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The Pleiades (M45) | by Davide Simonetti
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The Pleiades (M45)

The Pleiades (also known as the Seven Sisters and Messier 45). This is one of my favourite autumn targets and one I feel compelled to image every year in order to try and improve on previous attempts. Their rising heralds the arrival of the constellation of Orion which pursues them. I love the mythology associated with the Pleiades and Orion and different cultures have their own stories to explain them. M45 always seems like it should be a fairly easy object to image and it is, however processing it is another matter. This image was made over two nights (24/09/18 and 03/10/18). The original idea was to capture all the data in one night but the first night, although being very clear, was a full Moon and many of the subs were washed out making processing a nightmare. The second night the Moon wasn't an issue but conditions were still less than ideal and we were shooting into a murky sky with high cloud. Ultimately I combined the best shots from both nights and this is the no means perfect but as good as I can get it, not too noisy and a reasonable amount of nebulosity coming through.


The Pleiades are an open star cluster containing middle-aged, hot B-type stars located in the constellation of Taurus. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky.


The cluster is dominated by hot blue and luminous stars that have formed within the last 100 million years. A faint reflection nebulosity around the brightest stars was thought at first to be left over from the formation of the cluster (hence the alternative name Maia Nebula after the star Maia), but is now likely an unrelated foreground dust cloud in the interstellar medium, through which the stars are currently passing.


Computer simulations have shown that the Pleiades were probably formed from a compact configuration that resembled the Orion Nebula. Astronomers estimate that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighborhood.


Information courtesy of Wikipedia:


060 x 300 second exposures at Unity Gain (139) cooled to -20°C

030 x dark frames

063 x flat frames

100 x bias/offset frames

Binning 1x1


Total integration time = 5 hours


Captured with APT

Guided with PHD2

Polar Alignment with SharpCap Pro

Processed in Nebulosity, Fitsworks, Microsoft ICE and Photoshop



Telescope: Sky-Watcher Explorer-150PDS

Mount: Skywatcher EQ5

Guide Scope: Orion 50mm Mini

Guiding Camera: ZWO ASI120MC

Imaging Camera: ZWO ASI1600MC Pro

Baader Mark-III MPCC Coma Corrector

Light pollution filter

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Taken on October 3, 2018