Messier 20
Object Information:

Messier 20, NGC 6514 - TheTrifid Nebula

Constellation - Sagittarius
Size - 30 light years across,
Distance - 6,700 light years [Kepple & Sanner, Night Sky Observers Guide],

This combination emission and reflection nebula is a showpiece of the summer Milky Way. M20 can be easily spotted as a patch of nebulosity and stars with binoculars. The dust lanes which inspired its name are visible with medium size amateur telescopes of 8 to 10 inch aperture.

M20, also known as the Trifid Nebula, was first observed by Le Gentil in 1747 and was subsequently "rediscovered" by Messier in June 1764. Burnhams Celestial Handbook reports that John Herschel was probably the first to call M20 the Trifid Nebula and described it as "consisting of 3 bright and irregularly formed nebulous masses..."

When photographed, M20 is seen to be made up of two separate components, the lower half which contains the conspicuous dust lanes is an emission nebula which glows with the characteristic pink of H II emissions. The less conspicuous blue colored reflection nebula is interstellar dust which reflects light from the bright stars.

Image date:

May 10, 2005

Exposure Information:

This is a LRGB image with exposure times of 24 minutes for each of the color channels. A synthetic luminance was created from the color channels.

Imaged at:

Organ Pipe Cactus National Monument, Arizona


Optics - Takahashi Epsilon 160 f/3.3 astrograph
Mount - Astro-Physics AP 1200 GTO
Camera - SBIG ST-2000XM