Globular Cluster in Ophiuchus

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M10: A globular cluster is a group of ancient stars (M10 is thought to be a bit over 11 billion years old, young for a globular cluster), gravitationally bound to each other, orbiting the core of its associated galaxy. It takes M10 about 140 million years to complete one orbit around our galaxy's center.

M10 is about 14,000 light years from Earth, and is about two-thirds the angular size of the full moon when viewed from very dark skies (although its outer portions are very dim); it is roughly 83 light years across. It shines at magnitude 6.4 (which might be visible to the naked eye in absolutely dark skies). It has a mass equal to about 200,000 times that of our sun, and contains as many as 100,000 stars (for comparison, there are estimated to be about 1,000 stars within 15 parsecs/49 light years of earth, which is a bubble about that same size). It has an unusual concentration of blue-straggler stars (stars that are much less old than the other stars in the cluster, probably formed from collisions or other interactions between stars in the cluster) near its core.


Technical Information:

LRGB: 85:125:125:112; luminance layer consists of 17 five-minute images; RG channels consist of the combination five-minute images, while B was a group of seven-minute images.

Equipment: RC Optical Systems 14.5 inch Ritchey-Chretien carbon fiber truss telescope, with ion-milled optics and RCOS field flattener, at about f/9, and an SBIG STX-16803 with internal filter wheel (SBIG filter set), guided by an SBIG AO-X, all riding on a Bisque Paramount ME German Equatorial Mount.

Image Acquisition/Camera Control: Maxim DL, controlled with ACP Expert/Scheduler, working in concert with TheSky X.

Processing: All images calibrated (darks, bias and sky flats), aligned, and combined in Pixinsight. Color combine in Pixinsight. Some finish work (background neutralization, color calibration, gradient removal, deconvolution, lessening the dynamic range) done in Pixinsight; some finish work (Neat Image noise reduction and Gaussian blur of RGB layer) was done in Photoshop CC.

Location: Data acquired remotely from Deep Sky West Remote Observatory, Rowe, New Mexico, USA.

Date: Images taken on many nights in August and September 2019. Image posted September 20, 2019.

Date: Image scale of full-resolution image: 0.56 arcseconds per pixel.

CCD Chip temperature: -25C

Copyright 2019 Mark de Regt

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