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Thinking about changing my 8” Celestron for a larger aperture Dob.


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I'm a proponent of waiting and seeing on the eyepiece front. 

6 hours ago, bosun21 said:

This type 

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I use this one:

https://www.diy.com/departments/mac-allister-non-foldable-hand-truck-250kg-capacity/1357679_BQ.prd?storeId=&&&gclid=Cj0KCQjwlPWgBhDHARIsAH2xdNfAst_f740Qa8GeonZoF4h27LFUbjvZ7nHQAPO-tClsVaPjM_KLzdcaAmZ0EALw_wcB&gclsrc=aw.ds

So long as it's got the fold out toe plate you should be okay.

Get some bungee chord the hold the tube.  I put some bits of foam pipe lagging on my sack barrow to soften it up.  When I move it I have the tube point towards me and secured by the chords.

You will need longer rubber feet if you get the Stellalyra.  I couldn't find any so I used a few penny washers to act as spacers.

Edited by Ratlet
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Regarding eyepieces for the Stella Lyra 12” dobsonian the 30mm SuperView and 9mm it comes with are relatively poor and you should consider upgrading. They will tide you over at the start though. Regarding a Paracorr? It’s not required with this scope.

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The Kelling Star Party will take place in a few weeks and it’s only a 15 min drive for me so looking forward to attending. With any luck I may come across a 12” dob which would be very handy for me to be able see its size, hard to judge from images only. No doubt I will see some SGL members there but I wouldn’t know them if I saw them as I only know them by their username and avatar. Hopefully conversation should solve that.

I am looking forward to the Kelling Star Party, only a few weeks to go.

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Will it (base) fit though the back door... Can I lift the bloomin' thing etc. 🤪

Maybe "collimation"? As owner of a stick & string TS 8" f/4 "Astrograph",
I'd be reluctant to go faster than f/5. Difficulties as the "cube" of f-num? 😉

P.S. In another life, I sense I'd try/use above 8" Newt on my Sky-T mount.
The stars did look temptingly BRIGHT when I looked through it visually. 😎

Edited by Macavity
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54 minutes ago, Moonshed said:

With any luck I may come across a 12” dob which would be very handy for me to be able see its size, hard to judge from images only.

This may come across as overly blunt towards an obviously experienced astronomer - but please understand it's not intended in that manner.

The above words also suggest you've not yet looked through a bigger dob yet either? And you mentioned the purchase can only take place once all your current equipment is sold. If so it would be highly recommended to do some actual observing through one at Kelling also. Just to be 100% sure that theory matches expectation.

A cautionary tale to share in case it turns out to be any way relevant to your own situation and circumstances.

Your intended trajectory mirrors my own to some rough degree. I had many happy years with a manual 8" dob. It was easy enough to move around, quick to setup, and gave outstanding clear, detailed and sharp views at f/6. Then, one year, aperture fever bit and I upgraded blindly to a 10" dob with goto. Sure it was better but not nearly as better as I had expected. It's so much heavier. I'm not a weak person but my back issues mean lifting in just slightly the wrong way puts me in pain for days - plus the years are not batting in my favour anymore. I built a makeshift dolly for moving it around but that didn't completely remove the lifting nor particularly ease every aspect of the handling. At f/4.7, sharp pin-point views across the field were now gone compared the f/6 scope. Which also meant nudging more frequently to keep planets within the central field.

In summary, the trade-offs - for own my personal situation and requirements - weren't worth it and pretty much stopped my dob observing stone cold dead. Itch scratched it's now reserved for occasional use on demanding targets and/if I can be bothered.

Of course, there's many variables here so make the choices that best fit with you. I'm just chatting for the community fun of it rather than it being any earnest suggestions or direction.

For what it's worth, after eventually accepting I was never gone to use it frequently anymore, during which I lost several years observing, I went a completely different route. A small mak for planets and a small refractor for wider views, all on a super-light and portable AZ goto mount. Ticks all the boxes for me except aperture and for that I might now investigate some simple live EEA for DSOs.

