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This is one of the many different images of M8 that there will be in this site. M8 is one of the best known and imaged nebulae in the sky. Also known as NGC 6523, it is a large hydrogen and dust cloud, hot enough to be emitting in its characteristic 656.3nm. The earliest observation of this nebula are from 1654 by Hodierna. Flamsteed around 1680 and Chéseaux in 1746 both observed and catalogued the nebula before Messier did it in 1764. In fact Messier did not only include the nebula in his description of M8, but also the open cluster NGC 6530 that formed in it. The nebula is primarily illuminated by the 6th magnitude star 9 Sgr, a very hot O5 star.This star is the one located just above-right the apparent center of the nebula.
The conspicuous spikes above and below the brightest stars are due to the fact that the camera used is Non-antiblooming (NABG). This is an excellent camera, highly sensitive, allowing shorter exposures, but on the other side, when imaging areas with bright stars, this problem appears.
Additional Information
Object
Name(s): M8, NGC 6523, Lagoon Nebula
Type: Emission Nebula
RA: 18h 03m 47s
Dec: -24º 22’ 54.3”
Constellation: Sagittarius
Size (arcmin): 90×40
Magnitude: +6
Distance: 4,500
Image
Date: 2014-05-23
Location: SSO near Coonabarabran, NSW Australia
Size (arcmin): 34×25
Telescope: Planewave CDK 20” f/4.5
Camera: FLI ML6303E (3072x2048pix)
Guiding: Yes, but not recorded
Total exposure: 84 min (L: 21min; RGB: 63 min)
Processing: CCDStack, Photoshop CC 2016 and PixInsight