Finding Deepsearch Images

Finding the Image Names

There are two basic ways to do this. The easiest is to just refer to the web pages which list all images associated with each supernova. Of course, these pages are no longer maintained and are hopelessly out of date, and don't even appear for more recent supernovae, so they are rapidly fading into history.

The more flexible is to run "tracker" (originally by Kim, A. and Kim, M., recently rewritten by Knop, R.) from within IDL. Use the command

dlib,'tracker'

from within IDL to get more information on how this program works. You can also just type 'tracker' in IDL and follow the prompts, though it may seem a touch cryptic. There are shortcuts you can use from the command line to quickly get a listing of certain specifications. Here are a few quick cookbook sample tracker commands which should get you started:

tracker,/nogrids,auto=['n','9765'],/detail: Lists the RA and DEC of sn9765 (perhaps not to be trusted in too much detail), along with all of the images that contain this RA and DEC. Exposure time, filter, seeing, and image quality are listed along with the images.
tracker,auto=[0,8.358,4.352],/yescan,/yesgrid: Lists images, grids (field names), and candidates near the position RA=8.358 hours and DEC=4.352 degrees, in something closely approximating 1950 coordinates. If, say, you wanted to find all images of a certain Landolt field, you could use a command like this. Add a ",/detail" to see which filters and what exposure times were used for each image; you will tend to want short (<20sec) exposures if you are interested in actual standard stars.
tracker,auto=['g','BFC005_2'],startdate='04/03/97',enddate='08/03/97',ftype=5,minimum=100: Lists all R-band (that's "ftype 5") images taken between March 4, and March 8, 1997, which overlap field BFC005_2 by at least 100 square arcminutes.

Once you have the list of image names you are interested in, there is actually some information just in the name of the image.

Actually Finding the Images

Once you've got the image names, you might want to do something with the images per se. The recommended way to do this is from within IDL, because it is set up to deal nicely with it. You don't have to worry what disk the image is on, you can just read it right in with the IDL command:

r=freadimage2(ims1,im1,'mar697btc652csg.fts')

(Where, of course, you substitute the name of the image you want.) At that point, the actual image array is in im1. The structure ims1 has information about the image; type "help,/str,ims1" to view it. You can look at the image itself with the command "frame,im1". For more information about the basic operations, see the chapter on Reading and Displaying Images

By convention, most of our images in the database have north down and east to the left.

If for whatever perverse reason you want to read the image outside of IDL, you may need to know on which disk it is located. You can find this in IDL with the command:

print,findimage('mar697btc652csg.fts')

rknop@panisse.lbl.gov

Last modified: 2000-October-3