 


 

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I wouldn’t be put off by other peoples experiences with a 12” dobsonian. If you are reasonably fit and mobile then with a sack trolley it’s no more of a problem than wheeling your trolley around a supermarket. Regarding the f ratio I also wouldn’t go below f5 which is what the Stella Lyra 12” is. I agree that you should try and view one in the flesh so to speak, and judge for yourself. I can easily remove the tube from the base with the aid of two wrap around carry straps and then place the base onto my EQ platform. It’s like everything in astronomy, what suits one person will be totally unsuitable for another. Good luck.

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3 hours ago, Moonshed said:

The Kelling Star Party will take place in a few weeks and it’s only a 15 min drive for me so looking forward to attending. With any luck I may come across a 12” dob which would be very handy for me to be able see its size, hard to judge from images only. No doubt I will see some SGL members there but I wouldn’t know them if I saw them as I only know them by their username and avatar. Hopefully conversation should solve that.

I am looking forward to the Kelling Star Party, only a few weeks to go.

Perfect idea - and who knows - you may appreciate your C8 setup more.

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Allow me to present an alternative view.  It's not better or worse than Jules's, just different 

Firstly, I have a genetic condition that badly affects my muscles.  In fact, on bad days I don't even have the strength to lift a mug of tea. 

On good days though I have almost full strength.  However, even then my back and neck are badly shot to pieces.  Like Jules, if I lift the scope or mount in the wrong way I'm out of action for 10-14 days.

I wasn't able to attend star parties but instead whilst in Germany visited several telescope shops.  There I was able to directly compare a large number of makes, models and sizes.

The first thing I decided was that Go-To wasn't for me because of the extra weight.  It meant that I'd have to go down a size.

I also found that it wasn't just the weight that was important but the footprint of the mount.  Having a less bulky mount meant that I could hold it closer to my body, meaning less leverage and less pain.

By far the best DOB mounting was the OOUK one.  Being made of aluminium it's a lot lighter, plus the footprint is much smaller.

Additionally, they have large circular altitude bearings in a ring shape.  These make an excellent handle, and I found that I could cope with a mount one size bigger as a result.  The Bresser (Explore Scientific in the US) is similar, but not so light as it's not aluminium.  This design of bearings also make these two makes particularly smooth.

The VX series of Dobs from OOUK also have aluminium tubes, so are lighter than the normal steel.  

The conclusion I came to was with OOUK Dobs, and to a lesser extent Bresser, I could cope with one size up compared to Skywatcher and GSO (the latter manufacture many of the generic makes on the market).

I ended up deciding on a 10 inch OOUK Dob, but couldn't justify a new one.  Used models in this size proved very hard to find, but I did get hold of an 8 inch f/6 very quickly.  However, it took me over a year to find a 10 inch f/4.8.

Since then I've had plenty of opportunity to compare the two sizes.  On the planets there's not been much between them because poor seeing in the UK is usually the limiting factor rather than the size of the scope.  Only on the rare steady nights has there been much difference.

It's on DSOs where the extra aperture really scores.  The difference isn't hugely marked though in my Bortle 4 skies, except that is on one class of object.  Here there's a very definite improvement with globular clusters - my favourite objects.

As a result I wondered whether to go up to a 12 inch.  So I asked OOUK to bring a 12 inch f/4 to a show last month. 

I found the jump in weight from 10 to 12 inches much harder to cope with than from 8 to 10.  Additionally, the mount was much bulkier. 

What I like with the OOUK 10 inch mount is that it fits just over my hips and thus it doesn't move around.  I find that this extra steadiness makes a huge difference when walking with the mount rather than just lifting it. 

I certainly couldn't carry even an OOUK 12 inch very far at all.

So for me 10-in is the optimum size.

Edited by Second Time Around
Clarity
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50 minutes ago, Jules Tohpipi said:

This may come across as overly blunt towards an obviously experienced astronomer - but please understand it's not intended in that manner.

