Next entry: Some great doubles revisited

Previous entry: Argo Navis digital setting circles

Two "stick men" and some other beautiful deepsky objects

On August the 21st I observed some deepsky objects with the 15x80 Vixen and the Sky Window. The objects I observed where Mu Cephei, M 52, NGC 7789, NGC 457, Stock 2 and The double cluster in Perseus.

Mu Cephei
I started with Mu Cephei, Herschel’s Garnet Star. After searching for half an hour I finally found it, using a printed star chart from TheSky. As you can see on the image below, Mu Cephei lies

in an arc of 6 stars. Once you know to locate this group, it is very easy to identify the Garnet star.

image
Mu Cephei in an arc of stars. Map generated with SkyTools2 by Capellasoft

This is the very first time I see the Garnet Star through my big binoculars and it looks really impressive, with its bright deep orange glow.

M 52
Next on the list was M 52. To find M 52, I started at Alpha Cassiopeiae. From there I went in a straight line to Beta Cassiopeiae, and extended the line with the same distance Alpha-Beta. With direct vision there is not much to see, just a hint of a small patch of light. With averted vision, M 52 turns into a hazy path of light, with a triangular form, very easy to see with the 15 x 80. There are 1 or two stars visible. The rest of the cluster just looks like a small nebula.

NGC 7789
M 52 has a magnitude of 6.9 and its diameter is 12’ Another bright cluster in Cassiopeia, NGC 7789 has a magnitude 6.7 but it’s diameter is a bit arbitrary when you read different publications and sources about this beautiful cluster. Most publications state that its diameter is 16’. If you compare both magnitudes and sizes of these two clusters, they should look almost the same through the 15x80 big binoculars, but they don’t! NGC 7789 looks not only a bit brighter, but much larger than M 52. After looking through some recently bought books, I noticed that according to Archinal and Hynes (Starclusters) and Crossen and Rhemann (Sky Vistas) the diameter of NGC 7789 is 25’. I think this is much closer to what you really see, than the 16’ I find in most sources on the Internet. I go for 25’.

You can find NG 7789 by starting at Beta Cassiopeiae. From there you move your binoculars into south-south-western direction for about 3.5 degrees where you will spot the bright cluster immediately. Through the 15x80 I could not resolve NGC 7789. It remained a bright hazy patch of light, though sometimes you (think?) you see a hint of granulation. NGC 7789 is made up of hundreds of stars, but no stars shines brighter than mag 10.7. Under light polluted skies my 15 x 80 never showed any stars dimmer than mag. 9.5 to 10. Anyway, it’s one of my favourites!

NGC 457 (Caldwell 13)
An even more impressive cluster for big binoculars is NGC 457. This cluster lies 2 degrees to the south-southeast of Delta Cassiopeiae. The cluster looks like a “stick man” (or as ET according to other observers). When you look at NGC 457 through the 15 x 80’s, you immediately see the two “bright eyes”, as well as the main “bar” of a body, the arms and feet. The cluster’s diameter is about 20’ (Archinal and Hynes). It’s visual magnitude about 6.4, a great sight through both binoculars as well as through a telescope.

Stock 2
From NGC 457 it’s only a short “trip” to Stock 2, a big open cluster, 1 degree in diameter, that lies between Epsilon Cassiopeiae and the famous Double Cluster in Perseus. Stock 2 looks even more like a “stick man” than NGC 457. The body, arms and legs are very easy to see. In the 15 x 80 you can even see some kind of oval head. You can see about 50 to 70 stars in big binoculars. Stock 2, NGC 457 and NGC 7789 are definitely my favourite clusters in Cassiopeia!

The Double Cluster in Perseus (Caldwell 14)
From Stock 2 it’s again a short hop to the famous Double Cluster in Perseus, NGC 884 and NGC 869. There are no words to describe the beauty of these two clusters through big binoculars or a rich field telescope. This is the first, or one of the first objects I saw through a telescope, almost 30 years ago, and it still is one of my favourites, which I visit on every possible occasion. Both clusters are about 30’ in diameter (as large as a full Moon), and they are separated only by 0.5 degrees. Both clusters are already well resolved, and to me they look like two boxes of jewels in the night sky. As I said earlier, I cannot find the words to describe the beauty of these two great open clusters, so go out and take a look for yourself. It will become one of your favourites too!

With the Double Cluster I ended my observing session for tonight. I used the 15 x 80 and the Sky Window for all my observing tonight. I located the objects with the help of the SkyAtlas 2000 and a printed map of the Mu Cephei area. 

Posted by Math on 10/04 at 09:59 AM
Deepsky log • (0) TrackbacksPermalink