Which second scope?

[sedm1809]

Hello,

Fifteen years ago, when I was still at school, I bought a 4.5" Newtonian reflector on a basic EQ mount. I didn't get much use out of it as I never really had a proper plan of what to look for. Since then I have moved around a bit but always in flats in city centres so the scope stayed in the loft at my parents. A year ago however I moved into a place with a garden so thought I'd retrieve it and try again. Anyway, I've had much more fun and success this time round - with the help of a red-dot finder, some upgraded eyepieces and the internet.

So I've now got to thinking about getting some more powerful equipment. There is plenty more to see with my current setup, but I'm aware that it has several limitations: obviously I'd like more aperture, the mount (EQ1) could be sturdier and also the model is a Bird-Jones design which I understand is generally considered inferior. It has a spherical mirror with no centre spot.

I like the equatorial system of mounting, and think I have pretty much decided to upgrade to an EQ5. However for the tube I am undecided about whether a 6" or 8" would be the best step. I can keep it set up by the back door so I can fairly easily get it outside, however I think anything larger than 8" will be too unwieldy. My real question is: in a suburban, back garden observing scenario, will an 8" really be worth the extra cost and loss of practicality, or will it just enable me to see more light pollution?

 

[nightfisher]

You would be best just answering a couple of questions before we can give proper help......

What sort of budget are you looking at spending?

what objects do you prefer to view, i.e deep sky or planetary?

It sounds like you prefer to stick with a newtonian reflector ?

I feel that an 8" is a bit to big for an EQ5

[Knighty2112]

I used to have a 6" Newtonian, but whilst the views where good the tube assembly was too cumbersome for me, so I eventually went for a second hand C8 SCT, which gives great views and is much easier to manage. In fact I can carry the scope & the Celestron SE goto mount it normally sits on very easily in one go out in to the garden, something which I couldn't do with the 6" Newt which had to sit on either an EQ mount (which I don't like at all I'm afraid), or one of my AZ mounts, and had to be a two trip job to carry outside and set up. New SCT's are more expensive than Newtonian's in general (there are exceptions of course!), but the benefits of larger aperture with a much smaller size with the SCT easily out weigh an downsides in my eyes. Worth a thought maybe. 

[Mark at Beaufort]

@sedm1809 welcome to SGL. I think the questions raised by Jules will give us a better chance of suggestion the most suitable telescope and mount. I understand there is also a very active astro society in Bristol which you may wish to look up.

Certainly the suggestion of a SCT by Gus is a very nice scope and has been popular for many years as a good general purpose instrument allowing views of Planets, Moon and brighter DSOs.

[Ben the Ignorant]

Let's say you compare two f/5 scopes, a 200mm/1000mm and a 150mm/750mm, the larger one will magnify more with a given eyepiece because it has a longer focal length, thus exit pupils will be the same, thus you won't just see more light pollution will the bigger scope.

Because the extra magnification will spread light pollution more, so it doesn't matter if the scope takes in more of that thing. This is true of any setting with any level of light pollution, more diameter always shows more. Get the larger scope if you and your mount can handle it. Plus, a 200mm scope will have a 2-inch focuser that will allow very long focal length eyepieces in order to obtain wider views.

When you look at faint things it's essential to receive as much light from them as possible.

[pete_l]

Personally, I would not find much difference between a 4½ inch and a 6 inch reflector. So I would not feel that upgrade was worth making a change for. An 8 inch however has 3 times the aperture and is therefore getting into "different world" territory. It is undoubtedly bigger - much bigger. Possibly bigger than you would imagine if you haven't seen one before.

But that extra size and light-gathering power also means that you could fit a light pollution filter and it wouldn't leave targets too dim to see.

After that the question is: what focal length to choose?

[Macavity]

Hard to put all your eggs in one basket? After (too!) many years
"thinking", I started out with a 102mm f/5 'Frac, closely followed
by a Mak127 -- Precisely to "learn the difference"? The 'Frac was
first (with the mount!) and the Mak would *share* that. (I said)! 

Most people seem to go the "Dobsonian route" but weight and
size were a significant consideration for me -- Also field size too!
Wider fields (shorter focal lengths) make it easier to find stuff...

[Moonshane]

My most used scope is my older gold 120ed  which I bought used and my driven eq5  also bought used. Total cost about £600

If you can stretch to that sort of budget you'd have a superb all rounder.

[sedm1809]

Thanks everyone for your replies.

In terms of budget: about £500. I could stretch a bit if it was worth it. I can see an EQ5 for £245 https://www.bristolcameras.co.uk/p-skywatcher-eq5-deluxe-heavy-duty-equatorial-mount-tripod.htm with a 6" tube for £225 https://www.bristolcameras.co.uk/p-skywatcher-explorer-150pds-ota-10218-.htm and an 8" for £299 https://www.bristolcameras.co.uk/p-skywatcher-explorer-200pds-tube-assembly-10220-.htm

I definitely want to keep with a Newtonian reflector on EQ mount. I can keep the scope set up by the back door so I don't have far to get it into the garden. At the moment I just carry the whole thing in one go but I could cope with setting up the tripod/mount separately and then putting the tube in. That said, other things being equal then smaller would definitely be better.

In terms of what I like looking at - I don't have any definite preference. I have enjoyed both double stars/planets on the one hand and open clusters on the other. I think most of the deep sky catalogues will be more or less beyond what I could reasonably expect from a back garden observing environment. I have seen the dumbbell nebula but I feel that was pretty much at the limit of what is achievable with my current kit. I don't drive so can't really get to a rural or dark sky site. My current scope has focal length 1000mm and I spend most of my time with a 40mm eyepiece - I like being able to get big things like the double cluster and Pleiades into the field.

What I gather from the comments so far is that an 8" will give greatly enhanced performance whereas a 6" may not be much of an upgrade, however an 8" will be quite a bit more cumbersome and may be pushing the limit of an EQ5 mount. It would be great if I could get an idea of what improvement I could expect - given that in my 4.5" the dumbbell looks like a really faint patch of light which I can only see in averted vision and by nudging the axis controls a bit, what improvement could I expect with a 6" or 8" respectively?

It's not just about aperture - I thought getting a parabolic mirror and ditching the Bird-Jones design would also contribute to improved performance. Is a dual-speed focuser worth having?

Thanks again!

[wookie1965]

I have a  8 inch on the eq5 mount from suburban skies I have viewed loads of stuff, plenty of Messier's, NGC's, double and variable stars.

[Macavity]

I think many *modern* Newtonian / Mount packages work well enough.
Whenever I think "Newtonian", I think FAST scope e.g f/5? (Potentially) 
more expensive eyepieces. But there is a lot of advice re. that here too.