M53: A globular cluster in Coma Berenices

Images taken: April 16, 2005, by Laura Doty.

Telescope: Meade 12 in with f/5.6 focal reducer (f=67in), guided with AO7 adaptive optics on a 9.2 mg star. Size of the image: 9'x13'; South is up, East is left.

Camera: SBIG ST-7 CCD

Seeing: 3 as.

Exposures: 15 min red, 15 min green, 2x15 min blue (1 hour total).

---

M15 is an old globular cluster, a collection of a hundred thousand low-metallicity stars, 70,000 light years away. Its stars are barely resolved in a telescope.

Image processing: CCDoops + CCDsoft + Photoshop CS.