Quote:
Originally Posted by g__day
Ken,
I put a Losmandy Tak head on a Vixen Atlux (they match perfectly) to hold a Losmandy side by side bar - absolutely no flex in this - rock solid. Next I got the Losmand D saddle adapter to fit a C9.25 to one of the side saddle bars - excellent rigidity.
What I did next was a total compromise:
1. I put a 127mm MAK in the second side saddle using a pair of the largest Losmandy O rings with 3 point bolted adapters
2. I put the C9.25's original wide Vixen dovetail on top of the scope and used this to connect a Williams Optics 80mm Megrez again using a pair of three point bolted adapters.
These bolted adapters where necessary to align the optical tarins of all three OTAs to the same target, however three slim 2-3 mm diameter bolts are simply not robust enough to hold my smaller two scopes without some differential flexure - probably quite a lot.
It's the aligning the OTA's light path that kills rigidity. The only system I have heard that really works - to align two OTAs correctly yet maintain strict rigidity on both is a Robin Cassidy Tandem Guidescope Aiming Device http://www.robincasady.com/Astro/TGAD.html
They are moderately heavy and cost around $500 landed - but it seems they alone perfectly do the job.
Interested in other folks views. If you want to rigidly mount and align two or more telescopes light paths what other device can you use?
If you had a large SCT and high end mount - you could build a rigid cradle to swaddle the entire OTA and let a second or third OTA be attached to the craddle and light paths perfectly aligned (which would really cost - like high end RCs tend to do). |
Hey Matthew that looks the ducks business but a bit out of the price range at the moment, I'll just have to drool over that one.
Quote:
Originally Posted by Merlin66
IMHO I'd go for a side by side plate..
I mounted my 6" f3.8 and the ED80 on the HEQ5pro...
(I later changed over to Losmanday dovetails..)
A good rigid set-up no issues..
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Quote:
Originally Posted by Irish stargazer
I use the ADM mini dovetail on my C 11 to hold my Megrez 72 and it is rock solid.
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Merlin and John, yes I like the side by side look and I think it would be a lot more user friendly without putting the extra weight high up.
The other point I must keep in mind is that these are my first two scopes and I'm not sure where this will all end up
so don't want to spend a lot, don't have a lot to spend is the other thing at the moment.
I also like the Idea of the cradle setup, could make one of those without too much trouble.
I have one thing in my favour and that is as a mechanic I have all the tools to make almost any extra bits i need, the only thing I'm short on is a milling machine
Thanks for the input, off to Bintel in the morning so may come home with some bits to get me started.