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| M69, A Globular Cluster, - this image cropped and reduced from the original photo, Click on photo above for a full frame full rez image. |
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M69, similar to its neighbor
M70, is one of the
smaller and fainter globular clusters in Messier's catalog. From mid
northern latitudes it can just be seen on clear dark nights with 10x50
binoculars. It can be found low in the summer Milky Way to the right side of
the bottom stars of the Teapot. M69 is about 7 arc minutes in diameter in
this photo, corresponding to roughly 61 light years at its 29,700 light
years distance. Very deep photos show that it is somewhat more extended: 9.8
arc minutes, or linearly, about 85 light years. The visually bright compact
core is about 3 arc minutes in diameter. As M69 is quite close to the
Galactic Center (only about 6,200 light-years distant), its tidal
gravitational radius is comparatively small, about 72 light years. Its stellar
concentration is about average for a globular cluster, with a central core
diameter of roughly 6 light years, with a half-mass radius of about 7.2 light years.
M69 has stars that are a little more metal rich than many globulars, meaning that its stars show a relatively high abundance of elements heavier than Helium. This indicates that it is a little younger, or formed more recently than many globulars. Nevertheless its stars have significantly less metals than stars like our Sun, indicating that even this globular was formed at early cosmic times when the universe contained less heavy elements. |
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10"
F6.3 Schmidt Cassegrain Telescope, (1600mm F.L.) Modified Canon
300D camera with IR-UV filter, placed at the scopes prime focus |