Astronomical observations #10 : Hercules Globular Cluster (M13)

astromaniac (59)in #steemstem • 6 years ago (edited)

Hello! Another deep-sky object, which is worth seeing is M13, a globular cluster in the constellation of Hercules. It is the brightest object of this type seen from the northern hemisphere. This cluster under the dark, rural sky is visible to the naked eye.

Wide field image of Messier 13

By Niedźwiadek78 at Polish Wikipedia link [CC BY-SA 3.0 license]

This is undoubtedly one of the most interesting objects that we can see from Poland. A globular cluster, or a sphere built of thousands of stars. M13 lies a little over 2 degrees south of the Herculis eta star. During a good, cheerful night, you can see it with the naked eye as a faint, not sharp star. Cluster's brightness is +6 mag, which, given its small size in the sky (17 arc minutes), makes it quite bright. The binoculars show us the cluster as a small, misty ball. In small telescopes it resembles the nucleus of a comet. Larger ones with a diameter of 6"(150 mm) begin to separate the cluster into single stars. However, the beauty of M13 is revealed only by large instruments with a diameter of over 12"(300 mm), breaking the cluster into thousands of sparkling stars. We can use both small and large magnifications to observe globular clusters. In small 30 - 50X we see a very bright, small ball of stars. However, in typical planetary magnification (150 - 200X), we can break up even single cluster nuclei into single stars. Such objects can be seen in telescopes almost as in the pictures.

Image of M13 from 10" Ritchey-Chretien telescope

By Vanderbei at English Wikipedia link [CC BY-SA 2.5 license]

M13 is a cluster with a diameter of about 145 light years and is located 25.1 thousand light years from Earth. It is the largest and brightest globular cluster in the northern hemisphere of the sky. It contains several hundred thousand stars, perhaps even about a million. I highly recommend you to see this object on some astronomical rally. I hope these tips will help you. Thank you for reading and I invite you to the next part Astronomical observations soon.