The Little Helix – NGC 6781 Planetary Nebula in NB/LRGB (Aquila)
Planewave CDK12.5; AP 1100GTO AE
ASI6200MM, - Antlia Pro RGB & 3.5nm NB filters
Ha/O: (40,43 x 420s exposures, Bin 1x1, Gain 200)
R,G,B: (31,25 ,28 x 150s, Bin 1x1, Gain 100)
Total Integration Time = 13.2 hours – August 2023
NGC 6781is a barrel shaped planetary nebula and our perspective is straight down the middle of the barrel at the proginator white dwarf star that continues to light it up. The white dwarf and the nebula itself are the remains of a star with a mass roughly 2.5 times the sun. While NGC 6781 is a smaller target and not imaged as often as NGC7293 (The Helix Nebula), it appears somewhat similar in structure, and hence the name of this image (catalogue numbers are so impersonal.) Despite its smaller size, 6781’s brightness reveals some inner complexity within the barrel shape – including “cometary” knots of nebulosity.
NGC 6781 lies 1500 ly from us and is roughly 0.9 ly in diameter, while The Helix Nebula proper is 2.5 ly across and only 650 ly distant.