Re: M53, a glob I seldom see

From: Jane E. Smith (jesmith@No-Spam)
Date: Mon Apr 21 2003 - 08:43:00 MST

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    Incredibly nice images Richard. NGC4490 is sure interesting. And thanks
    for the glob lesson. I had always wondered why M13 looked like a pile of
    little blue marbles. Now I know.

    Jane of the Valley

    At 02:35 AM 4/21/2003 -0400, you wrote:
    >Friday night I did a bit of imaging from my backyard in Castro Valley.
    Among the targets that night were NGC4490 and M53.
    >
    >I don't think I have seen M53 too many times. One thing I noticed was a
    large number of blue stars in it.
    >
    >I had recently read in the book "The Big Bang" by Joseph Silk of Oxford
    that Globs contain a lot of old blue stars. Old blue stars: I always had
    thought blue stars were young hot stars.
    >
    >Well as it turns out, when a star depletes its hydrogen fuel, it can
    resort to fusing Helium and if it does, the stars get a lot hotter and look
    blue.
    >
    >Instead of the Blue Straggler theory I had heard before, it appears that
    the blue stars are just helium burning stars. That makes sense when you
    consider that Globular Clusters are some of the oldest objects in the
    universe. It did not make sense to me that ancient globs would have young
    hot blue stars in them.
    >
    >Here is a link to my M53 image:
    >
    >http://www.rdcrisp.darkhorizons.org/m53_globular_cluster_page.htm
    >
    >and NGC4490:
    >
    >http://www.rdcrisp.darkhorizons.org/ngc4490_rgb_page.htm
    >
    >Both of these were taken with my newly refurbished C14. I had been
    fighting mirror flop with it for some time and finally applied a lot of
    grease to the central focus tube and that seemed to greatly improve the
    situation. It is not 100% gone, but it is usable now where it was really
    not before.
    >rdc
    >
    >
    >



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