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 March 22 
Posted on 03/22/2003 5:55:42 AM PST 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 March 22
Explanation: Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. This planetary nebula's simple, graceful appearance is thought to be due to perspective -- our view from planet Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star. Astronomers of the Hubble Heritage Project produced this strikingly sharp image from Hubble Space Telescope observations using natural appearing colors to indicate the temperature of the stellar gas shroud. Hot blue gas near the energizing central star gives way to progressively cooler green and yellow gas at greater distances with the coolest red gas along the outer boundary. Dark, elongated structures can also be seen near the nebula's edge. The Ring Nebula is about one light-year across and 2,000 light-years away in the northern constellation Lyra.
M57 Ring Nebula
| Right Ascension | 18 : 53.6 (h:m) |
|---|---|
| Declination | +33 : 02 (deg:m) |
| Distance | 2.3 (kly) |
| Visual Brightness | 8.8 (mag) |
| Apparent Dimension | 1.4x1.0 (arc min) |
Finder chart for M57
Again, don't expect to see what the Hubble sees. Not only is this from a LARGE aperture space-based 'scope, it is a time exposure. Color is not evident visually (though theoretically under perfect seeing conditions one might detect a greenish tinge). If you had an 8 or 10-inch backyard 'scope and were observing M57 in moderately light-polluted skies without a filter, here's an idea of what you'd see:
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