List Of Dark Nebulae
This is a list of dark nebulae (absorption nebulae), also called "dark clouds". List * Finger of God Globule *E Nebula (Barnard 142 and 143) *Barnard 68, possibly the closest to Earth at about 400 light-years. *Le Gentil 3 *Sandqvist 111 *Sandqvist 112 *Sandqvist 150 *Sandqvist 155 *Sandqvist 157 *Sandqvist 166 *Sandqvist 169 *Sandqvist 171 *Sandqvist 178 *Bernes 157 (Sandqvist and Lindroos, SL 39-41), another close dark nebula of the Corona Australis Molecular Cloud, which includes NGC 6729 *SL 41 *LDN 43 (Cosmic Bat Nebula) *LDN 193 *LDN 206 *LDN 208 *LDN 535 *LDN 615 *LDN 621 *LDN 624 *LDN 673 *LDN 688 and LDN 687 *LDN 695 *LDN 749 *LDN 762 *LDN 763 and LDN 764 *LDN 750 *LDN 771 *LDN 780 *LDN 790 *LDN 792 *LDN 793 *LDN 794 *LDN 795 *LDN 796 *LDN 798 *LDN 866 *LDN 898 *LDN 921 *LDN 923 and LDN 924 *LDN 925 *LDN 930 *LDN 935 *LDN 940 *LDN 950 *LDN 954 *LDN 958 *LDN 972 *LDN 1010 *LDN 1020 *LDN 1066 *LDN 1073 *LDN 1083 *LDN 1105 *LDN 1109 *LDN 1139 *LDN 1141 *LDN 1142 *LDN 115 ...
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Dark Nebula
A dark nebula or absorption nebula is a type of interstellar cloud, particularly molecular clouds, that is so dense that it obscures the visible wavelengths of light from objects behind it, such as background stars and emission or reflection nebulae. The extinction of the light is caused by interstellar dust grains in the coldest, densest parts of molecular clouds. Clusters and large complexes of dark nebulae are associated with Giant Molecular Clouds. Isolated small dark nebulae are called Bok globules. Like other interstellar dust or material, the things it obscures are visible only using radio waves in radio astronomy or infrared in infrared astronomy. Dark clouds appear so because of sub-micrometre-sized dust particles, coated with frozen carbon monoxide and nitrogen, which effectively block the passage of light at visible wavelengths. Also present are molecular hydrogen, atomic helium, C18O (CO with oxygen as the 18O isotope), CS, NH3 (ammonia), H2CO (formaldehyde), c- ...
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Corona Australis Molecular Cloud
Corona Australis is a constellation in the Southern Celestial Hemisphere. Its Latin name means "southern crown", and it is the southern counterpart of Corona Borealis, the northern crown. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. The Ancient Greeks saw Corona Australis as a wreath rather than a crown and associated it with Sagittarius (constellation), Sagittarius or Centaurus. Other cultures have likened the pattern to a turtle, ostrich nest, a tent, or even a hut belonging to a rock hyrax. Although fainter than its northern counterpart, the oval- or horseshoe-shaped pattern of its brighter stars renders it distinctive. Alpha Coronae Australis, Alpha and Beta Coronae Australis are the two brightest stars with an apparent magnitude of around 4.1. Epsilon Coronae Australis is the brightest example of a W Ursae Majoris variable in the southern sky. Lying alongside the Milky Way, Corona Australi ...
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LDN 687
LDN is contractional slang for the city of London in the United Kingdom. LDN may also refer to: Arts and media * London Daily News, former newspaper * BBC London (formerly ''BBC LDN''), broadcasting body * "LDN" (song), a 2006 single by Lily Allen Language * Láadan, a feminist, sci-fi conlang (by ISO 639-3 code) Medicine * Licensed Dietitian Nutritionist, a qualified dietician * Low-dose naltrexone, off-label use for treatment of immune diseases Science and technology * Day-night average sound level, Ldn or DNL * Linked Data Notifications, a communications protocol * Lynds' Catalogue of Dark Nebulae, not to be confused with LBN (Lynds' Catalogue of Bright Nebulae) Transport * Llandanwg railway station Llandanwg railway station is in the village of Llandanwg in Gwynedd, Wales. It is an unstaffed halt on the Cambrian Coast Railway with direct passenger services to Harlech, Porthmadog and Pwllheli to the north and west, and Barmouth, Machynllet ...