2019 Aug. 2 ~ The open star cluster M39 in the constellation Cygnus

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Photographed at Algonquin Provincial Park, Ontario, Canada

(285 km by road north of Toronto)

between 22.30 and 22.40 EDT

* Altitude of the cluster at time of exposures: 54°

* Temperature 17° C.

 

* Total exposure time: 4 minutes

* 660 mm focal length telescope

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Description:

 

M39 is a very loose and large cluster of quite bright stars that we see against the backdrop of the bright band of the Milky Way as it crosses the northern hemisphere summer sky. It is located about 1,000 light years from our solar system.

 

M39 was discovered by Guillaume Le Gentil in 1749, and Charles Messier added it to his catalogue of deep-sky objects in 1764.

 

Open star clusters are young groupings of stars, generally no more than a few million years of age. The individual stars are loosely bound together gravitationally, and gradually move apart over time, making them unrecognizable as a cluster.s

 

For a version of this photo WITH LABELS, click on your screen to the RIGHT of the photo, or click here:

www.flickr.com/photos/97587627@N06/48494904262

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Technical information:

 

Nikon D810a camera body on Tele Vue 127is (127 mm - 5" - diameter) apochromatic astrograph, mounted on Astrophysics 1100GTO equatorial mount

 

Eight stacked subframes; each frame:

ISO 3200; 30 seconds exposure at f/5.2, unguided

(with LENR - long exposure noise reduction)

 

Subframes stacked in RegiStar;

Processed in Photoshop CS6 (brightness, contrast, colour balance)

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Done