other platforms flush() on memory-mapped files is not implemented, so writing changes to a mmap’d FITS file may not be reliable and is thus disabled. Attempting to open a FITS file in writeable mode with mmap will result in a warning (and mmap will be disabled on the file automatically).


Crash on upgrading from Astropy 0.2 to a newer version

It is possible for installation of a new version of Astropy, or upgrading of an existing installation to crash due to not having permissions on the ~/.astropy/ directory (in your home directory) or some file or subdirectory in that directory. In particular this can occur if you installed Astropy as the root user (such as with sudo) at any point. This can manifest in several ways, but the most common is a traceback ending with ImportError: cannot import name config. To resolve this issue either run sudo chown -R <your_username> ~/.astropy or, if you don’t need anything in it you can blow it away with sudo rm -rf ~/.astropy.

See for example:

Color printing on Windows

Colored printing of log messages and other colored text does work in Windows but only when running in the IPython console. Colors are not currently supported in the basic Python command-line interpreter on Windows.