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M8 (NGC 6523), Lagoon Nebula - Emission Nebula (HII region) with open star cluster (NGC 6530 / 6533), type "e", in Sagittarius

LRGB combination (Click for a larger view 1800 x 1800 px)

Mouse over to see identifications of objects (see info below)

Hourglass Nebula (200% crop)

Details

M8 (NGC 6523), Lagoon Nebula - Emission Nebula (HII region) with open star cluster (NGC 6530 / 6533), type "e", in Sagittarius

Discovered by Giovanni Battista Hodierna before 1654 and recovered by Guillaume Le Gentil in 1747. It was independently noted as a "nebula" by John Flamsteed about 1680.

M8 - The Lagoon Nebula (NGC 6523) is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and as an H II region and it is one of the finest and brightest star-forming regions in the sky. It is a giant cloud of interstellar matter which is currently undergoing vivid star formation, and has already formed a considerable cluster of young stars. The Lagoon Nebula is estimated to be between 4000-6000 light years from Earth. It spans 110×50 light years. One of the remarkable features of the Lagoon Nebula is the presence of dark nebulae known as Bok globules which are collapsing protostellar clouds with diameters of about 10000 AU. Some of the more conspicuous globules have been cataloged in E.E. Barnard's catalog of dark nebulae: the comet-shaped globule extended North-to-South is Barnard 88 (B 88), small B 89 in the region of cluster NGC 6530, and long, narrow black B 296 at the south edge of the nebula (see rollovr image). In 2006, the first evidence of star formation within the Hourglass was detected when Herbig-Haro (HH) objects were observed. HH objects are small patches of nebulosity that are associated with newly formed stars. They are formed when the gas ejected by these young stars collides with nearby clouds of gas and dust at several hundred kilometers per second.Within the brightest part of the Lagoon Nebula, a remarkable feature can be seen. According to its shape is called the "Hourglass Nebula". This feature was discovered by John Herschel and occurs in a region where a star formation process appears to take place currently. Tthe bright emission is caused by heavy excitation of very hot, young stars, the illuminator of the hourglass is the hot star Herschel 36 (mag 9.5, spectral class O7). M8 also encompasses several other NGC and IC objects: NGC 6523, NGC 6526, NGC 6530, IC 1271, and IC 4678.

North is up. The Horizontal FOV is about 40'. The image almost centered at:

Right Ascension 18 : 04 (h:m)
Declination -24 : 23 (deg:m)
Distance 5.2 (kly)
Brightness 6 (mag)
Apparent Dimension

90' x 40' (arc min)

Seeing: Pickering 7 rating - Good
Optic(s): RC 12" with Astro-Physics corrector @ f/5
Mount: ASA DDM85 Premium
Camera: ATIK 4000 - monochrome CCD – 2048 x 2048 px ; 16x16 mm; 7.4 µm x 7.4 µm
Filters: Astronomik LRGB set, SupaSlim TrueTechnology Computerized Filter Wheel
Dates/Times: 2012-08-20
Location: Rozhen Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exposure Details:

L=36 min, R = 36 min, G = 36 min, B = 36 min (Bin 1), subs. 3 min, Total Exposure Time - 144 min

More details: Dark and flat frames reduction
Guiding: All subexposures are unguided
Processing:

PixInsight / PS

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All Contents copyright Velimir Popov unless otherwise noted.