FITS Tutorial

How do I retrieve FITS Images?

This procedure describes how to download a set of FITS images corresponding to a list of locations that you provide.

SkyServer can be used to execute a more complex query to find the list of fields. Retrieving a very large number of fields is best done using bulk download tools.


Within SkyServer, one can execute a more complex set of queries on fields to get just the ones you want. To start, a simple example query can be generated with the SDSS Imaging Query Server (IQS):

  1. Under Parameters to Return, select “minimal” for the desired set of parameters for your query from the scroll box. This will return a csv with the following parameters
    run
    rerun
    camcol
    field
    obj
     
  2. Under Position Constraints, click on the Proximity Search button.
  3. Cut and paste a CSV file with RA and Dec into the Proximity Search scroll box found under the heading “List of ra, dec, [sep].”
  4. Click on “Submit Request” at the top of the web form to submit your query.
  5. Use the results to input into the SAS service described above, or just use the button at the bottom of the list that will automatically query SAS.

The above methods are useful for retrieving a few hundred fields or so, but if you are retrieving many more than that it quickly becomes cumbersome. In that case, you should instead use the bulk data download tools. The paths to the corrected frames within wget are:

https://data.sdss.org/sas/dr14/eboss/photoObj/frames/[rerun]/[run]/[camcol]/frame-[band]-[run6]-[camcol]-[field].fits.bz2

As described in the bulk data download documentation, there is a similar path usable with rsync. In either case, if you generate a list of run, camcol, field values from a query, you can generate the list of frame files to download.