imSim is a software package that simulates the LSST telescope and survey. It produces simulated images from the 3.25 Gigapixel camera which are suitable to be processed through the LSST Data Management pipeline. imSim takes as an input a catalog of astronomical sources along with information about how the light is distorted on the way to Earth including lensing and extinction information. The images which are produced include the systematic effects of the atmosphere, optics and sensors on the observed PSF.
imSim calls the GalSim library for astronomical object rendering and is designed to be used inside of the LSST Data Management and LSST Simulation Group software environment. It is not a stand alone program. It requires a working LSST software stack to build and run.
Communication with the imSim development team should take place through the imSim GitHub repository which is part of the DESC GitHub organization. Other questions can be directed to Chris Walter at Duke University.
Details on the models implemented by imSim including their validations can be found in the imSim Feature Matrix.
Please visit the docs about installation.
Basic usage:
Create a configuration config.yaml, then run
galsim config.yamlFor more details, visit the docs about usage.
imSim is currently still considered beta code. A list of tagged versions and pre-releases of this package can be found here, with the main branch including the most recent (non-tagged) development.
This software was developed within the LSST DESC using LSST DESC resources, and so meets the criteria given in, and is bound by, the LSST DESC Publication Policy for being a “DESC product”. imSim is licensed with a BSD 3-Clause "New" or "Revised" License as detailed in the included LICENSE file.