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I have seen M2, 13, 15, 22 and 56 (faint) with our 8 inch. Frankly, they all look the same to me (although I think M15 is the most impressive). Is there something I am missing? Are there any unusual looking globulars?

I still think they are beautiful and like to reflect that their stars are as old as the Universe.

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Their overall form is somewhat similar, but there are definite differences between one globular and the next. Some are highly concentrated at the center, while others have a more mild and broad central concentration. Some are quite bright and easy, while others are poor and faint, becoming challenge objects in modest sized amateur telescopes. An example of one with a distinct feature is M5. It has a small dense almost star-like core embedded in its brighter central region. That almost nuclear core at really high power (400x and up) is made up of three or four very closely spaced stars in a sort of triangle, but it takes really high power and excellent seeing to resolve it. Another example is M22, which is larger and rich but is somewhat oval in overall shape, and does not have an extremely concentrated core region. M4 has the famous central 'bar' of stars running across its core, while NGC 6712 is the "weird" globular, with an almost triangular shape or a slightly off-center core region when viewed in modest apertures. Each globular has its own charm which is best realized by viewing as many of them as you can (and in as large an aperture as you have access to). Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org

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Another example is M22, which is larger and rich but is somewhat oval in overall shape, and does not have an extremely concentrated core region.

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Of the NGC globs, I'd say ngc 7006 is worth taking a look out.

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If you want one that is *really* way out there, check out G1, a small faint globular that is part of M31's big group of globulars:

G1: R.A. 0h 32m 46.3" Dec. +39 deg. 34' 31" (mag. 13.7).

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You know whats a hell of an open cluster that approaches globular intensity that is triangular instead of circular?

M37 in Auriga.

WOW. My all time fav open cluster in the heavens [that i can see].

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Don't compare it to Pluto. Some convention of globular experts will want to downgrade it to a dwarf globular.

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You know whats a hell of an open cluster that approaches globular intensity that is triangular instead of circular?

M37 in Auriga.

WOW. My all time fav open cluster in the heavens [that i can see].

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I like the sound of M37's location. Also, I don't think I have ever knowingly looked at an object in the galactic disk outside of the Orion Arm. I shall add it to my list.

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Don't compare it to Pluto. Some convention of globular experts will want to downgrade it to a dwarf globular.

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And so they should! We must keep changing our definitions to keep the true globulars within single figures. Also, we must define globular by what it orbits and not by what it is so that any globular slungshot into intergalactic space through galactic interactions immediately changes in nature.

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Globular clusters are generally defined by their overall form (roughly spherical with some central concentration), their numerical populations (from around 100,000 to several million component stars), and their "metalicity" (globular cluster stars tend to have fewer heavier elements than stars in most open clusters and tend to be older). M37 is clearly not a globular cluster, as it is more triangular in shape and has no distinct denser central core of stars. It has only about 150 stars brighter than magnitude 12.5 (at most, its total population is probably less than 500 stars). Its stars are considerably younger than those in most typical globular clusters. It is clearly a Population I object rather than being Population II as most globular clusters are. M37 is a great open star cluster well worth a good long look, but I'm afraid that it isn't even close to what a true globular is like physically. Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org

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I have just had a look at 7006, a pleasant hop in the finder and recognisably a globular. Its long, lonely orbit made me think of it as like a Pluto of globulars.

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If you want one that is *really* way out there, check out G1, a small faint globular that is part of M31's big group of globulars:

G1: R.A. 0h 32m 46.3" Dec. +39 deg. 34' 31" (mag. 13.7).

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Well, M32 looks like a globular to me although my yard isn't dark enough to get the halo.

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M32 has a fairly bright almost star-like core, which differs from the form of some globulars, so don't be afraid to kick up the power a little. Indeed, in a 12 inch scope on a good dark night, there are even a few globular clusters close to M32 (G156 is the brightest one near M32 at magnitude 15.6). Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org

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Although I only use binoculars, I detect differences in my unresolved views of globular clusters.

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You know whats a hell of an open cluster that approaches globular intensity that is triangular instead of circular?

M37 in Auriga.

WOW. My all time fav open cluster in the heavens [that i can see].

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M37 is clearly not a globular cluster, as it is more triangular in shape and has no distinct denser central core of stars. It has only about 150 stars brighter than magnitude 12.5 (at most, its total population is probably less than 500 stars).

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My apologies if it seemed as though i were morphing 37 into a globular. Its intensity however seemed like it might be of interest to someone whom ha seen a few globulars and was looking for something a little different. They are VERY different by definition as you point out, but in terms of visual stellar impressions, M37 is quite the rich treat.
I think its an excellent variation on a visual theme.

Pete

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Although I only use binoculars, I detect differences in my unresolved views of globular clusters.

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Me too. There's lots of differences among globulars visible in giant and supergiant binocs.

To start with, some have higher surface brightness than others. As Hrundi suggests, contrast the dim, hazy Class XII NGC 5466 in Boötes with the more concentrated and brighter M3 4° to its west. Another good surface brightness contrast (though they're a bit far apart) is between the very loose Class XI M55 in Sagittarius and the dense Class I M75 to its east.

David Knisely mentions the stellar core of M15 in Pegasus, which is distinctly star-like even in, say, 15x50 binocs. This is one of the "core-collapse" globulars: clusters in which most of the brightest stars, because they are among the cluster's heaviest, have literally sunk into its center. M30 in Capricornus, M62 in Scorpius, and M70 in Sagittarius are other core-collapse globulars. Though best seen with binocs from the southern hemisphere, all three exhibit their stellar core with giant binocs from dark-sky sites.

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Craig,

Good to see you posting here.

I have enjoyed your book with Gerald Rhemann, "Sky Vistas: Astronomy for Binoculars and Richest-Field Telescopes." Rich with detail and insight. Nifty photos by Rhemann, too. Your Introduction to Keppel and Sanner's Night Sky Observer's Guide is also excellent.

But you have an unfair advantage over most authors: you can write.

Bill

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