Tutorial: Retrieving FITS Images of Objects

1. Prepare a three-column comma-separated value (CSV) list of your objects. The first two columns should contain the ra and dec coordinates of your objects.  The last column should be set to 1 (which is a separation parameter in arcsec).

   ra,dec,sep
   4.2142,-1.2248,1
   227.6103,61.1158,1
   205.9245,67.0318,1
   199.3531,0.0437,1
    

2. Access the Imaging Query Server interface.
    
3. Under Parameters to Return, select the desired parameters for your query from the scroll box.  For example:
   • to get images, select the following parameters:  run, rerun, camcol, field, rowc, colc.  These define an image and object position in the frame.
   • if you select "minimal", the following parameters are returned: 
     • run
     • rerun
     • camcol
     • field
     • colc_u
     • colc_g
     • colc_r
     • rowc_u
     • rowr_g
     • rowr_r
     • psfmag_u
     • psfmag_g   (psf magnitudes of your objects)
     • psfmag_r
     where colc and rowc define your object positions in the ugr filter images. 
   You should be aware that one FITS image is 2048x1361 pixels, where 1 pixel = 0.4 arcsec.  You should also be able to use ds9 or other display software to see your FITS file.
    
4. Under "Filter names to return (for use by the DAS)", select which filter you want your image to be in.
    
5. Under Parameters to Return, select either "Target Imaging", "Best Imaging", or both.
    
6. Under Position Constraints, click on the Proximity Search button.
    
7. Cut and paste the CSV file into the Proximity Search scroll box found under the heading "List of ra, dec, [sep]."
    
8. Click on "Submit Request" at the top of the web form to submit your query.
    
9. A new www page will be opened for you.
    
10. Save the resulting CSV file. Currently (check the .CSV file to make sure), the needed ",filter" keyword is not added to the .CSV file header, even though the requested filter is included on each data line. If this is still true, edit your .CSV file and add "filter" (without the quotes) to the end of the header line and proceed.
     
11. Access the DAS Retrieval Form.
     
    • Under Step 1 on the DAS form, click the fpC box under Data Products in order to retrieve corrected frames containing images of the objects in your list. 
       
    • Under Step 3, upload the edited CSV file.
       
    • Under Step 4, select your desired output file type.
       
    • Under Step 5, click on "Submit Query" to submit your query to the file server.
       
12. Follow the instruction on the www page you'll receive, to download your requested files.