|HST Primer for Cycle 25|
As described in Section 7.3, the HLA produces source lists for tens of thousands of HST images. The Hubble Source Catalog (HSC) combines these single, visit-based WFC3, ACS, and WFPC2 source lists into a single Master Catalog, hence providing entry into the field of database astronomy. Searches that would require months or years to perform in the past can in many cases be done in seconds with the HSC. This resource may be used to support a wide range of new archival proposals, a few potential examples of which are listed below.Version 2 of the Hubble Source Catalog was released in the fall of 2016. The primary improvements from version 1 were the addition of four years of ACS data and the cross matching of the HSC with spectral observations from COS, FOS and GHRS. A journal-level publication describing the HSC, quality of the data, and potential for doing science is available at Whitmore et al. (2016). A FAQ describing most aspects of the HSC is available. The matching algorithms used by the HSC are described in Budavari & Lubow, 2012.The HSC can be accessed in a variety of ways. For most cases, the best method will be the MAST Discovery Portal (DP). This Virtual Observatory (VO)-based tool provides easy yet powerful access for searches involving 50,000 or less. It provides footprints, object selection filtering, and interactive displays. For larger queries, a powerful CASJobs (CAS = Catalog Archive Server) capability is available1. This resource is based on the Sloan Digital Sky Survey (SDSS) tool2, providing similar support into the world of database astronomy.Below is a list of some of the types of projects that might make particularly good use of this new resource.
• A third method of access is via the HSC homepage. This provides the most flexibility for very detailed queries.A word of caution is in order, however. Unlike SDSS, with a uniform set of filters and all-sky coverage over a substantial part of the sphere, the Hubble database consists of tiny pieces of sky using three different cameras and hundreds of filters. Potential users should pay special attention to the Five Things You Should Know About the HSC webpage. Detailed use cases are available to guide users in common ways to make use of the HSC and to avoid common pitfalls.