To go or not to goto, that is the question

[milkyjoe]

I have a dilemma (yes, another noob ):

After a few years away from astronomy after having a child, I recently helped a neighbour of mine setup their new reflector telescope and this has made me want to get back into it, and now, after countless hours of research like many other users on here, I am struggling to choose what new scope to buy myself, my budget is approx £350.

I have been looking at a Skywatcher 6" dobsonian, but I first was drawn to a mak, particularily the Skywatcher Skymax 127 as I've heard good things about them, then I noticed this scope on a Supatrak and GOTO mount; and then I saw the Celestron Nexstar 127 SLT... and so on...

Is a GOTO or SupaTrak system really worth the money at the lower-end of the price spectrum or should one only be considered for serious astro work if you have £1000s burning a hold in your wallet?  Obviously, these systems need a power source of some kind so setting up might take some time compared to the dob, but I quite like the idea of tracking objects to look at; with my 4" refractor, it can be difficult to locate objects and I can be easily put off the hobby.

As mentioned earlier, a 6" dob was recommended to me by the user Charic, as you get a lot of aperture for your money apparently with these, and being pretty quick to setup compaired to others out there it seems like a good option.  My only problem/concern is I probably won't get chance to go to a dark sight so I'm confined to my back garden for observing so with a dob needing to be put on to the floor, this will limit one's viewing will it not and I don't envy the back ache either!!

Anyway, I know there is no good "allrounder" scope, but as I already own a 4" refractor, I would like something fairly decent to view the moon and planets with (and perhaps dso's ) in more detail.

I need some help please.

Thanks.

[Northern Soul man]

Hi Ya Milky - bit of a tough one mate - as you say you already have a 4" frac - so image and light grasp from a 127mm Mak or even a 6" Dob isn't going to impress you.  You will get a slightly bigger image scale on the Moon/Planets due to the longer focal length if you go with the Mak.  I observe under light pollution and before GOTO I used to struggle picking out the fainter objects - I was probably right on top of them - but due to the light pollution - not sure if they were there because of the light pollution "drowning" all but the brightest objects out.

I had the Celestron on its original mount for a while - lets say I was very impressed with the views - even when comparing them against the CPC 1100 - but I broke one of the spreader attachments (only plastic) so had to replace the spreader/tray with chain - worked ok, but you have to be careful when "spreading" the tripod legs, as not to be too heavy handed (like me).  The GOTO worked very well and was accurate.  I now use the OTA on a CG5 mount and am well pleased with the Planetary/Luna - very nice, even, to a certain extent, the smaller brighter DSO's are nice through it - but your trying to compare a 4,5 and 6" aperture - your not going to be blown away with the difference, a larger jump in aperture - say from a 4" to a 10" would be more pronounced over the whole range of different objects, but with a 6" Dob, its not going to be much of a step up from the 4" Frac - also, if you suffer with light pollution (as I do) and your going to do most of your observing under these conditions, you have to make the most of what you've got - I just concentrate on the things I can see and not worry too much about the things I can't see.

Must say though the 5" F11 ish Mak is a very nice and very capable instrument for its aperture - low maintenance, just put a dew shield on and away you go, you could carry this thing completely set up for miles, and like me, just enjoy what's up there from a Surburban (light polluted) sky.

Paul.

[nmoushon]

You have really ventured into more than just goto vs manual. You've also intered into comparing two different scopes now also. I'll do a quick touch on both, from my pov.

GoTo vs manual: Firstly I said manual instead of non-goto because there is a difference. non-goto can still have motors that will track the target for you so it stays in the FoV until you move to a different target. It just won't find the target for you.  The dob you are looking at is manual, which means you will have to constant nudge the scope to keep the target in the FoV. Both are perfectly fine just different. Now from my person experience I prefer goto over manual anyday. Or at least have the ability to track. I personally don't like nudging the scope every couple seconds (the time differs depending on your FL and EP). Now my tracking mount has goto so i've never dealt with strictly a tracking only mount but even if you have goto you dont have to use it, which I do all the time. Some people have the time and like the challenge of finding all the objects up there. Sometimes I like the challenge too but if im either not in the mood or I dont have the time (both litteral time and time due to weather) goto comes in very very handly for quickly having a go outside. Its also nice to have at least the tracking if you plan on showing off astronomy to others. You don't have to worry about the object moving out of view while people or looking or people moving it in the wring direction and then having to find the object again. (This more relates to DSOs than the moon or planets)

Dob vs Mak:  The Dob has the extra bit of eperture that could come in handy in your garden, especially if you have some LP like most of us. It also will be very easy to setup and use. But it doesnt have as long of a focal length as the Mak does. Longer FL comes in nice when wanting to look at the moon and planets as it gives a larger scale to what you see. So the Mak has the advatage there. The Mak also has a much slower f/ratio than the Dob (assuming your dob is in the F/5-6 range). The slower f/ratio is better for viewing the moon and planets while the faster ratio is a bit better for DSOs (along with the more aperture).

