M 8 and M 20 – Emission nebulae in the constellation Sagittarius (the Archer)

A mosaic of 6 images of the colorful nebula region around M 8 (Lagoon Nebula) and M 20 (Trifid Nebula). Besides the two large gas nebulae, there are numerous other objects in this celestial region:
Messier 21 is an open star cluster with an apparent diameter of 15 arcminutes at a distance of 3700 light-years. The cluster contains about 60 stars and has an exceptional concentration of blue B-supergiants in the core region. These stars have lifetimes of only 10 to 15 million years, making M 21 a very young cluster. Its age is estimated to 4.5 million years.
The nebular region in the left half of the image is about 800 light-years behind the Lagoon Nebula and consists of several red emission and blue reflection nebulae.
The open cluster NGC 6546 contains about 150 stars at a distance of 3000 light-years.
At the lower edge of the image, the light from the globular cluster NGC 6544, which is about 10,000 light-years away, is attenuated by interstellar dust and it appears distinctly yellowish.

larger image
Date:July 2019 und 2021
Optics: Pentax SDP 105
Aperture:105 mm
Focal Length: 670 mm
Camera: Canon EOS 700Dac
Exposure: 6-frame mosaic, total 72 x 600 s
Location: Chamaeleon Observatory, Onjala Lodge, Namibia
Processing: Deep Sky Stacker, Photoshop
Diameter:90 light years (M 8)
Distance:5,200 light years (M 8)
annotated image

image field in the sky