200P Dobsonian questions, queries, concerns.

[Sobel]

Hi there, registered on here fairly recently and just first off wanted to say the wealth of knowledge in here is extraordinary, many thanks to all who share their knowledge! Anyway I appreciate this gets asked a lot in here so I apologise for the wall of text.

I've been using 10X50s bins for the last few years and think it might be finally time to get myself a telescope. So first of all a quick background as to where, why how.

• Will be kept at my dads house, with decent views in the rear garden from the NW through to the SE and relatively dark skies (can just about make out the milky way on a good night)
  
• Portability is on the list, but something that me and my dad can lift/move and transport in the car, so 8" tops imo for aperture.
  
• Cost, £500-£600 all in, eyepieces etc.
  
• Planetary and general DSO, Messier catalogue etc. basically an all rounder.
  
• No photography in mind, ever.
  
• Want something easy to set-up and get going.
  
• We both wear glasses, so eye relief if a big thing for us.
  

Now I listed all the needs/requirements with my dad and we came to the conclusion, from reading posts on here, that an 8" Dobsonian would be ideal for all round purely visual use. And at the moment it seems that's the route we're going to take. Our second choice is a lot more expensive and is a Celestron Nexstar 8SE. Our third choice is the 8" GOTO dob, it's third because if we're spending near a grand we may as well go all out and buy a SCT.

I do however have some vast gaps in my knowledge and no practical experience yet (will hopefully start going to the Bolton Astronomical Society) so need to ask a few questions, both from my perspective and my dads.

• We're no experts on the night sky by any means and as such we're curious as to how quickly planetary view at high magnifications will need nudging. I've read that say we were to use a small eyepiece, say a 6mm WO SPL, at 200X magnification 55 degrees, practically will we be nudging the dob what, every, 10 seconds? 30 seconds? every minute?
  

So from what I understand at 200X with a FOV of 55 degrees, that gives 0.275 degrees field of view of the night sky, so the earth rotates 360 degrees every 24 hours, therefore 15 degrees an hour and therefore 0.25 degrees a minute. So am I right that a view if Jupiter or whatever object in the eye piece, if starting at one edge, will require at most needing to be realigned every, say 60 seconds? And less at higher magnifications?

How do people find high magnifications with the manual dobs? Is it hard to keep a steady view? I've already read about people using turtle wax on the base to help the sticking when rotating the base, but would be something to address if/when we buy our scope. And ultimately we are happy to pay more for a goto system if peoples experience of them are that it's a must have for newcomers wanting to explore the night sky and to provide tracking. Additionally I know for my dad a goto system would probably be more fun, I like searching the night sky looking for stuff, him not so much.

• I haven't got the foggiest about eye pieces that might complement the fast f/5 dob and offers good eye relief. I imagine I want maybe 3 eyepieces to start off with (quite happy to replace the default EPs that come with the scope and the eyepiece guide on here was massively helpful ) and from reading we might look at a 6mm / 12mm / 25mm, now the 6mm I imagine would be focussed on planetary, and small DSOs? so something like a 6mm WO SPL, would that make sense? the 12mm could be maybe a Celestron X-cel LX? And maybe look at a WO SWAN 25mm? ALl of which don't break the bank.
  

I know I'm probably focussing on the wrong things for now, but after about a year of debating we took a long hard look and the above were the areas we haven't been able to address satisfactorily due to no practical experience so I just wanted to see if my train of thought wasn't too far off the mark.

Many thanks,

Oh and TL;DR (too long didn't read)

1. Manual 8" Dob or GOTO?
   
2. 6mm/12mm/25mm Eyepieces to start, budget friendly versions, William Optics SPL and SWAN as well as Celestron X-Cel LX, decent enough for 8" Dob f/5?
   

[scarp15]

I have to say that for observing planets I do prefer tracking - when using medium / high and high power eyepieces. I have a Celestron C8 Celestar, a predesessor to the Nexstar, nice and simple to use, my version tracks with a 9 volt battery in Right Ascension. I purchased mine second hand, which could be an option to.