Not at all, I really appreciate the points that you have raised.  I have indeed not looked through a 12” dob, the larger aperture scopes I have looked through were all SCT’s, the largest being 14”. What I am hoping for is a wider aperture than my current 8” SCT, which I have to say I find difficulty in lifting in and out of the shed, a permanent back problem being the main reason. The obvious problem with the larger aperture is the increase in bulk and weight of the scope. I am being perhaps overly optimistic in thinking a sack trolley will solve the problem of transporting the large dob, I’m not really sure it will. For example I was moving some stuff about in my garden shed yesterday, nothing especially heavy, but my back went into spasm and as I sit here typing this it is still giving me grief. This is giving me second thoughts.

I am not getting any younger, I am 77, and make no secret that I have advanced prostate cancer, hence the back problems where the cancer has eaten into my lower spine. Maybe I have left it too late, I’ve had the large aperture itch for some time now but taking everything into account and all the good advice I have received here I really am in two minds.

If I put my sensible head on I realise I should stick with what I have, better the devil you know. But if I put my daft head on I want that big light bucket!

Your comments have given me pause to think and I thank you for taking the time and trouble to give them and to share your own experiences. 

 

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8 minutes ago, Second Time Around said:

ended up wanting a 10 inch OOUK Dob, but couldn't justify a new one.  Used models in this size proved very hard to find, but I did get hold of an 8 inch f/6 very quickly.  However, it took me over a year to find a 10 inch f/4.8.

Since then I've had plenty of opportunity to compare the two sizes.  On the planets there's not been much between them because poor seeing in the UK is usually the limiting factor.  Only on the rare steady nights has there been much difference.

Thank you for all the information you have given. I was very interested to learn of your experiences in comparing an 8” dob to a 10”. I am surprised that on the planets they were pretty much the same, and  what I haven’t taken into account is the seeing conditions, it is only on very rare occasions can it be classed as good. Your comments about the difference in size and weight between the 10” and 12” was also very interesting, it appears to be quite a jump up. Weight is going to be the defining factor for me as well.

Again, thanks for all the info, much appreciated.

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I've had an OO 12"F4, also a couple of 10" F4.8 over the years, as well as a 10" F6.3 for a time.

The 12" is quite a big step up in size over the 10", no doubt. The OO Dob mounts, while a bit crude, actually work pretty well.

The mount is an easy lift, and i found it quite easy to grab the 12" tube by the altitude rings and shuffle along a short distance with it.

OO have a new range of Dobs, i'm assuming to update the VX range : have you seen them ?

I also wanted to stick to a 1200mm focal length, rather than 1500 / 1600mm etc because i like those rich field, low power views that Dobs excel at.

I never had much joy with planetary obsevation, just because i was always hampered by poor seeing and local conditions, and have had much more success there with my refractors.

I've since sold my Dob, and manage quite happily with a 5.5" refractor. Obviously its not quite as good at DSO, but its certainly no slouch there either.

All depends on your viewing preferences. But you have good sky's there in Norfolk, so it makes sense to exploit them with some aperture.

 

 

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18 minutes ago, Moonshed said:

Not at all, I really appreciate the points that you have raised.  I have indeed not looked through a 12” dob, the larger aperture scopes I have looked through were all SCT’s, the largest being 14”. What I am hoping for is a wider aperture than my current 8” SCT, which I have to say I find difficulty in lifting in and out of the shed, a permanent back problem being the main reason. The obvious problem with the larger aperture is the increase in bulk and weight of the scope. I am being perhaps overly optimistic in thinking a sack trolley will solve the problem of transporting the large dob, I’m not really sure it will. For example I was moving some stuff about in my garden shed yesterday, nothing especially heavy, but my back went into spasm and as I sit here typing this it is still giving me grief. This is giving me second thoughts.

I am not getting any younger, I am 77, and make no secret that I have advanced prostate cancer, hence the back problems where the cancer has eaten into my lower spine. Maybe I have left it too late, I’ve had the large aperture itch for some time now but taking everything into account and all the good advice I have received here I really am in two minds.

If I put my sensible head on I realise I should stick with what I have, better the devil you know. But if I put my daft head on I want that big light bucket!

