First light with 130PDS - I've been wanting to get this scope for two years now, I finally got it!

No Coma Corrector was used. I calculated that with the sensor size of the 290, the coma at f/5 with this scope would be smaller than the airy disk and would not need a coma corrector.

I conducted a quick little star test on M92 from my horrendously light-polluted backyard and it turns out that that is the case, there no visible coma with this sensor size - just some zero chromatic aberration, pure mirror imaging - like I first did with my SW 150PL at f/8 (see previous images, i.e. Albireo, Ring Nebula). I have a bit of a fetish for using reflectors without glass correctors in the light path, which would essentially turn the scope into a catadioptric system..

Was also very pleasantly surprised to see no need for refocusing between the Astronomik RGB filters. They are truly parfocal when used in a reflective system. I'm so used to having to refocus each one with refractors.

However, the AZ-GTi struggled somewhat with tracking, surprise surprise, it's rated at 11lbs and I pushed it to 16lbs, so that's the case here. I originally shot 360 RGB exposures and blinked out 164 due to tracking errors. Need to get another AVX for this scope.

Looking forward to more clear skies (horrendous weather conditions for Astronomy in New York lately) so I can travel to a (slightly) darker site and shoot some more of the cosmos with this scope.

Hope you like it and all the best

Target Description:

"Messier 92 (NGC 6341) is a globular cluster in the constellation Hercules. It is one of the brighter globular clusters in the northern hemisphere, but it is often overlooked by amateur astronomers because of its proximity to the even more spectacular Messier 13.

M 92 was discovered by Johann Elert Bode in 1777. Charles Messier independently rediscovered it and cataloged it in 1781, along with eight other objects (M84-M91) which are all Virgo Cluster galaxies. William Herschel first resolved it into stars in 1783.

Observing Messier 92

Located on the north edge of Hercules, this impressive globular cluster deserves more attention than it gets, but is outclassed by the Great Hercules cluster, M 13, to its southwest. M 92 is harder to locate than its more famous cousin, but is still a splendid object, visible to the naked eye under very good conditions, and a showpiece for optics of every size. At visual magnitude 6.3, it is only slightly fainter than M 13, and about 1/3 smaller, with an angular diameter of 14'.

Interesting trivia on M 92: the North Celestial Pole occasionally passes within 1° of this cluster, due to the precession of Earth's axis. M 92 becomes the "North Cluster" in about 14,000 years (16,000 AD), as it was about 12,000 years ago (10,000 BC).

Physical Properties

M 92 is about 26,000 light years distant, only little farther away than its brighter apparent neighbor M 13; and it is intrinsically smaller and fainter. Its true diameter is about 100 light years; its absolute magnitude is -8.1, a luminosity of 150,000 Suns (60% that of M 13), and it may contain a mass of up to 330,000 Suns. M 92 is approaching us at 112 km/sec.

The stars of M 92 are exceptionally poor in iron and other elements heavier than hydrogen. This suggests that M 92 was formed before the gas and dust of our galaxy were enriched with heavy elements, and therefore that M 92 is exceptionally old, even for a globular cluster. M 92 may be a bit younger than M 13, or about 12 billion years old.

Only 16 variable stars have been discovered in this globular, 14 of which are of the RR Lyrae type. One is of the W Ursae Majoris type, and one of the very few eclipsing binaries found in a globular cluster. In these dense stellar agglomerates, close encounters occur frequently, so that binary systems will be disturbed, and eventually destroyed."

Source: SS6 Pro