TrevorW
08-07-2010, 09:41 PM
Target: M20, The Triffid nebula
Camera: QHY8 OSC CCD with WO F2 Reducer
Scope: GSO CF RC200
EFR: f/6.4
Mount: EQ6 Pro
Exposure Setting: Prime focus, gain 3 offset 119
Exposures: 11 @ 360s, 5 @ 600s lights taken between 8.35pm and 11:35pm total 1hr 56m 07/07/2010
Seeing: No moon, cool night, usual suburban LP
Guiding: Orion Starshoot Autoguider using PHD with ED80
Focus: Bahitnov mask
Stacking: DSS 3darks 5 flats 5bias frames
Processing: PS CS3 curves, levels, colour, noise etc
Note:
Right Ascension 18 : 02.6 (h:m)
Declination -23 : 02 (deg:m)
Distance 5.2 (kly)
Visual Brightness 9.0 (mag)
Apparent Dimension 28.0 (arc min)
Discovered by Charles Messier in 1764.
The Trifid Nebula Messier 20 (M20, NGC 6514) in Sagittarius is a remarkable and beautiful object as it consists of both a conspicuous emission nebula and a remarkable reflection nebula component.
The dark nebula, which is the reason for the Trifid's appearance, was cataloged by Barnard as Barnard 85 (B 85).
The red emission nebula with its young star cluster near its center is surrounded by a blue reflection nebula which is particularly conspicuous to the northern end. As often for nebulae, magnitude estimates spread widely: Kenneth Glyn Jones gives 9.0, while Machholz has estimated 6.8 mag. This may partly come from the fact that the exciting star, HD 196692 or HN 40 or ADS 10991, is a triple system of 7th integrated magnitude (with components A: 7.6, B: 10.7, C: 8.7 mag). All are extremely hot; component A is of spectral type O5 to O7. The Sky Catalogue 2000.0 even lists 4 more, faint components of this "multiple star:" D: 10.7, E: 12.6, F: 14.0, and G: 13.4 mag. This star is located on the west side of the Trifid Nebula cluster. Situated on the northern edge is HD 164514 of visual magnitude 7.42, a supergiant of spectral type A5 Ia. The presence of these considerably bright stars makes brightness estimates for the nebula difficult.
Camera: QHY8 OSC CCD with WO F2 Reducer
Scope: GSO CF RC200
EFR: f/6.4
Mount: EQ6 Pro
Exposure Setting: Prime focus, gain 3 offset 119
Exposures: 11 @ 360s, 5 @ 600s lights taken between 8.35pm and 11:35pm total 1hr 56m 07/07/2010
Seeing: No moon, cool night, usual suburban LP
Guiding: Orion Starshoot Autoguider using PHD with ED80
Focus: Bahitnov mask
Stacking: DSS 3darks 5 flats 5bias frames
Processing: PS CS3 curves, levels, colour, noise etc
Note:
Right Ascension 18 : 02.6 (h:m)
Declination -23 : 02 (deg:m)
Distance 5.2 (kly)
Visual Brightness 9.0 (mag)
Apparent Dimension 28.0 (arc min)
Discovered by Charles Messier in 1764.
The Trifid Nebula Messier 20 (M20, NGC 6514) in Sagittarius is a remarkable and beautiful object as it consists of both a conspicuous emission nebula and a remarkable reflection nebula component.
The dark nebula, which is the reason for the Trifid's appearance, was cataloged by Barnard as Barnard 85 (B 85).
The red emission nebula with its young star cluster near its center is surrounded by a blue reflection nebula which is particularly conspicuous to the northern end. As often for nebulae, magnitude estimates spread widely: Kenneth Glyn Jones gives 9.0, while Machholz has estimated 6.8 mag. This may partly come from the fact that the exciting star, HD 196692 or HN 40 or ADS 10991, is a triple system of 7th integrated magnitude (with components A: 7.6, B: 10.7, C: 8.7 mag). All are extremely hot; component A is of spectral type O5 to O7. The Sky Catalogue 2000.0 even lists 4 more, faint components of this "multiple star:" D: 10.7, E: 12.6, F: 14.0, and G: 13.4 mag. This star is located on the west side of the Trifid Nebula cluster. Situated on the northern edge is HD 164514 of visual magnitude 7.42, a supergiant of spectral type A5 Ia. The presence of these considerably bright stars makes brightness estimates for the nebula difficult.