This Automator workflow downloads the latest image from the Astronomy
Picture of the Day site (http://antwrp.gsfc.nasa.gov/apod/astropix.html)
and sets it as your desktop background. It saves old copies of the
images in a folder within ~/Pictures to be used as screen saver
images. The last step in the workflow is to open the APOD page in
Safari so you can read the description of the picture.
The inspiration for this script came from an article by Andy Ihnatko
1. Unpack the ZIP file.
2. Copy AstronomyPictureOfTheDay to your Applications folder.
3. Run the application.
To have a new picture downloaded every day, use iCal to schedule an
event to run daily to open the application.
You will want to periodically clean out the screensaver pictures
folder to remove old pictures.
For the latest version, check
Fixes a problem with APOD pages that include links to multiple images
so that only the main image is downloaded.