Sky Object of the Month – July 2017

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Sky Object of the Month – July 2017

(Courtesy LVAS Observer’s Challenge*)

M14 (NGC 6402) – Globular Cluster in Ophiuchus (Mag. 7.6; Size 11’)

             Ophiuchus is home to seven Messier globulars. One of them, M14, is this month’s LVAS Observer’s Challenge. It was discovered by Charles Messier on June 1, 1764 and first resolved into individual stars by William Herschel 19 years later. At magnitude 7.6, it’s relatively faint, but still bright enough to be viewed binoculars and small-aperture scopes.

            I first saw M14 in the summer of 1977 with a 3-inch f/10 reflector and magnifying power of 30X. More recently, I picked it up with a 4.5-inch reflector at 76X. In neither case was there any hint of resolution.

            Finding M14 is somewhat of a challenge, as it lies in a rather star-poor region of Ophiuchus. The accompanying finder chart shows its location about 5 degrees north of the magnitude 4.6 star mu (m) Ophiuchi.

            What is the smallest scope that can resolve this cluster? Is it uniformly bright or condensed towards the center? What is its overall shape – round or oval? Find out for yourself and forward your impressions (image, sketch, and/or notes) to the LVAS via the email addresses listed below.

            M14 lies some 30,000 light years away. It contains an estimated 150,000 stars and spans a distance of about 100 light years.    Glenn Chaple for the LVAS

 

 

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IAU and Sky & Telescope

 

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Mario Motta, MD

 

 

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