As you have emphasised observing planets, with general DSO'S then an 8" SCT will be my preferred choice. It will also be more forgiving with your choice of eyepieces. GOTO is perhaps not essential, a telrad, finder charts, a copy of 'Turn Left at Orion' and Stellarium are the tools to get started with.

An 8" F5 dobsonian though will be simple and easy to operate and nudge and will provide the more cost effective option, and if used with wide field eyepieces of a good quality (again could be sourced second hand) would still allow you to adaquetely track, at least in medium power, objects such as the planets.

[Capricorn]

You seem to have it all, right about the angles and drift.

If you got the goto of any sort then you need power as well, you mentions it being transportable and so you need to transport the power also.

CAtch is that with the classic dobsonian you find everything. Do not expect anything to jump into your view, they tend to hide. If your father finds anything then if you swap expoect whatever to not be in view. Tiny angle here is a big move up there.

Eyepieces try the BST Explorers, good and good on f/5 and f/6 scopes.

So budget for 2 or 3 of these and a collimator to keep everything aligned, say £200 on top. Expect that that makes a difference.

[scarp15]

Just noticed that this is your first post - welcome to the forum, and if you do get along to your local Astronomical Society, this may be the best source for good advice and trying out equipment.

[CFC]

If your dad is not interested in finding objects, just in viewing them, I think you have no idea of how bored he would get with a dob within quite a short time. In your situation I'd very seriously consider a GO TO.

[jimmyjamjoejoe]

For the record, the dob is an f6. You seem to be on the right track and know what you want.

Personally, i dont mind nudging at all. Dont get me wrong, i'd love tracking, but i wouldnt want to pay hundreds more for it. In the 200p, 8mm is around the sweet spot for magnification. Some nights can give more, but 8mm is the regular for planetary.

The BST range (starguiders), are good value for money, giving good views with a decent field and very comfortable eye relief. To start with i'd get the 8mm bst and a decent widefield low power ep, around 32mm. I can wholeheartedly recommend a baader aspheric 31mm, though it is a little pricey at ~£130.

As for finding stuff, it's easier than you think, though using the finder can be tough. Personally i prefer a red dot/telrad. You can get in the general area with that, then fine tune with the low power ep, since it shows a pretty large area of sky.

There's no harm in trying stuff out in this hobby, kit holds it's value pretty well and can be resold with very little lost. Also, alan at skies the limit offers a no quibble money back thing on his eyepieces, so you can try them out and send them back if they arent what you like.

[Scott]

Just to throw a cat among the pigeons. If you dont mind finding things and by the sound of it your dad does. The 200p on eq5 is about 400 pounds, add another 100 for tracking motors (not goto) then you're up for 500. I don't know how this compares with the goto dob but I find for planets, tracking does make the whole experience a lot more pleasant. Just a thought.

Scott

[umadog]

I think an 8" Dob is a great starter scope for all objects. It's a good all-rounder. You seem to have thought things through carefully. I wouldn't worry about eyepieces right now. Buy the scope and use what comes with it. Then you can add eyepieces over the following months. Take you time with them and you'll get the right ones.

You'll be fine without tracking for a first scope. Remember that if you get into the hobby it won't be your last instrument. So buy something that's at the lower end of your budget and something that's easy to set up. This is why a Dob is a good choice. If you later want something with tracking then there're plenty of options out there. A Dob with good bearings, though, will do a pretty good job on planets.

[hwsoderlund]

About nudging a dob at highish magnifications: Personally I do not find this to be a problem any more. It was a bit of a hassle in the beginning but quickly became second nature. I don't really think about it now. Perhaps if I had previously owned a tracking scope and then switched to the dob, I would have found it more inconvenient. What I am saying is that the nudging in itself should not stop you from getting a dob, at least if you have not already gotten used to the convenience of tracking.

