Astronomical Images Over the Web

[Browsers] [Servers] [Web Serving Test]
There are quite a few servers which offer images of either user-selected or observed sections of the sky (sometimes called "postage stamps"). Current servers and client browsers mostly deal with simple single-wavelength FITS images with World Coordinate System (WCS) sky coordinate to pixel transforms encoded in their headers. See Mark Calabretta and Eric Greisen's paper

Image Servers

Virtual Observatories

Accessing archived data now

International Virtual Observatories

Setting up the protocols to make all online astronomical data accessible

Image Browsers

A Test

If you have the line
image/x-fits                   fit     fits    fts     FIT     FITS
in your mime.types file and a browser set up to deal with the image/x-fits mime type by an entry something like this in a mailcap file
image/x-fits;                saoimage -fits %s
you should be able to retrieve and display a FITS image of M51 like the one at the top of this page from http://tdc-www.harvard.edu/postage_stamp/wpix.fits If you are using SAOimage, click on histeq to histogram-equalize the image and get a good picture of the galaxy M51.

Other settings in your mailcap or helper file to make sure your browser recognizes FITS images should include

image/fits;                saoimage -fits %s
application/fits;          saoimage -fits %s
application/fits-image;    saoimage -fits %s
saoimage may be replaced with your favorite FITS viewer: skycat, saotng, fitsview or xfitsview, ds9, or even xv.

Graphically Editing FITS images

A FITS-reading plug-in for Adobe Photoshop is available, but it can read 8- and 16-bit integer images only.

There is also a plug-in for the GIMP open-source image processing package, and ImageMagick also reads and writes FITS files.

The widely-available PBMPlus and NetPBM graphics toolkits can be used to convert FITS files to other formats or vice versa.

Telescope Data Center

Last updated 13 June 2012 by
Jessica Mink