2022 Oct. 1 ~ Open Star Clusters in the constellation Cassiopeia

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Photographed at Algonquin Provincial Park, Ontario, Canada

(285 km by road north of Toronto)

between 00.14 and 00.34 EDT

* Altitude of centre of frame at time of exposures: ~68°

* Temperature 2° C.

 

* Total exposure time: 10 minutes

* 660 mm focal length telescope

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Description:

 

Eight open star clusters are shown in this image of a star-rich region of the constellation Cassiopeia.

 

Our Milky Way galaxy contains some 1,100 open clusters of stars, which are loosely bound together gravitationally. Because of this loose nature, these cluster drift apart over time until they are unrecognizable as star clusters . Most of them are therefore only a few dozens of millions of years old.

 

An exception is the faint reddish cluster IC 166 in the extreme upper left of this image. It is estimated to be about a billion years old, and is still recognizable as a cluster because it is located outside any of the heavily populated arms of the milky Way. Thus the gravitational effect of other stars is minimal, and the cluster has survived for a long time.

 

For a version of this photo WITH LABELS and more information about the clusters in this image, click on your screen to the RIGHT of the photo, or click here:

www.flickr.com/photos/97587627@N06/52399315319

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Technical information:

 

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

 

Ten stacked subframes; each frame:

ISO 5000; 1 minute exposure at f/8

(with LENR - long exposure noise reduction)

 

Subframes stacked in RegiStar;

Processed in Photoshop CS6 (levels, colour saturation)

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Done