The Legacy Survey of Space and Time (LSST) is anticipated to encompass around 2 million observations spanning a decade, averaging 800 visits per night. The rubin_sim package was built to help understand the predicted performance of the LSST.

The Phot Utils module provides synthetic photometry using provided throughput curves based on current predicted performance.

The skybrightness module incorporates the ESO sky model, modified to match measured sky conditions at the LSST site, including an addition of a model for twilight skybrightness. This is used to generate the pre-calculated skybrightness data used in `rubin_scheduler<>`_.

The Moving Objects module provides a way to create synthetic observations of moving objects, based on how they would appear in pointing databases (“opsims”) created by rubin_scheduler.

One of the major goals for rubin_sim is to enable efficient and scientifically varied evaluation of the LSST survey strategy and progress, by providing a framework to enable these metrics to run in a standardized way on opsim outputs. The Metrics Analysis Framework module provides these tools.