Quote:
Originally Posted by LewisM
Which would win in your opinion - a fluorite 102mm of a VERY high quality brand, or a 127mm ED of a good Chinese brand. The 102 is f/9, the 127 is f/7.5 (and comes with a further FR etc)
My ONLY application is astrophotography, with OCCASIONAL visual.
Just a real bugger deciding right now!  |
Hi Lewis,
I know nothing about astrophotography, but I know quite a bit about the Vixen FL102S and I assume that is the 4"/F9 Flourite you are considering.
The Vixen FL102S is a very high quality flourite doublet, notwithstanding it is a 10 + year old optical design. It is optically the equal of scopes like the Takahashi FS102 and at least as good as the Televue 102, which are from the same generation. The Tak FS102 is F8 and the TV102 is F8.6. It's about as good as you will get out of a doublet APO. At F9 its fairly slow by todays APO standards and because it is a touch slower, colour correction is excellent for a doublet.
One big advantage of the Vixen FL102S is that the tube is smaller and lighter than most other 4" refractors, making it easy to handle, transport and mount. One negative of the Vixen FL102S is that the standard Vixen focuser is a bit of a lemon and most owners upgrade these to an aftermarket focuser like a Feathertouch or a Moonlight.
I am guessing you could pick up a 2nd hand Vixen FL102S and install a new focuser for well under $2,000; if the focuser hasn't already been upgraded. The 127ED APO is going to cost you $2k with a Chinese focuser still on it. It will also be a bigger scope phsically. Hard to know how they would stack up optically but with any optics out of China the good ones are pretty good, but there is also a chance of a lemon slipping through the cracks.
With the Vixen "it will just work right". One of my very favourite 4" scopes in fact.
Cheers,
John B