Instrument

12.5" RCOS @  ~f/9 (2880 mm fl) 0.64 arcsec / pixel.  The Zoomify image scale is 0.85 to 2.55 arcsec / pixel.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ internal filter wheel, AstroDon Filters

Acquisition Data

5/9/2010 to 5/13/2010 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.  AOL guided

Exposure

Lum (no filter) 100 min (20 x 5 min, bin 1x1)

RGB               180 min (12 x 5 min each, bin 2x2)

Software

• CCDSoft, CCDStack, Photoshop CS w/ the Fits Liberator plugin, Noel Carboni's actions and Russell Croman's GradientXTerminator.

• eXcalibrator for (u-g), (g-r) color calibration, using 5 stars from the SDSS-7 database.

• PixFix32 (pre-beta) to repair hot/cold pixels and column defects.

• CCDStack to calibrate, register, normalize, data reject, combine the sub exposures and LRGB color.

• PhotoShop for LLRGB combine &  on-linear stretching.

North is to the top.
The globular cluster, M5, contains roughly 100,000 stars. These stars formed together and are gravitationally bound. Stars orbit the center of the cluster, and the cluster orbits the center of our Galaxy.

About 160 globular clusters are known to exist in a roughly spherical halo around the galactic center. Globular clusters do not appear spherically distributed as viewed from the Earth, and this fact was a key point in the determining our Sun's location in our Galaxy.

Globular clusters are very old, with M5 being one of the oldest at a computed age of 13 billion years. Its diameter is about 165 light years, making it one of the larger globular clusters. At its distance of 24,500 light years this diameter is about 23 minutes of arc.

Source: NASA APOD & SEDS