The following is a quickstart guide to installing and running and the
latest version of
In short, the only setup required to run the JWST pipeline is to
jwst package into a
conda environment, and then to set correct
environment variables for accessing reference files through CRDS. From there,
the JWST pipeline can be run in a Python session or with
the command line interface, and
and other pipeline utilities can be imported
and used in a Python session.
1. Create a conda environment.
Python environments allow you to install different versions of packages and
their dependencies and keep them isolated from one another. While there are
several possible ways to achieve this (e.g
venv), we will use
conda in this
If you don’t already have
conda, please follow the
To create a conda environment specifically for the latest stable release of
jwst (in this example, called jwst_latest):
conda create --name jwst_latest python=3.10
This will create a new, (nearly) empty Python 3.10 environment in which you can
2. Install jwst from PyPi
Once you have created your conda environment, make sure it is active by doing:
conda activate jwst_latest
To install the last stable release of
jwst, and all its basic dependencies
(e.g numpy, stcal):
pip install jwst
For detailed installation instructions, including how to install the development
jwst from Github or how to install a previous released version, see
the Installation page.
3. Set environment variables for Calibration References Data System (CRDS)
CRDS is the system that manages the reference files needed to run the pipeline. Inside the STScI network, the pipeline works with default CRDS setup with no modifications. To run the pipeline outside the STScI network, CRDS must be configured by setting two environment variables:
export CRDS_PATH=$HOME/crds_cache export CRDS_SERVER_URL=https://jwst-crds.stsci.edu
CRDS_PATH is the directory on your filesystem that contains your local
CRDS cache, where reference files are accessed by the pipeline. The
CRDS_SERVER_URL variable specifies from which CRDS server reference files should
be obtained. For more information, see Reference Files, Parameter Files and CRDS.
4. Running the Pipeline
jwst installed and CRDS configured for JWST, you can now run the pipeline
and use JWST
For information on how to run the pipeline using the Python interface, see Running the JWST pipeline: Python Interface.
For information on how to run the pipeline using the command line interface, see Running the JWST pipeline: Command Line Interface.
For information on how to read and write data files with JWST