Monday, March 5, 2012

Globular Cluster Photo Series (Part 16): NGC 3201

The globular cluster I have for you today is the first one I've imaged not found on Charles Messier's famous list. Instead, it bears the New General Catalogue (NGC) number 3201. The New General Catalogue was [and remains] one of the most comprehensive lists of deep-sky objects visible with typical amateur equipment ever, even though it was originally compiled in the 1880's. It contains a core group of 7,840 objects, and was later revised to include an additional 5,386.

Anyway, NGC 3201 is a lovely cluster far enough south in the constellation Vela the Sail that Messier wouldn't have been able to see it from his location in Paris. It's about 15,000 light-years away and perhaps 80 light-years across, which combines to give it the impressive visual size of 18.6 arcminutes, nearly two-thirds the width of the full Moon and twice as wide as M97 from yesterday.

In the northern hemisphere, most of the brightest objects are in the Messier catalog; thus, almost by definition, anything without a Messier number is not going to be as bright or as impressive as something with one (there are some exceptions both ways, but it's a general rule of thumb). In the southern hemisphere, this is not the case simply because Messier couldn't see down there.

This was well demonstrated the night I got the data for M79 which I showed in the previous post, and NGC 3201, which turned out to be the more impressive one. Here's the picture for comparison:

NGC 3201 in Vela.

M79 turned out to be another fairly small nondescript cluster (although its possible extra-galactic origins make it pretty cool in other ways). NGC 3201 was rather impressive by comparison. I was even able to make it out faintly by eye in one of our 14-inch telescopes, which was neat. Come to think of it, this is probably the southernmost globular cluster I've imaged to date.

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