Globular clusters (GCs) are compact, gravitationally bound systems of up to 1 million stars. They are associated with galaxies of all types and masses and can be used to trace dark matter in galaxies among other topics. The  Large Synoptic Survey Telescope (LSST) will be one of the main photometric studies for the 2020s-2030. LSST will study the entire southern sky reaching unprecedented photometric depths. However, the LSST  photometric software "LSST stack" is currently not optimized to perform photometry of point sources (such as GCs) projected against a variable background.

This presents a great challenge for the study of GC systems. We propose to use publicly available data from the Japanese Subaru Hyper Suprime-Cam (HSC) telescope to prepare for LSST. HSC provides publicly available data, in a small area, with characteristics similar to those expected from LSST. The performance of the “LSST stack” will be tested on the HSC data, which in turn will lead to publishable results. The findings will then be reported to the LSST data management team to optimize strategies for the science of GCs and compact stellar systems in general.