M20, a nebula in Sagittarius, is known as the Trifid Nebula. Its nebulosity is a combination of both emission and reflection nebulae and also includes a star cluster.
M21, an additional star cluster, appears on the far right.
Taken in suburbia, my light pollution filter seems to enable good contrast and detail for black & white imaging; but in colour (see below) the image appears with a strong blue hue which I have found difficult to reduce without affecting the object itself.
Exposure: 10 x 4 min ISO 800
Gear: Skywatcher ED120 refractor, 840mm f/l, f/7, Canon EOS 60D. LP filter, no flattener
Location: Leumeah, NSW
Messier 20, NGC 6514
Visual magnitude: +6.3
Apparent diameter: 29 x 27 arc-min
Actual diameter: 44 light years
Distance: 5,200 light years
Messier 21, NGC 6531
Visual magnitude: +5.9
Apparent diameter: 14 arc-min
Actual diameter: 16 light years
Distance: 1,200 light years
The processed colour image is not very satisfying:
Images © R.Powell