Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 September 1 
Posted on 08/31/2003 10:18:26 PM PDT by petuniasevan
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 September 1
Explanation: The beautiful Trifid Nebula (aka M20), a photogenic study in cosmic contrasts, lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. A star forming region in the plane of our galaxy, the Trifid alone illustrates three basic types of astronomical nebulae; red emission nebulae dominated by light from hydrogen atoms, blue reflection nebulae produced by dust reflecting starlight, and dark absorption nebulae where dense dust clouds appear in silhouette. The bright emission nebula on the right, separated into three parts by obscuring dust lanes, lends the nebula its popular name. Many details are apparent in this gorgeous high-resolution image of the Trifid. For example, light-year long pillars and jets sculpted by newborn stars - visible here in the upper right-hand corner of the emission nebula - appear in Hubble Space Telescope close-up images of the region.
Trifid Nebula (M20)
| Right Ascension | 18 : 02.6 (h:m) |
|---|---|
| Declination | -23 : 02 (deg:m) |
| Distance | 5.2 (kly) |
| Visual Brightness | 9.0 (mag) |
| Apparent Dimension | 28.0 (arc min) |
Lagoon Nebula (M8)
| Right Ascension | 18 : 03.8 (h:m) |
|---|---|
| Declination | -24 : 23 (deg:m) |
| Distance | 5.2 (kly) |
| Visual Brightness | 6.0 (mag) |
| Apparent Dimension | 90x40 (arc min) |
If you are not TOO far north (sorry RightWhale), you can observe these nebulae in summer. Binoculars will show them both unless your haze/light pollution is severe.
The following image is from the Digital Sky Survey. It includes the Trifid at the top and the Lagoon at the bottom.
Here is a deeper exposure in color, courtesy of the AAT:
Finder chart for the many interesting objects in Sagittarius:
Look, they came from outer space and ate people and there's always trouble with triffids, or something like that, and..........
you said "Trifid"? Nevermind :)
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