[Gasmac]

You could get an 8" dob for that budget.

[Davie]

Theres always second hand? Theres an 8" dob on astrobuysell for £150

[swamp thing]

Hmm! you have a 4" frac. nice sized scope.

My advice is to hang on, keep saving and look at a 10" dob as your next upgrade.

An 8' would be nice but a 10" will really give you a wow! after a 4"

[Charic]

........compared to the list?  my recommendation for the the 6" should be the minimum specification for a Newtonian Reflector. Bigger is better, especially for  deep Space Objects/  visual observations. The 8" is almost 'Perfect'........there, I`ve said it? but no matter what you purchase, there may be something bigger and better. But you have to know where/when to stop.  An 8" will bring you much joy!  On technical grounds, If I were to buy another Newtonian on a Dobsonian mount, it would be the Solid Tube, Sky-Watcher Skyliner 300P with its f/5 focal ratio. This would be easier to match your eyepieces too, compared with the 10" f/4.8?  I've no doubt, my 200P would also sell easily, Its in perfect condition.

[ronin]

The answer to this is simply which do you prefer.

Yes some of the budget goes on motors, it also does when you buy a car, I do not see many recommending a car with no motor in it.

Having that tracking is very useful, probably more so if you are actually not overly serious - centre an object, talk to a person, grab a coffee and it should still be there when you get back to looking. Even when selecting the next eyepiece and finding the thing it is useful to have tracking. Also easier if there is more then you observing through the scope to observe.

As to the idea of learning the sky I guess most goto owners have a very good idea of what is where. I have a couple of goto's and first I will check that the next object is in view and so where it is, then when the goto is told to go it is a case of it goes where expected or it is a stupid thick skinned pile of manure that should know better. Does any goto owner actually trust their goto?

As you say they all have problems or disadvantages, even if you are looking for a scope of one aspect alone. A dobsonian is said to be best for DSO's (large aperture = lots of light collection) so how about the last couple of Messiers to complete the marathon if they are down at 15-20 degrees above the horizon - work out where the eyepiece will be. My Alt/Az Mak will do horizontal easily. :grin:  So can be disadvantages even if the requirements are not excessive.

Another question is imaging?

Lost count of the number of people that only ever want to do visual and no interest in any form of imaging. Then 3 months later ask how to get images of Moon, planets and DSO's through the dobsonian they bought. If you have kids what will the situation be when one askss if you can get a picture of Jupiter for them? If not kids a friend could well ask if you can get pictures of the objects from the scope.

[CSM]

Another question is imaging?

Lost count of the number of people that only ever want to do visual and no interest in any form of imaging.

I was one of those.  Said that the last thing I wanted to do was AstroPhotography - until I looked at Jupiter on my computer screen with a webcam and saw the Great Red Spot for the first time.  Then I realised that I could 'see' far more when imaging than I could visually.

[swamp thing]

Yes some of the budget goes on motors, it also does when you buy a car, I do not see many recommending a car with no motor in it.

As you say they all have problems or disadvantages, even if you are looking for a scope of one aspect alone. A dobsonian is said to be best for DSO's (large aperture = lots of light collection) so how about the last couple of Messiers to complete the marathon if they are down at 15-20 degrees above the horizon - work out where the eyepiece will be. My Alt/Az Mak will do horizontal easily. :grin:  So can be disadvantages even if the requirements are not excessive.

Err! interesting analogy ronin not sure a motor on a scope is quite so vital  

The other point. have you used a Dob? with my 10" I can observe horizon to zenith whilst sitting on a comfy seat, without so much as adjusting it. Small Dobs don't really alter eyepiece height as much as you'd think. 

[milkyjoe]

Thanks to all for your replies.

I'm afraid I am none the wiser, I am going round in circles at the moment trying to select a new scope.  I do very much like the idea of a dob, but I'm worried it will be too big to store.  What are they like on the moon and planets as most I've seen are around and F5?

I have been looking at getting some binoculars in the mean time, particularly the Pentax 10x50 PCF WP II or Opticron Imagic TGA WP Porro Prism (10x50); are these bins any good or should I just buy a new scope instead?!

Decisions, decisions...

[bomberbaz]

Get a scope fella. The footprint on an 8" dob isnt to big. Or there is always EQ mounted but try 2nd hand first. There was a 8" dob on ukabs that sold for £225, search here http://www.astrobuysell.com/uk/search.php

There is a EQ mounted 8" one here  http://www.astrobuysell.com/uk/propview.php?view=84311

You will see 10 times more with a scope than bins. Don't get me wrong, bins are great for grab n go but a scope takes you too places that bins simply cannot

steve

forgot to mention, both adverts i saw left money over for an eyepiece or maybe 2

[nmoushon]

You could also get a collapsible dob. Maybe a bit more money but dont have to worry about storage.