JWST Focal Plane Alignment Workflow

This repository contains codes and scripts that can be used for performing the Geometric Distortion Correction and the FGS-SI Alignment Calibration for JWST imaging detectors. Currently supported detectors are FGS, NIRCam, and NIRISS. Support for NIRSpec and MIRI may be included in a future version.

Installation

This package has some external dependencies and requires anaconda to be pre-installed. Assuming anaconda is installed in your system, follow the instructions below.

• Clone the jwst_fpa repository:

  git clone https://github.com/tonysohn/jwst_fpa.git

• Create a dedicated environment name fpa with the necessary dependencies:

  conda env create -f jwst_fpa/environment.yml -n fpa

• Activate the new environment:

  conda activate fpa

• All necessary packages should have been installed, and the scripts should be ready to be run. However, importing pysiaf may result in error in some cases. A quick and easy fix is to simply uninstall and reinstall lxml as follows:

  pip uninstall lxml

  pip install lxml

Usage

There are two main scripts and several supplemental codes/scripts included in this package. Below are quick descriptions for how to run the two main scripts.

• jwst_distortion.py - This script determines the geometric distortion solution for the JWST imaging detectors. The only essential configuration parameters required would be the data directory and whether the PSF is a nominal one or commissioning version (for OTE programs only, i.e., right after global alignment). Once the data_dir points to where the _cal.fits files are, open an ipython session and run the script: run jwst_distortion
• jwst_fpa.py - This is the script for the focal plane alignment workflow. This script has a separate configuration file named jwst_fpa_config.py. All configurations including the data directory should be specified in this file. Once the configuration file is ready, open an ipython session and run the script: run jwst_fpa