I've read many good things about Sumerian scopes (especially the latest generations). There were some hiccups but they appear to have been sorted out and the production is reduced and streamlined. TS takes European orders and imposes uniform mirror choices. TS is not fun to deal with, slow to answer and the answers are terse and sometimes cryptic. Michael (who makes the scopes) does not appear to answer the mails (at least not yet to me) so I am left with the collective wisdom of the forum to pry some more information.
I understand that the 12 inch case weighs somewhere around 14kgs and the rest are truss poles. I'd be grateful if anyone comes up with the exact figure. Total weight is 16.5 as per both websites.
F RATIO AND BALANCE - Most reviews suggest that 10 inches version are bottom light and that they are not suitable for heavier eyepieces, and I presume Paracorr. 12 inches should have a better balance due to heavier mirror. Going F4 would make it more stable, sticking to F5 would make it easier to collimate, be easier on the EPs and (who knows) dissuade me from buying a Paracorr...straight away. I do notice coma at F5...
QUARTZ or PYREX - TS streamlined mirror offers to GSO Pyrex and TS branded quartz mirrors. At F5, both are available, at F4, only Pyrex. Quartz glass adds about 400eur to the bill, but the mirror seems to be 39mm thick just like Pyrex, presumably to avoid astigmatism because of the design of the cell. Lighter mirror would also be problematic because of the balance. So Quartz or not? There are fans behind, hopefully helping the cooldown and dealing with the boundary layer. Pyrex is slower to cool, but how much does that matter when you have the fans? Does Quartz offer much benefit when they are of the same thickness? GSO is Pyrex, Quartz is TS branded, anyone had any experience comparing them?
So here are the options:
F5 and Quartz - more expensive, faster cooldown, easier on the EPs (although mine are all TV in 7-24mm range). Might still itch for Paracorr on top of it, adding to the bill. I know I will, sigh. Less stable than F4 balance-wise, although T6 plus Paracorr is almost like an Ethos.
F4 - more stable, more demanding on EPs, Paracorr a must (there goes the balance advantage, although still less strain than F5 with Paracorr). Pyrex only, slower cooldown.
F5 in Pyrex, easier on EPs than F4, easier collimation, slower cooldown, again Paracorr dilemma. Price pretty much the same like F4 Pyrex.
EQ Platform or not? Sumerian platforms are listed at 2 kgs weight...I find that hard to believe.
What are your thought and suggestions?