{"id":50447,"date":"2023-10-17T13:13:25","date_gmt":"2023-10-17T13:13:25","guid":{"rendered":"http:\/\/78decba9-b006-458d-865a-cc71d948ad2b"},"modified":"2023-10-17T13:32:34","modified_gmt":"2023-10-17T13:32:34","slug":"8-deep-sky-objects-to-observe-in-cassiopeia","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/8-deep-sky-objects-to-observe-in-cassiopeia\/","title":{"rendered":"8 deep-sky objects to observe in Cassiopeia"},"content":{"rendered":"

Locate galaxies, nebulae and star clusters in the famous W-shaped constellation. <\/p>

By Pete Lawrence\n <\/p>

Published: Tuesday, 17 October 2023 at 13:13 PM<\/p>

\n\n

The constellation Cassiopeia contains a wealth of deep-sky objects that can be seen through a telescope.<\/p>

Cassiopeia<\/a> is a great target for observers because it is circumpolar, meaning it can always been seen in the night sky.<\/p>

Its W shape can be seen to do a complete rotation around the North Celestial Pole, approximately marked by Polaris, the North Star.<\/p>

The constellation<\/a> is distinctive and almost as easily recognisable as the constellation Orion<\/a>.<\/p>

It represents the Seated Queen and the name of star Schedar means \u2018breast\u2019, a reference to its position in the heart of the Queen.<\/p>

Cassiopeia is a great target to observe with the naked eye as it’s so prominent, even from a suburban location.<\/p>

But get out your telescope and explore the constellation and you’ll find a wealth of deep-sky objects.<\/p>

