star clusters

[hullobservertory]

Hay can I add you as a friend ghostdance you are very helpful

[ghostdance]

Er... (blush)...sure!

[hullobservertory]

Will do in a bit so are there any clusters in big dipper

[hullobservertory]

So where are you in the world ghost dancer

[ghostdance]

No, no clusters in the Plough (Big Dipper for our US friends) - not that I'm aware of. There are galaxies tho.

No offence, but it may be better to put all your questions in one large post -  one-liners may work conversationally, but don't encourage comprehensive answers, plus there are other members who can answer with much more experience and knowledge than me! Try writing down all you want to ask about clusters, doubles etc. You also don't want to run foul of the post-farming rule

Look up Ghost Dance - fascinating story...

[des anderson]

Hi,if you want a good book on the subject,try The Webb Society deep sky observer`s hand book vol 3-open and globular clusters,and if you want double stars try vol 1.both a minefield of information,i had mine since the 1980s and still use them for reference.

[BeanerSA]

Another good book (if you can get past the typos) is Star Clusters And How To Observe Them, from Springer.

[hullobservertory]

Cheers guys appreciated spread the word about my forum I find star clusters very interesting

[hullobservertory]

Does anyone no if double stars are clusters

[ronin]

No double stars are simply 2 close by stars, either gravitationally doubles or optical doubles.

Even ones like Polaris that are a multiple star system are not classed as clusters.

Suppose somewhere that there is a definition of how many stars make a cluster, or that rare commodity common sense is applied.

[mikeDnight]

So what equipment does everyone have for viewing clusters I have celestron binoculars 15x70

Like you, I use 15x70 binoculars, but also a 100mm F7.5 refractor giving an almost 4° rich field at my current lowest power.

Mike

[Qualia]

Hull,

You could say that a star cluster per se appears as a concentration of several stars or more as seen against the stellar background. Inevitably, the definition is a little vague but I think it is workable.

From this we can make two divisions: open clusters and globular clusters.

Globular clusters are typically made up of hundreds of thousands of stars all crammed into an area of just a few hundred light years across. In a small telescope, say, something with just 3" of aperture they appear as a soft cloudy globe, or ike a pinch of cottonwool rolled in the palm of your hand. There are over 150 known globular clusters in the Milky Way; living in the halo of our galaxy and orbitiing the galactic centre. It turns out that they are among the oldest objects in the universe, as old as 13 billion years.

Open clusters live in the spiral arms of our galaxy which are the sites of rich star formation and death. As such, open clusters consist of relatively young stars, made up of no more than a few hundred and which are quite spread out and tend to disassociate over time. The youngest open clusters are just several million years old, while the oldest are just a few thousand million years old.

Here is a little map to help frame the idea:

Binary star or Double stars is a bit of a misleading term; misleading for they may contain more than just two stars. A double star is a solar/star system made up of usually two stars orbiting around their centre of mass. Needless to say, 'double' stars may in fact contain more than two stars and indeed, some open clusters and globulars contain binary, triple and quadruple star systems orbiting around their mutual centre of mass. 

Hope this helps a little

Final comment:

By way of passing, SGL tends to work better when we try to collect our thoughts and to the best of our abilities, communicate them in single, paragraphed posts. Obviously, this is not always possible but I feel we ought to works towards this manner of communication, for not only does it make the threads easier to read, but it also promotes more meaningful discussion. However, SGL does have a place for more general chit-chat which can be found in 'The Lounge' (non-astro) at the bottom of the main page.

Needless to say, away from 'The Lounge', an over use of one liners - especially when we address such complex and interesting issues as you have raised in this thread - tend to limit or even dumb down conversation that deserves to be fuller and more fleshed out. There's also the suspicion that an overuse of quick one liners is a form of 'post-farming' that is not permitted on SGL.

My best regards,

Rob

[spike95609]

Living in a light polluted area, I'm very limited in terms of galaxies and nebula that I can see, but star clusters are much easier to pick up, or at least the brighter elements of them. I started off using my 15x70 bins, but since I got the 10" scope I use that all the time. At 15x magnification, the binoculars can find a lot of them but you can't see what's going on in there. Crank it up to 80x with the scope, or 200x if I'm feeling silly, it's a complete new world. So I've made myself a little book with every star cluster in the sky listed, hundreds of them, and I'm going through them constellation by constellation, ticking them off.

[hullobservertory]

I'm haveing issues naming a cluster I have observed it is in cygnus and has been described as looking like a coat hanger any.names or advice where I.Could find out it name would.be great

[Cornelius Varley]

I'm haveing issues naming a cluster I have observed it is in cygnus and has been described as looking like a coat hanger any.names or advice where I.Could find out it name would.be great

If you haven't already done so I suggest that you download Stellarium http://www.stellarium.org/ 

[hullobservertory]

Yeah named it thanks for link

[A-N-Y]

I'm haveing issues naming a cluster I have observed it is in cygnus and has been described as looking like a coat hanger any.names or advice where I.Could find out it name would.be great

Check the following link for the coathanger (Brocchi's cluster). http://en.wikipedia.org/wiki/Brocchi%27s_Cluster

Till this day M11 (Wild Duck cluster) is my favourite, as it is stated "The Wild Duck Cluster is one of the richest and most compact of the known open clusters, containing about 2900 stars." (http://en.wikipedia.org/wiki/Wild_Duck_Cluster)