5 December 2020 at 2:36 pm #574815
I’m giving away my 1980’s 250mm f4.3 Newt and planning to upgrade to a 12″ or 14″.
I know Skywatcher make 12″ Newts and Orion (UK) make 12 and 14″ plus others, but apart from those, does anyone else make tubed Newtonians of that size anymore?
I don’t really want the long focal length of an SCT (lovely though C14s are – the field of view wouldn’t be great with my Starlight 694) so I am wondering if I am out of alternatives.
Has anyone any thoughts on the suppliers of larger non-Dobsonian reflectors?5 December 2020 at 3:56 pm #583460Eric WatkinsParticipant
I have used David Lukehurst (UK) to make me a well made Truss OTA for a 16″ F:6 Newtonian which is mounted on a Paramount ME. He is associated with Dobsonians usually, but was able to make up this for me. It will see first light any day now. He’s a lovely chap to deal with.
Eric5 December 2020 at 5:10 pm #583462
Do let us know how it goes….6 December 2020 at 9:34 am #583469Dr Paul LeylandParticipant
What is your budget, roughly?
Are you wedded to any particular optical design (Newtonian, CDK, etc) and any particular mount (alt-az, GEM, fork …)?
Why does it have to be a closed tube? I used a Beacon Hill 18″ Dob very successfully back in the late 80s with a fabric shroud to keep out background light. It had the advantage of no tube currents.
http://beaconhilltelescopes.org.uk/ are still in business and they still ship up to 12″ with a solid tube. You could ask about larger ones.6 December 2020 at 10:11 am #583471Martin MobberleyParticipant
As you say, Skywatcher and Orion Optics are probably the first choice people. I’m very happy with my 12″ f/5.3 Orion Optics Newt and the 12″ f/4 Skywatcher Quattro, though heavy, looks like an absolute bargain! Have you looked at the Teleskop Service pages? They show a few 12″ and 14″ tubed models. Their ONTC models have 3 mirror positions for moving the focus in and out if required. Focusers and other bits are customisable. Of course, given Brexit looming who knows how that might affect prices/delivery from Germany?! On the same page (at the bottom) they have the Boren-Simon PowerNewts (up to 12″) which are f/4 in length but have a 0.7x reducer to give f/2.8 across a 25mm diameter field. The TS page is here:
Martin6 December 2020 at 12:20 pm #583472
Thats interesting. I had forgotten the TS scopes. Happily you and someone else have reminded me. I’ve no idea what the quality is like so I shall look into that as I had assumed (erroneously) that they were daft expensive.
I have wondered about the 300PDS from Skywatcher. The focuser is a bit heavy (I used a 130mm version a few years ago) as I recall but given I only have a 2.1m dome to work with, that may work in my favour in countering the mirror weight… The Quattro isn’t bad in that respect.
The PowerNewts are worth knowing about – I imagine collimation could be fun. Thanks6 December 2020 at 12:55 pm #583473
The constraints are: needs to be operable in a 2.1m dome, plus no more expensive than an 11″ RASA and with at least as much light grasp. I’m using an EQ6Pro, so I know I probably need to upgrade to an EQ8 – though I kind of hanker after a MyT as I have found MEIIs a joy to use, but too damn expensive.
I like the RASA that I occasionally use – a lot. Its given some great wide FOV images, but I’m not really planning to spend all my time going after large sprawling nebulae and find I tend to image smaller objects and so end up cropping the frames hugely. Obviously, a 14″ RASA would be better with more light and a smaller FOV) but they are $12k so thats not happening and it might not even fit anyway
The balance point on open truss systems seems further away from the tube midpoint to me (I could be wrong) and with a 2.1m dome I’ve got to be really careful hence ignoring them at present.
I had the opportunity to use Meade, Celestron and Skywatcher 12″ Dobos next to each other about 10 years ago. None of them gave a less than nice image though, one did excel – I need to go back and find my notes to remember which it was.
A lot of you will of course have bought new telescopes frequently, but for me this is a new experience. I bought an 8″ f8 Fullerscopes second hand in 1985 and a used 10″ AE f4.3 Newt in 2002 and thats my lot, so you can see, the instruments I have used most over the years have been old-school. I did have more ambitious plans but, as always seems to happen, events occurred (chimney in need of a complete rebuild and new car needed) which suck up the spare funds. Probably just as well as a 3m automated dome, Paramount MEII, RASA 14″ and QHY600 would dent the bank account somewhat and cause plaintive wailing from my bank manager.
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