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Triffid Nebula

...or an attempt at it, anyway. I have other data so I'll try and reprocess this later in the week.


Object Details:


Discovered by Charles Messier in 1764.


The Trifid Nebula Messier 20 (M20, NGC 6514) in Sagittarius is a remarkable and beautiful object as it consists of both a conspicuous emission nebula and a remarkable reflection nebula component.


Charles Messier discovered this object on June 5, 1764, and described it as a cluster of stars of 8th to 9th magnitude, enveloped in nebulosity, where the remark on nebulosity follows only after the description of nearby M21, and includes that object.


The Trifid Nebula M20 is famous for its three-lobed appearance. This may have caused William Herschel, who normally carefully avoided to number Messier's objects in his catalog, to assign four different numbers to parts of this nebula: H IV.41 (cataloged May 26, 1786) and H V.10, H V.11, H V.12 (dated July 12, 1784). That he numbered this object at all may have its reason in the fact that Messier merely described it as 'Cluster of Stars.' The name 'Trifid' was first used by John Herschel to describe this nebula; this astronomer assigned only one catalog entry to the whole object (h 1991, h 3718, GC 4355) which became J.L.E. Dreyer's NGC 6514.


The dark nebula, which is the reason for the Trifid's appearance, was cataloged by Barnard as Barnard 85 (B 85).


The red emission nebula with its young star cluster near its center is surrounded by a blue reflection nebula which is particularly conspicuous to the northern end. The nebula's distance is rather uncertain, with values between 2,200 light years (Mallas/Kreimer; Glyn Jones has 2,300) and about 7,600 light years (C.R. O'Dell 1963). The Sky Catalog 2000 gives 5,200 light years, a value which is also used by Archinal and Hynes (2003), and which we adopt here. The WEBDA database has 3140, the Hubble Press Release of Jeff Hester (STScI-PRC99-42) gives "about 9000" light years.



Image Details:


Imaging Scope: Astrotelescopes 80mm ED Refractor

Imaging Camera: Nikon D7000

Guiding Scope: William Optics 66mm Petzval Refractor

Guiding Camera: Meade DSI-C

Mount: Celestron CGEM

Exposures: 6 * 7 minute light frames

ISO 800

Aligned and Stacked in Deep Sky Stacker

Post-Processing in GIMP (contrast, saturation, curves and unsharp mask)

Noise Reduction in NeatImage (Filter and Sharpen)

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Uploaded on July 3, 2011