8 deep-sky objects in Cassiopeia<\/strong><\/h2>NGC 7789<\/strong><\/h3>Caroline’s Rose by Jaspal Chadha, London, UK<\/figcaption><\/figure>
We start with the well-known cluster NGC 7789, also called the White Rose Cluster or more commonly Caroline\u2019s Rose<\/a>, after discoverer Caroline Herschel.<\/p>
The Rose is one of the best-known deep-sky objects in Cassiopeia.<\/p>
It\u2019s located 2.9\u00b0 southwest of Caph (Beta (\u03b2) Cassiopeiae), one of the points forming a right-angled triangle together with Schedar (Alpha (\u03b1) Cassiopeiae), Caph being at the right angle.<\/p>
It has an integrated magnitude of 6.7 and appears around 20 arcminutes across through a 150mm scope with over 50 members resolved.<\/p>
A 300mm scope resolves around three times as many stars.<\/p>
The \u2018Rose\u2019 gets its name from curving lines of stars which give the impression of petals, clustered around the flower\u2019s centre.<\/p>
M52\/NGC 7635<\/strong><\/h3> $\"M52,$
M52, NGC7653 and NGC7538 by Bill McSorley, Leeds, UK.<\/figcaption><\/figure>
Our next target is 6.5\u00b0 northwest of NGC 7789. Locate mag. 4.9 4 Cassiopeiae and 0.7\u00b0 to the south you\u2019ll find the Salt and Pepper Cluster, M52.<\/p>
Listed at mag. 6.9, a 150mm scope shows a hazy patch with around 30 individual stars scattered over a 10-arcminute region, a number that triples through a 300mm scope.<\/p>
While looking at M52, observe the region 0.5\u00b0 southwest. Here lies NGC 7635, a region of diffuse nebulosity.<\/p>
A 150mm scope may struggle, but a 250mm scope should show it as a glowing patch around 1 arcminute across.<\/p>
This is the Bubble Nebula<\/a>, so-called because of the ring structure visible in long-exposure photographs, representing the edge of a giant bubble blown in the nebula by the star SAO 20575.<\/p>
NGC 7790<\/strong><\/h3> $\"Star$
Credit: Robert Mura \/ Stellarium<\/figcaption><\/figure>
Head 4.5\u00b0 east from M52 and you\u2019ll arrive at another open cluster, NGC 7790. Alternatively, look 2.5\u00b0 northwest of Caph.<\/p>
This cluster is fainter than Caroline\u2019s Rose, with an integrated magnitude of 8.5.<\/p>
It\u2019s considerably smaller too, a 150mm scope revealing a compact object around 4 arcminutes across. <\/p>
Under suburban skies, it appears as a hazy glow, giving the impression of a footprint with three 11th-magnitude stars marking some of the toes and a mag. 10.2 one marking the heel.<\/p>
The northern \u2018toe\u2019 is Cepheid variable CF Cassiopeiae.<\/p>
A 250mm scope resolves around 25 stars in a vaguely rectangular area of 4 x 2 arcminutes.<\/p>
NGC 129<\/strong><\/h3> $\"NGC$
NGC 129. Credit: Bernhard Hubl \/ CCDGuide.com<\/figcaption><\/figure>
To locate NGC 129, imagine the line between Caph and Gamma (\u03b3) Cassiopeiae, the mag. 6.5 cluster being slightly on the Caph side of the mid-point.<\/p>
Through smaller instruments, this is tricky to see as it\u2019s pretty sparse, making it one of the more challenging Cassiopeia deep-sky objects.<\/p>
A pair of red stars (mag. 8.8 HD 236446 and mag. 8.6 HD 236449) slightly further east along the line described point at it, in case you\u2019re having difficulty.<\/p>
Another pointer is HD 2377 at mag. 5.9, located 0.25\u00b0 south of the cluster\u2019s centre.<\/p>
A 300mm scope shows around 50 stars in an area 15 arcminutes across, three 10th-magnitude members forming a distinctive, almost equatorial, triangle in the cluster\u2019s centre.<\/p>
NGC 189<\/strong><\/h3> $\"NGC$
NGC 189. Credit: Donald Pelletier \/ Digitised Sky Survey<\/figcaption><\/figure>
Next up is the tricky cluster NGC 189, which lies 1.5\u00b0 east-northeast of NGC 129. Alternatively, find it 2.1\u00b0 west and a fraction north of Gamma Cassiopeiae.<\/p>
It\u2019s a poorly concentrated object with an integrated magnitude of 8.8.<\/p>
It\u2019s also relatively small, contained in an area 3.7 arcminutes across. To see it properly be prepared to up the magnification.<\/p>
There\u2019s a square asterism<\/a> adjacent to it.<\/p>
With a bit of imagination, a fifth star forms a pattern with the square, not dissimilar to the \u2018house\u2019 asterism that forms most of Cepheus.<\/p>
Smaller instruments show a haze with a few resolved members, while a 250mm scope shows 20 or so stars in the area.<\/p>
NGC 281<\/strong><\/h3> $\"NGC$
NGC 281: The Pacman Nebula by Mike Garbett, Walsall, West Midlands, UK.<\/figcaption><\/figure>
Nebula NGC 281 is 0.5\u00b0 west and 4.1\u00b0 south of Gamma Cassiopeiae or, if you prefer, 1.7\u00b0 east of Schedar.<\/p>
A 150mm scope shows a nebulous glow around 11 arcminutes across.<\/p>
Four brighter stars appear within the nebula boundary, along with a scattering of fainter ones.<\/p>
The middle star is interesting as it splits into several components with powers over 100x.<\/p>
Long-exposure photos reveal a dark lane crossing the nebula which, together with a small dark patch forming an eye, look like a basic sideways face.<\/p>
This gives NGC 281 its informal name, the Pacman Nebula<\/a>.<\/p>
NGC 185<\/strong><\/h3>
$\"NFC$
NFC 185. Credit: Johannes Schedler \/ CCDGuide.com<\/figcaption><\/figure>
Next is a galaxy 12.4\u00b0 east and 5.3\u00b0 north of NGC 7662, within southern Cassiopeia.<\/p>
An easier route is to look 1\u00b0 west of mag. 4.5 Omicron (\u03bf) Cassiopeiae.<\/p>
NGC 185 is a satellite galaxy of M31 and suffers from low surface brightness.<\/p>
Although listed at mag. 9.2, its large apparent size of 11 x 10 arcminutes spreads its light across a large area.<\/p>
Having said this, it does have a well-defined core and through a 150mm scope shows as a 1-arcminute circular glow surrounded by an elongated 4-arcminute halo.<\/p>
Larger apertures reveal distinct granularity in the halo and there appears to be a star-like point at the centre of the core.<\/p>
NGC 147<\/strong><\/h3>
$\"NGC$
NGC 147. Credit: Bernhard Hubl \/ CCDGuide.com<\/figcaption><\/figure>
Located 1.9\u00b0 west of Omicron Cassiopeiae or 0.9\u00b0 west of NGC 185, is NGC 147, a dwarf spheroidal galaxy listed at mag. 9.5.<\/p>
Don\u2019t let that fool you though; this is a challenging target due to its large overall apparent size, similar to NGC 185: 13 x 8 arcminutes.<\/p>
Essentially, NGC 147 is a very-low-surface-brightness glow and one of the trickiest of the galactic Cassiopeia deep-sky objects.<\/p>
It is best suited for larger instruments, but even here you\u2019ll be lucky to see much more than the glow of its core region.<\/p>
A 300mm instrument under dark-sky conditions will show an elliptical haze 3 x 2 arcminutes in size.<\/p>
Like NGC 185, this is also a satellite galaxy of M31, the Andromeda Galaxy.<\/p>
This guide originally appeared in the October and November 2023 issues of BBC Sky at Night Magazine.<\/em><\/strong><\/p> <\/body><\/html>\n
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