M20 and M21 (George Simon)

Celestial hemisphere: Southern · Constellation: Sagittarius (Sgr) · Contains: M 20 · M 21 · NGC 6514 · NGC 6531 · Trifid Nebula

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M20 and M21

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M20 and M21

The Trifid Nebula was, if memory serves, the second DSO I ever imaged. That was more than a decade ago, using a first-generation Meade DSI-C. My equipment has improved vastly since then, as have my acquisition and processing skills, but I have never returned to the Trifid to re-image it. I think I have avoided it simply because it so frequently imaged. However, I finally decided that it was time to give it another go. Because it is so frequently imaged, I wanted to find a way to give it a somewhat out-of-the-ordinary treatment. Thus, I settled on a framing that would include the nearby open cluster M21.

Both M20 and M21 are about 5,000 light years distant. Despite their proximity to each other, however, they are unrelated to each other. M20 is startlingly young, only about 300,000 years old. M21, on the other hand, is about, 4.6 million years old, quite young for an open cluster, but still much older than its celestial neighbor.

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	Image of the day	Top pick	Top pick nominations	Total submitted
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The “AstroBin Image of the Day and Top Picks”, or IOTD/TP, is a long-running system to promote beautiful, interesting, peculiar, or otherwise amazing astrophotographs, with a focus on technical excellence. Learn more.

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M20 and M21

M20 and M21

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M20 and M21

M20 and M21

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