Globular clusters in Hercules: M13 (Robotic, NM)
This is Messier 13 - a globular cluster of stars in the constellation of Hercules and probably the best globular cluster in the Northern hemisphere. Its often just known as the "Hercules Cluster"
A small galaxy is seen underneath at about 7 o'clock - IC 4617 and a larger spiral galaxy is seen at the lower left edge - NGC 6207.
M13 is a very, very old collection of stars held together by its own gravity that orbits our Milky Way. This was probably a dwarf galaxy core that lost its periphery to our Milky Way galaxy in the distant past.
Many descriptions on the net state that the brightest star in the cluster is a large variable red star, V11, but it took me quite a while to find an image showing exactly which star that is - Ive marked it in the negative inset.
You are looking at a clump of about 300000 stars in a diameter of 145 light years - imagine what the night sky would look like inside the cluster, given our nearest stellar neighbour is 4.2 LY away.
Most of the stars are extremely old and stable red dwarfs, (about 12 billion years old). Don't expect any young massive stars to go supernovae in this locale.
A few youngish "Blue Stragglers" are seen but essentially these are close binary stars where one partner pulls matter off the other to rejuvenate its nuclear processes and appears to be a young massive blue star.
38 x 6 min exposures from T3 in New Mexico. Dithered and drizzled. Post-processed in PixInsight.
Our galaxy has about 100 globular clusters, the Andromeda galaxy about 370.
You will find more about M13 in some of my previous write-ups in the DSO album here - in particular the "propeller" seen towards the top left and how M13 was accurately drawn and described by astronomers working with "the Leviathan" telescope in Birr Castle, Ireland.
Globular clusters in Hercules: M13 (Robotic, NM)
This is Messier 13 - a globular cluster of stars in the constellation of Hercules and probably the best globular cluster in the Northern hemisphere. Its often just known as the "Hercules Cluster"
A small galaxy is seen underneath at about 7 o'clock - IC 4617 and a larger spiral galaxy is seen at the lower left edge - NGC 6207.
M13 is a very, very old collection of stars held together by its own gravity that orbits our Milky Way. This was probably a dwarf galaxy core that lost its periphery to our Milky Way galaxy in the distant past.
Many descriptions on the net state that the brightest star in the cluster is a large variable red star, V11, but it took me quite a while to find an image showing exactly which star that is - Ive marked it in the negative inset.
You are looking at a clump of about 300000 stars in a diameter of 145 light years - imagine what the night sky would look like inside the cluster, given our nearest stellar neighbour is 4.2 LY away.
Most of the stars are extremely old and stable red dwarfs, (about 12 billion years old). Don't expect any young massive stars to go supernovae in this locale.
A few youngish "Blue Stragglers" are seen but essentially these are close binary stars where one partner pulls matter off the other to rejuvenate its nuclear processes and appears to be a young massive blue star.
38 x 6 min exposures from T3 in New Mexico. Dithered and drizzled. Post-processed in PixInsight.
Our galaxy has about 100 globular clusters, the Andromeda galaxy about 370.
You will find more about M13 in some of my previous write-ups in the DSO album here - in particular the "propeller" seen towards the top left and how M13 was accurately drawn and described by astronomers working with "the Leviathan" telescope in Birr Castle, Ireland.