Noob

[Hoopa]

Hi all,

I've been looking around the site here for a while, and I must say that it's very interesting, and I have always found the heavens to be of great interest. I'm in crispy Canberra, and I've been thinking about putting a telescope together, and was hoping to get some advice from some wiser heads.

At the moment I know only a little about telescopes. As well as the telescope as a whole, I'm also interested in the process of constructing a telescope, thus my first question. For a noob, am I biting off too much first up by trying to build the whole scope (bought mirrors)? From what I've been looking at, I was considering probably a 10" dob. The whole construction doesn't seen too complex but I don't know if there are any obvious pitfalls to look out for.

Again, with not much telescope experience, what sort of expectations should I have of this sort of scope?

I'm sure that I can probably think of plenty of other questions, but they can wait for another post at the moment.

Cheers
Hoopa

[rmcpb (Rob)]

Welcome to IIS Hoopa

A 10" dob would be a great start into the world of astronomy. It would blow your eyes out on the moon and the planets and is great at the deep sky stuff as well. I use an 8" which is brilliant but you will see a lot more in a 10".

[astro_nutt]

Hi Hoopa!!!..and a big welcome to IIS!!!..
Your best bet is to have a good close look at a 10 inch Dob..it might look simple enough..but it takes a lot of engineering to make it work!!..
Try looking up a few classifieds from a local astronomy group or from a reputable telescope dealer!!
Spend a bit of time with a good planisphere, star atlas..plus visit the local library and have a browse through the Astronomy section!!!..
Cheers!

[Hoopa]

Thanks all for the comments.

I guess 'simple' was a relative term. It would be no fun if it were too easy. I find the "putting it together" bit half the fun (or at least some of it), I just didn't want to get into a project that was as complex as building the space shuttle. I think it will also give me a better understanding of the beast if I actually get my hands dirty making it.

The view is about what I had been guessing at, but it's always good to ask. I've been doing plenty of reading to date, but am all too aware of how much I still don't know yet. I have found a few links on IIS to planispheres and star atlases, so I will have to look into that further.

Does anyone know where I can find the local telescope dealers in a place like Canberra? Strangely they're not as common as the corner shops.

Speaking of getting hand's dirty, I have a question of mirror focal lengths. Why is it that an f/4 mirror is 'better' than an f/5 mirror? I understand that an f/4 will have a shorter focal length, but how does relate to a 'better' view, or is this just a subjective thing based on the kind of objects that you want to look at (i.e. planets vs. DSOs)?

Cheers
Hoopa

[iceman (Mike)]

Hi Hoopa! Welcome to IIS!

I don't know of any telescope dealers in Canberra - I doubt there's any specialised ones (or we'll have heard of them). The best bet might be a camera dealer or something? But don't be put off shopping from Bintel, Andrews, MyAstroShop etc. Plenty of people order over the phone through these guys and have not been disappointed.

Where did you hear f/4 was better than f/5? No one focal ratio is "better" than another. There are pros and cons to each.

f/4 will give you a wider field of view (shorter focal length), but will be much less forgiving on collimation and eyepiece design. Collimation will be CRITICAL in a fast scope and your average widefield eyepieces will look horrible in half of the FOV. The tube will be shorter (shorter focal length) meaning (perhaps) a more comfortable eyepiece height.

f/6 is easier on collimation, easier on eyepiece design but the tube will be longer and for a larger mirror you may need a small step ladder (unless it's an 8" f/6 like the GSO's).

f/5 is somewhere in-between. Most of the commercial scopes of 10 and 12" aperture are f/5. Collimation is critical as with every newtonian, and widefield eyepieces are usable but the view around the edges is still not great unless it's an expensive model like the Pentax or Nagler.

Planets or DSO's make no difference. It doesn't matter what the focal length is for planets, you'll still put in a high power eyepiece to get the magnification you want.

[Hoopa]

yeah, I'd pretty much gathered that such outlets would be fairly specialised, thank god the net.

not sure where I picked up one was better than the other, maybe it was just someone talking about not having to lug the larger scope around , but thanks for the clariffication. f/5 is what I had seen on most store bought scopes, so I guessed that was probably about the middle ground.

[Ric]

Hi Hoopa and welcome to IIS, hope you have a great time here.
The Canberra Astronomical Society have telescopes for hire to it's members.
I've added a link to their website, hope it helps.

http://www.mso.anu.edu.au/cas/

As you say there are no speciality Astro shops in Canberra, I usually go through the Sydney dealers which are a nice bunch of people, always willing to help.

Cheers

[KG8]

Originally Posted by Hoopa

At the moment I know only a little about telescopes. As well as the telescope as a whole, I'm also interested in the process of constructing a telescope, thus my first question. For a noob, am I biting off too much first up by trying to build the whole scope (bought mirrors)? From what I've been looking at, I was considering probably a 10" dob.

Hi Hoopa!

I'm just returning to the interest after a long many years, and after looking around the net for a few weeks I had a pretty good idea on what I needed to get back into astronomy. But then I had a stroke of luck! I contacted one of the local astronomical societies and went up to their monthly astro camp. There I saw all the equipment in action, saw all the developments in technology that had come since I had left. There was even a guy there who had built his own 16" Dob, and a beautiful one it was. It had a computerized position readout, collapsible tubular supports for the upper section and a nifty slide up dew shield curtain to protect the mirror. I was very impressed. Now like I said, I already had it all sorted out in my head what I wanted you buy before I went, but after going to that weekender, I came away with a completely different outlook and am very grateful.

[leon]

Welcome Hoopa, you will have a blast here.

Leon

[Hoopa]

Thanks for that guys.
I intend to get to one of the upcoming events at CAS to check it all out. I also have some ideas, but the going to the local organisations sounds like a good idea.

Cheers
Hoopa