2018-09-07 Omega/Swan/Horseshoe nebula (M17)

Yet another summer DSO catched in my early september sessions.

I find this looks like more a horseshoe than a swan; I have read the swan could be seen with a different orientation, and less exposure (such as Herschel's drawings).

Interesting facts: The nebula is estimated about 15 ly diameter at a distance of 5-6000 ly (~1/20 milky way diameter), and weights 800 solar masses; Its cluster hosts 800 stars, is forming another thousand in the outer regions, and would be aged "just" 1 million years.

Gear: Olympus E-PL6 with Skywatcher 130PDS 632mm/4.86 and SWCC at f/4.55 on Omegon EQ-300 tracking RA
Capture: 24 lights × 40s × 3200 ISO, master dark
Site: deep country 26km from Limoges, France
Sky: good (given bortle class 3, usual sqm >21), subject high enough for no LP
Processing: Regim 3.4, Fotoxx 12.01+