The Difference Engine

The good folks over at the High Performance Wireless Research and Education Network do some cool stuff with the images that come out of the Hale Telescope's webcam. They grab and archive an image every three minutes and produce time-lapse animations from them. An interesting twist on the Hale Telescope webcam is the differential image that is produced by subtracting the newest image from the previous one. Sometimes the results are pretty cool looking.

Here's a webcam shot taken in morning twilight from Monday. The differenced image is below. From that you can tell the the telescope is slowly tracking across the sky & that the mirror cover closed.