Requirements & Installation¶
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Recommended: Installing via AstroConda¶
For ease of installation, we recommend using AstroConda, an astronomy-optimized software distribution for scientific Python built on Anaconda. Install AstroConda according to their instructions, then activate the environment with:
$ source activate astroconda
(Note: if you named your environment something other than
astroconda, change the above command appropriately.)
Next, install WebbPSF (along with all its dependencies and required reference data) with:
(astroconda)$ conda install webbpsf
Updates to the latest version can be done as for any conda package:
(astroconda)$ conda update webbpsf
Installing with conda (but not AstroConda)¶
If you already use
conda, but do not want to install the full suite of STScI software, you can simply add the AstroConda channel and install WebbPSF as follows (creating a new environment named
$ conda config --add channels http://ssb.stsci.edu/astroconda $ conda create -n webbpsf-env webbpsf $ source activate webbpsf-env
Upgrading to the latest version is done with
conda update -n webbpsf-env --all.
You must install WebbPSF into a specific environment (e.g.
webbpsf-env); our conda package will not work if installed into the default “root” environment.
Installing with pip¶
WebbPSF and its underlying optical library POPPY may be installed from the Python Package Index in the usual manner for Python packages.
$ pip install --upgrade webbpsf [... progress report ...] Successfully installed webbpsf
pip install webbpsf only installs the program code. If you install via pip, you must manually download and install the data files, as described below.
To obtain source spectra for calculations, you should also follow installation instructions for synphot.
Installing or updating synphot¶
Stsynphot is an optional dependency, but is highly recommended. Stsynphot is best installed via AstroConda. Further installation instructions can be found in the synphot docs or a discussion in the POPPY docs.
Installing the Required Data Files¶
If you install via pip or manually, you must install the data files yourself. If you install via Conda, the data files are automatically installed, in which case you can skip this section.
Files containing such information as the JWST pupil shape, instrument throughputs, and aperture positions are distributed separately from WebbPSF. To run WebbPSF, you must download these files and tell WebbPSF where to find them using the
WEBBPSF_PATH environment variable.
Download the following file: webbpsf-data-0.9.0.tar.gz [approx. 240 MB]
webbpsf-data-0.9.0.tar.gzinto a directory of your choosing.
Set the environment variable
WEBBPSF_PATHto point to that directory. e.g.
for bash. (You will probably want to add this to your
You should now be able to successfully
import webbpsf in a Python session.
If you have previously installed the data files for an earlier version of WebbPSF, and then update to a newer version, the software may prompt you that you must download and install a new updated version of the data files.
For STScI Users Only: Users at STScI may access the required data files from the Central Storage network. Set the following environment variables in your
bash shell. (You will probably want to add this to your
export WEBBPSF_PATH="/grp/jwst/ote/webbpsf-data" export PYSYN_CDBS="/grp/hst/cdbs"
See the environment.yml specification file for the required package dependencies.
Required Python version: WebbPSF 1.0 and above require Python 3.7 or higher.
Recommended Python packages:
synphot enables the simulation of PSFs with proper spectral response to realistic source spectra. Without this, PSF fidelity is reduced. See above for installation instructions for synphot. Stsynphot is recommended for most users.
Optional Python packages:
Some calculations with POPPY can benefit from the optional packages psutil and pyFFTW, but these are not needed in general. See the POPPY installation docs for more details. These optional packages are only worth adding for speed improvements if you are spending substantial time running calculations.
Additional packages are needed for the optional use of GPUs to accelerate calculations. See the POPPY documentation.
Installing a pre-release version or contributing to WebbPSF development¶
To install the current development version of WebbPSF, you can use
pip to install directly from a
git repository. To install WebbPSF and POPPY from
git, uninstall any existing copies of WebbPSF and POPPY, then invoke pip as follows:
$ pip install -e git+https://github.com/spacetelescope/poppy.git#egg=poppy \ -e git+https://github.com/spacetelescope/webbpsf.git#egg=webbpsf
This will create directories
./src/webbpsf in your current directory containing the cloned repository. If you have commit access to the repository, you may want to clone via ssh with a URL like
git+ssh://firstname.lastname@example.org:spacetelescope/webbpsf.git. Documentation of the available options for installing directly from Git can be found in the pip documentation.
Remember to install the required data files, if you have not already installed them.