beginner trying to choose a telescope

[Tohrazer]

aye, thats what im starting to think, a dob it is, thanks alot guys!

[Tohrazer]

question, why is a 12" truss dob more expensive than a non truss dob?

[Whippy]

I'd hazard a guess that they're more diffcult to manufacture. A solid tube is just a sheet of metal, rolled and sealed while a truss version needs several pieces.

Tony..

[themos]

Straight newtonians do not really produce the big flat field you need for imaging, apart from being very long and heavy which puts a strain on any mount. You could go for a Ritchey Chretien design I suppose but they hardly count as beginner scopes. Apparently there's a Taiwanese GSO 10" RC.

[Tohrazer]

what do you guys think of this? http://telescopesandbinoculars.co.uk/acatalog/info_374.html

[themos]

You might mot get any responses, very few people at SGL have the cheaper Meades.

[Tohrazer]

righto.. thinking a 12" skywatcher dobsonian now, im pretty much sure about it. going to set us back around £550 - would you tend to agree thats a decent investment or?

[themos]

Well, it's what I have, I got mine second hand for about £350, so you're looking at dropping £200 of value for the time you're going to use it. I love it but I've only had it a year and I have never had an SCT or a refractor to compare against. MartinB loves his, too.

[Tohrazer]

awesome, thanks! dont suppose you could describe what views of different things look like? globulars, nebulae, open clusters? do the young open clusters look blue and beautiful?

also which should i go with, the meade lightbridge truss, or the skywatcher tube? this bit i could really use an opinion or two on

[Doc]

I have the lightbridge truss dob and I love it.

Being a truss dob it needs frequent collimation. Solid tube designs hold collimation alot better.

So on top of your dob purchase you will definetely need a collimator.

[Tohrazer]

how expensive is a collamithingy, how hard is it to recollamything it, and how long does it take? + how frequently, oh, and what can you see?!1 thanks !

[themos]

A Cheshire collimator is not expensive, £24 new from FLO, maybe £14 second hand. It's very easy to collimate the primary, takes a few minutes. The secondary is a bit trickier, I've never done it. I do primary collimation on every session.

[kniclander]

awesome, thanks! dont suppose you could describe what views of different things look like? globulars, nebulae, open clusters? do the young open clusters look blue and beautiful?

yes the things you see are beautiful but in a kind of understated way - vision plus imagination = beauty :scratch: (if you get what I mean). to my mind, galaxies are the best cos they are so far away but open clusters are the prettiest - not all blue but all different colours. And the moon is great too.

I have a 10" dob - collimation is tricky til you get the hang of it - the 12 will be a bit easier because of the slightly higher F-ratio. the only thing I would say is that if you don't know what things should look like it will be quite hard to tell if your collimation is good or not - that's why it can actually help to start with a smaller scope with a higher F-Ratio like a 6" F8 or an 8" F6 which won't really need too much collimating. just my opinion. Try to find Astro-baby's guide to collimating somewhere on this forum - I read quite a few and that was best.

Dan

[TheThing]

Collimation is one of those things that there is a lot of talk about. In reality, your scope won't need to be collimated all that often if you're careful with it. I have 2x 6" Newtonians and they are simply carried out into the garden and set up whenever I observe. They are stored mirror down in the corner of a room kept close to the ambient o/s temperature. Becaus of this, neither has needed collimating in over a year.

[Astro_Baby]

Andys shot glass has a vide on collimation HERE which is quite good and I used it when I learnt but it does miss a few things and so I worte a more comprehensive guide HERE which covers some of the extra topics.

Collimation is a case of practice making perfect really. Its not hard so much as fiddly and time consuming and, when I started, I did wonder if perhaps I was going insane at some points in the process. In part that was due to some pretty badly written guides that didn't explain things like the fact that a modern fast scope will show 'offset' which had me chasing my tail at one point.

I was forced to learn it when my youngest undid the spider vane screws on my telescope and also when a new telescope arrived completely out of collimation. Its a good skill to learn to be honest and nowehere near as scary as most people imagine.

Anyway those are two good guides - some people favour lasers - personally I find them more of a hinderance than a help.

How much collimation does a scope need ? My Sky-Watcher 200 was collimated and then taken down 6 flights of stairs, put in a car and driven a few hundred miles, the last few over a dreadful road, it was then unloaded and set up and collimation was perfect. Recently I took the entire scope to bits to carry out flocking and on reassembly the collimation was only a teensy bit out so it should stay pretty close for most of the time unless you really bash the scope about ( mines a solid tube ).

What do things look like ? Smaller than you might hope but awesome just the same. Open clusters are my faves ( galaxies and nebulas aren't called faint fuzzies for nothing ). Some of the clutsres look amazing. While the faint fuzzies are in some ways a bit underwhelming I find them fascinating in their own way and doubles with color are also very wonderful. Sadly I dont get much time to use my kit at the moment.

[Tohrazer]

thanks guys, all very helpful!