Astropy has the following strict requirements:
Astropy also depends on other packages for optional features:
However, note that these only need to be installed if those particular features are needed. Astropy will import even if these dependencies are not installed.
To install Astropy with pip, simply run:
pip install --no-deps astropy
You will need a C compiler (e.g. gcc or clang) to be installed (see Building from source below) for the installation to succeed.
The --no-deps flag is optional, but highly recommended if you already have Numpy installed, since otherwise pip will sometimes try to “help” you by upgrading your Numpy installation, which may not always be desired.
If you get a PermissionError this means that you do not have the required administrative access to install new packages to your Python installation. In this case you may consider using the --user option to install the package into your home directory. You can read more about how to do this in the pip documentation.
Alternatively, if you intend to do development on other software that uses Astropy, such as an affiliated package, consider installing Astropy into a virtualenv.
Do not install Astropy or other third-party packages using sudo unless you are fully aware of the risks.
Binary installers are available on Windows for Python 2.6, 2.7, 3.1, and 3.2 at PyPI.
The easiest way to test your installed version of astropy is running correctly is to use the astropy.test() function:
import astropy astropy.test()
The tests should run and print out any failures, which you can report at the Astropy issue tracker.
You will need a compiler suite and the development headers for Python and Numpy in order to build Astropy. On Linux, using the package manager for your distribution will usually be the easiest route, while on MacOS X you will need the XCode command line tools.
The instructions for building Numpy from source are also a good resource for setting up your environment to build Python packages.
You will also need Cython installed to build from source, unless you are installing a numbered release. (The releases packages have the necessary C files packaged with them, and hence do not require Cython.)
If you are using MacOS X, you will need to the XCode command line tools. One way to get them is to install XCode. If you are using OS X 10.7 (Lion) or later, you must also explicitly install the command line tools. You can do this by opening the XCode application, going to Preferences, then Downloads, and then under Components, click on the Install button to the right of Command Line Tools. Alternatively, on 10.7 (Lion) or later, you do not need to install XCode, you can download just the command line tools from https://developer.apple.com/downloads/index.action (requires an Apple developer account).
The latest development version of Astropy can be cloned from github using this command:
git clone git://github.com/astropy/astropy.git
If you wish to participate in the development of Astropy, see Developer Documentation. This document covers only the basics necessary to install Astropy.
Astropy uses the Python distutils framework for building and installing and requires the distribute extension–the later is automatically downloaded when running python setup.py if it is not already provided by your system.
To build Astropy (from the root of the source tree):
python setup.py build
To install Astropy (from the root of the source tree):
python setup.py install
If you get an error mentioning that you do not have the correct permissions to install Astropy into the default site-packages directory, you can try installing with:
python setup.py install --user
which will install into a default directory in your home directory.
The Astropy source ships with the C source code of a number of libraries. By default, these internal copies are used to build Astropy. However, if you wish to use the system-wide installation of one of those libraries, you can pass one or more of the --use-system-X flags to the setup.py build command.
For example, to build Astropy using the system libexpat, use:
python setup.py build --use-system-expat
To build using all of the system libraries, use:
python setup.py build --use-system-libraries
To see which system libraries Astropy knows how to build against, use:
python setup.py build --help
As with all distutils commandline options, they may also be provided in a setup.cfg in the same directory as setup.py. For example, to use the system libexpat, add the following to the setup.cfg file:
If upon running the setup.py script you get a message like
The required version of setuptools (>=0.9.8) is not available, and can’t be installed while this script is running. Please install a more recent version first, using ‘easy_install -U setuptools’.
(Currently using setuptools 0.6c11 (/path/to/setuptools-0.6c11-py2.7.egg))
this is because you have a very outdated version of the setuptools package which is used to install Python packages. Normally Astropy will bootstrap a newer version of setuptools via the network, but setuptools suggests that you first uninstall the old version (the easy_install -U setuptools command). However, in the likely case that your version of setuptools was installed by an OS system package (on Linux check your package manager like apt or yum for a package called python-setuptools to be user). In this case trying to uninstall with easy_install and without using sudo may not work, or may leave your system package in an inconsistent state.
As the best course of action at this point depends largely on the individual system and how it is configured, if you are not sure yourself what do please ask on the Astropy mailing list.
This is a common issue with Windows installers for Python packages that do not support the new User Access Control (UAC) framework added in Windows Vista and later. In particular, when a Python is installed “for all users” (as opposed to for a single user) it adds entries for that Python installation under the HKEY_LOCAL_MACHINE (HKLM) hierarchy and not under the HKEY_CURRENT_USER (HKCU) hierarchy. However, depending on your UAC settings, if the Astropy installer is not executed with elevated privileges it will not be able to check in HKLM for the required information about your Python installation.
In short: If you encounter this problem it’s because you need the appropriate entries in the Windows registry for Python. You can download this script and execute it with the same Python as the one you want to install Astropy into. For example to add the missing registry entries to your Python 2.7:
This feature is still experimental, and you may run into unexpected issues with other packages, so we strongly recommend simply updating your code to use Astropy if possible, rather than rely on these compatibility packages.
Optionally, it is possible to install ‘compatibility’ packages that emulate the behavior of previous packages that have now been incorporated into Astropy. These are:
If you build Astropy with:
python setup.py build --enable-legacy python setup.py install
python setup.py install --enable-legacy
then you will be able to import these modules from your scripts as if the original packages had been installed. Using:
import pyfits import vo import pywcs
will then be equivalent to:
from astropy.io import fits as pyfits from astropy.io import vo from astropy import wcs as pywcs
In order to install the compatibility packages none of the original packages should be present.
If you are interested in testing out existing code with Astropy without modifying the import statements, but don’t want to uninstall existing packages, you can use virtualenv to set up a clean environment.
Building the documentation is in general not necessary unless you are writing new documentation or do not have internet access, because the latest (and archive) versions of astropy’s documentation should be available at docs.astropy.org .
Building the documentation requires the Astropy source code and some additional packages:
Sphinx also requires a reasonably modern LaTeX installation to render equations. Per the Sphinx documentation, for the TexLive distribution the following packages are required to be installed:
For other LaTeX distributions your mileage may vary. To build the PDF documentation using LaTeX, the fonts-extra TexLive package or the inconsolata CTAN package are also required.
There are two ways to build the Astropy documentation. The most straightforward way is to execute the command (from the astropy source directory):
python setup.py build_sphinx
The documentation will be built in the docs/_build/html directory, and can be read by pointing a web browser to docs/_build/html/index.html.
The LaTeX documentation can be generated by using the command:
python setup.py build_sphinx -b latex
The LaTeX file Astropy.tex will be created in the docs/_build/latex directory, and can be compiled using pdflatex.
The above method builds the API documentation from the source code. Alternatively, you can do:
cd docs make html
And the documentation will be generated in the same location, but using the installed version of Astropy.