Just today the STEREO data for comet Elenin started being officially published and I wanted to show how and where to go to get it for those interested. The images are stored at the Solar Heliospheric Activity Research & Prediction Program section on the United States Naval Research Laboratory servers and the search form can be found here.
As you can see there are a lot of parameters that can be setup to do various kinds of searches, but we are mostly interested in comet Elenin so we can ignore most of the settings.
To set the time you can either download a whole day worth of images and look through them for comet Elenin or you can enter the time when you know the spacecraft took the images. To find the time go here, to find out what the schedule is and any changes that might have occurred. For example, in the minutes posted on August 2nd we see,
* The 135 degree rolls on Behind to observe comet Elenin started yesterday
(Aug 1). The rolls will be between 8-10 UT each day, except for Aug 5 and
Aug 12, when the rolls will be between 10-12 UT.
Ok so lets enter that time, 8 to 10 hours universal time. Notice that the day is set by default to four days in the past, that's because it takes four days for the data to be processed before it appears on the servers for downloading by the public. The first images taken of comet Elenin occurred four days ago so we do not need to set the day at the time of this writing, which is August 5th.
Then it's just a matter of setting the camera to HI-2 and the spacecraft observatory to B for behind and that's it! Clicking search brings up the images we want.
The jpegs are just small images to get an idea of how the larger fits format images will appear. What's needed next is to process the fits images into a format you can use. Fits is an image format that is well known to the scientific community. You'll want to get software that can do the processing and that can be found here. The Fits Liberator also comes in a plugin format for Photoshop if you use one of the newer versions of Photoshop.
That should get you started finding, downloading and processing your own STEREO images nearly directly from the STEREO spacecraft.