Galaxy Zoo Starburst Talk

Obtaining SDSS DR10 data using CasJobs

  • JeanTate by JeanTate

    As Karen Masters explains in the GZ blogpost Using Galaxy Zoo Classifications – a Casjobs Example, CasJobs is a SQL-based tool for extracting data from SDSS. DR10 is accessible from the SDSS-III CasJobs site.

    The general context - accessing SDSS DR10 data - is explained well on this SDSS site: Data Access for SDSS DR10. In particular, the section "Catalog Data":

    Catalog data summarize quantities measured from the images and spectra such as magnitudes, redshifts, and object classifications. These are available either from the Catalog Archive Server (CAS) database, or as binary tables in FITS file format.

    Here it makes clear that CasJobs is what to use if "I need to ..." "generate my own database with custom tables of a subset of SDSS data"

    From reading the CasJobs Guide, it seems fairly straight-forward (if a little time-consuming) to extract anything that's in any SDSS DR10 catalog, for the 6,004 Quench project objects, or any subset of them (such as just the Quench Control objects).

    How? Here's my high-level description of the steps (NOTE: I haven't actually done any of these yet!):

    1. Obtain a list of the SDSS IDs for each of the 6,004 objects, e.g. from Tools
    2. Import these into CasJobs MyDB
    3. Write CasJobs queries for the data you want, using as Context MyDB
    4. Run the queries, download the results from MyDB

    Comments? Suggestions?

    Posted