"M15
in Pegasus" 11/11/99 Kitt Peak, Arizona
(Image by Adam Block, Willis Greiner and Cheryl
Price. Copyright NOAO, all rights reserved.)
This CCD image was obtained using a 16" Meade Schmidt-Cassegrain
telescope operating at f/6.3. The camera used was a SBIG ST-8;
sky chart software was Software Bisque's The Sky, acquisition
and image manipulation software was Cyanogen's Maxim DL. Two
60-second exposures were taken and combined to form a raw
composite image. Dark and flat-field exposures were taken
and applied to the raw images.
M15 is
a beautiful globular star cluster located in the constellation
of Pegasus. It is one of the richer and more compact clusters
of this type. Globulars reside at the edges of galaxies, and,
as such, have become excellent monitors for mapping the size
and shape of our own galaxy, the Milky Way. These clusters
possess a type of variable star that allows astronomers to
measure their distance from us accurately. By combining the
data from all local globular clusters, scientists can essentially
draw a map of our galaxy. By using this method it has been
determined that the Milky Way is a spiral galaxy, and that
we are somewhat out on one of its massive spiral arms. We
have recently observed and measured globular clusters residing
in other galaxies; these measurements are used to help determine
the vast distances to them.
Click
the image to view a larger version.
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