2022 April 30 ~ M3, globular star cluster in the constellation Canes Venatici (The Hunting Dogs)

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Photographed at Algonquin Provincial Park, Ontario, Canada, between 02.03 and 02.19 EDT

(285 km by road north of Toronto)

* Altitude of M3 at time of exposures: 63°

 

* Total exposure time: 8 minutes

* 1253 mm focal length telescope

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Description:

 

This globular cluster was the first object in the catalogue of deep-sky objects that famed French observer and comet hunter Charles Messier discovered himself, on May 3, 1764. It is just below naked eye visibility, with a magnitude of 6.4, and is a lovely sight in moderate amateur telescopes.

 

From Wikipedia:

 

This cluster is one of the largest and brightest, and is made up of around 500,000 stars. It is estimated to be 11.4 billion years old. It is ... 32,600 light-years away from Earth. Messier 3 is quite isolated as it is 31,600 light years above the galactic plane and roughly 38,800 light years from the centre of the Milky Way. It contains 274 known variable stars, by far the most found in any globular cluster.

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Technical information:

 

Nikon D810a camera body on Explore Scientific 152 mm (6") apochromatic refracting telescope, mounted on Astrophysics 1100GTO equatorial mount

 

Eight stacked frames - each frame:

1253 mm focal length

ISO 1000; 1 minute exposure at f/8; unguided

 

(with LENR - long exposure noise reduction)

 

Subframes registered in RegiStar;

Stacked and processed in Photoshop CS6 (levels, brightness/contrast, colour balance)

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Done