Globular Cluster M15 (NGC 7078), class IV, in Pegasus

RA 21h 30m 05.5s DEC +12 10 39; Approximate distance: 33 thousand(!) light years.
Visual Brightness 6.2 (mag); Apparent Dimension 18.0 (arc min)

Globular cluster M15 is among the more conspicuous of these great stellar swarms.
At a distance of about 33,600 light years, its diameter of 18.0 arc min corresponds to a linear extension of about 175 light years, and its total visual brightness of 6.2 magnitudes corresponds to an absolute magnitude of -9.17, or roughly 360,000 times that of our sun.

Source and more: SEDS


October 14, 2009 18:23 - 19:28 UT
Imaging: William Optics Zenithstar 80 ED II APO, f/6.8 [focal length 545 mm], Astronomik Lum filter; ATK16IC b/w camera, K3CCDTools.
Exposures: L: 22x90s [1x1], RG: 10x60s [1x1]; B: 10x40s [1x1]; unguided.

October 13, 2009 18:29 - 19:26 UT
Imaging: William Optics Zenithstar 80 ED II APO, f/6.8 [focal length 545 mm], Astronomik Lum filter; ATK16IC b/w camera, K3CCDTools.
Exposures: Lum 21x90s, unguided. RGB was not captured because of clouds.

August 28, 2006 20:14 - 20:19 UT.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm] and Baader Infra Red Blocking Filter.
Camera: Vesta Pro SC3a b/w RAW webcam, 14 autoguided exposures of 10 seconds.

October 12, 2005 20:02 - 20:30 UT.
Imaging: TAL-2M 15cm f/8 in prime focus with with Vesta SC3a colour webcam, Baader Infra Red Blocking filter; 25 autoguided exposures of 30 seconds.

September 8, 2004 22:21 - 22:33 UT.
Imaged with TAL-2M 6 inch f/8 Newtonian in prime focus; Baader Infra Red Blocking filter.

September 7, 2004 22:56 - 23:03 UT .
Imaged with TAL-2M 6 inch f/8 Newtonian in prime focus; Baader Infra Red Blocking filter.
Note: this image is based on only 3 frames, as I had huge technical problems with my focuser.
By the time I had fixed the focuser M15 had almost moved behind the trees ...

October 17, 2003 20:08 - 20:23 UT.
Exposure: 14 x 30 seconds, unguided.
YRGB post processing.

September 1, 2003 22:09 - 22:58 UT.
TAL-2M 6 inch f/8 Newtonian with focal reducer @ f/4.6; Baader Infra Red Blocking filter; unguided.
Exposure: 23 x 30 seconds.
YRGB post processing.