Your comments have given me pause to think and I thank you for taking the time and trouble to give them and to share your own experiences. 

 

  I know I'm going to get my knuckles rapped for this suggestion, but as you already have a 8" SCT that you obviously love, and which will give you some very nice deep sky views as well as the Moon and planets; why not go for a complementary scope that will enhance your existing set-up. My suggestion would be to go for a  Starfield 102ED refractor from First Light Optics. It will give you a lightweight set-up capable of giving terrific wide field views with seriously sharp star images, as well as being great on the moon, planets, double stars and comets. Mounted on an AZ4 the Starfield would make an awesome grab and go scope that would perform straight away without hardly any cool down time, and virtually no setting up time. May be you could check out some of the refractor threads to get some feed back on their performance.

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10 minutes ago, mikeDnight said:

  I know I'm going to get my knuckles rapped for this suggestion, but as you already have a 8" SCT that you obviously love, and which will give you some very nice deep sky views as well as the Moon and planets; why not go for a complementary scope that will enhance your existing set-up. My suggestion would be to go for a  Starfield 102ED refractor from First Light Optics. It will give you a lightweight set-up capable of giving terrific wide field views with seriously sharp star images, as well as being great on the moon, planets, double stars and comets. Mounted on an AZ4 the Starfield would make an awesome grab and go scope that would perform straight away without hardly any cool down time, and virtually no setting up time. May be you could check out some of the refractor threads to get some feed back on their performance.

I do love my 8” SCT, had it for 30 years and I have found it to be a good all round versatile scope. My problem is that for some time I have wanted a larger aperture to look through, such as a 12” dob, but they are unfortunately rather heavy.

Your suggestion is not without merit, and one that under different circumstances I  would definitely look into. Unfortunately the reality is that I don’t have the spare cash to do that, I have to sell my existing scope in order to buy another, I can therefore only have one at a time.

Thanks anyway, appreciate all advice given, it all helps.

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1 hour ago, Moonshed said:

Not at all, I really appreciate the points that you have raised.  I have indeed not looked through a 12” dob, the larger aperture scopes I have looked through were all SCT’s, the largest being 14”. What I am hoping for is a wider aperture than my current 8” SCT, which I have to say I find difficulty in lifting in and out of the shed, a permanent back problem being the main reason. The obvious problem with the larger aperture is the increase in bulk and weight of the scope. I am being perhaps overly optimistic in thinking a sack trolley will solve the problem of transporting the large dob, I’m not really sure it will. For example I was moving some stuff about in my garden shed yesterday, nothing especially heavy, but my back went into spasm and as I sit here typing this it is still giving me grief. This is giving me second thoughts.

I am not getting any younger, I am 77, and make no secret that I have advanced prostate cancer, hence the back problems where the cancer has eaten into my lower spine. Maybe I have left it too late, I’ve had the large aperture itch for some time now but taking everything into account and all the good advice I have received here I really am in two minds.

If I put my sensible head on I realise I should stick with what I have, better the devil you know. But if I put my daft head on I want that big light bucket!

Your comments have given me pause to think and I thank you for taking the time and trouble to give them and to share your own experiences. 

 

Thank you very much for the kind words.

You know, I guess you might find all your answers and info at Kelling (alas I’ve never had the good fortune to go). Nowt wrong being interested in something new and exciting!
 

If the 12” views really connect then you could investigate more deeply the ways of accommodating it. 
 

An awkward and cramped layout meant my options were limited to a compact dolly or sack barrow. I favoured the dolly as I could hold the scope directly and push. The sack barrow to me felt rather unsafe transporting a cylindrical object - especially during the tilt up and tilt down phases. The scope needs to be fully secure for this or the momentum can topple things in different directions. It’s not as convenient as moving square boxes.  I abandoned  the idea after the initial feeler attempts purely and solely because the swift and random body movements to grab and stabilise the scope (sometimes) during the tilt/release were exactly what my back couldn’t cope with. 
 

However, you may have more room available and therefore more options to use something much better and more secure. And that could be a great match if you like the big dob views.

Best of luck with it all :)

 

 

 

 

 

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