[cotterless45]

As a starter scope and to learn the skies the 200 Dob with a Telrad charts and a Telrad is ideal . Add the 25mm and a 12mm Bst and a Cheshire collimator, Bob's Knobs primary springs and you're off.

When you get used to the frost and the long hours, you can then get any suitable mount, GOTO or ra motorized and some tube rings and mount the ota.

This is one of the few pastimes where spending shedloads will not give you a better result as the prime factor is seeing conditions.

Nick.

[66mikeg]

I've only tried a dob once or twice and didn't get on too well tracking and viewing planets at fairly high magnifications but that's just me, for just over £400 a SW200p with eq5 equitorial mount would be my choice for visual observing it gets a good write up in most reviews and the SW200p is a great 'scope polar aligning the mount for visual isn't a big deal either.

[NGC 1502]

The above excellent posts show how hard it is to give advice, lots of genuine helpful (but different info) just as in all areas of life.

I think the best idea is to get along to the local astro society you mention, ask around, and if you can, get to an observing session. Most of the folks into astronomy are only too happy to show you their kit, and maybe try it as well. It's the least expensive way to find out what would suit you and your dad.

I wouldn't rush the decision myself.

Hope you find something that suits, Ed.

[Peter Drew]

Welcome to the forum, why not come along to one of our Saturday night observing sessions and try out a 8" Dobsonian.

[Fordos Moon]

Welcome indeed! I thought it worth a mention to anyone thinking of purchasing a 200P dobsonian to earn you it no longer includes a Barlow or the white plastic caps to protect your screws from the elements :-(

[Ganymede12]

Recent;y upgraded to the Skyliner 200p myself. I jumped up from a 70mm refractor and the difference was amazing! I was lucky that I got It cheaper off Classifieds

Here's a thread I started a while ago when I was asking questions about the Dob. You may find it useful

[Grommie]

Have to say I am in total agreement with NGC 1502 above...As a newcomer myself there is SO much advice here (all valid but people have different opinions) you need to try options before, like me, you make a big mistake. My local astronomical society has equipment you can borrow and get a feel for what will work for YOU. I'm sure there'll be something similar you can join in your area....A great source of problem-solving! Good luck.

Just noticed NGC 1502 has a Televue Pronto so he DEFINITELY knows what he's talking about. Guess what I've got??

[bingevader]

The above excellent posts show how hard it is to give advice, lots of genuine helpful (but different info) just as in all areas of life.

I think the best idea is to get along to the local astro society you mention, ask around, and if you can, get to an observing session. Most of the folks into astronomy are only too happy to show you their kit, and maybe try it as well. It's the least expensive way to find out what would suit you and your dad.

I wouldn't rush the decision myself.

Hope you find something that suits, Ed.

I agree too!

Psalm 19 v 1 splendid!

The telescope you use the most will be the one that's best for you!

Easy to say, not a thing that's easy to find out!

I've had a etx90 (goto) for over 10 years, fabulous little telescope, dead easy to use it was rarely in its case.

However, I found that I wasn't really learning the night's sky!

For the last few years I haven't been using the computer at all.

I've had a star atlas or the Sky at Night monthly guide, slackened off all the motors and just pushed the thing around.

I'd now be happier calling myself an amateur astronomer.

It depends what you want the telescope for and what you want to do with it!

I know that doesn't help, so get yourself down to a local club and try things out.

Cheers

[ollypenrice]

You've done tip top homework and homework will take you no further. You need to try the kit. I left Bolton a long time ago (Bolton School, left 1972!) but I have a simple faith that the AS would do you proud in letting you try what they have.

The various scopes have Fors and Againsts and in the end it is you who must decide. I could give you my preference but what good would that do? My guests and astro friends would not agree with me or each other!!!

Try the kit at a club.

Olly

PS, Never any astrophotography? Hmmm, I said the same. http://ollypenrice.s...44788&k=r8HTK72