GSO 12" f/8 RC

[Moon]

Looks like this scope is getting closer to reality - GSO have listed it on their site (http://www.gs-telescope.com/content.asp?id=158) (with no info)
It's also listed on Astronomics (http://www.astronomics.com/main/product.asp/catalog_name/Astronomics/category_name/U5QNWB3RKWWL8N3EL99F9DX9A0/product_id/AT12RC)and mentioned on Andrews (http://www.andrewscom.com.au/site-content-section-10-guansheng.htm#cassegrain) at AUD$4000
More interestingly is the promise of a matched large aperture field flattener from Astronomics (http://www.cloudynights.com/ubbthreads/showflat.php?Cat=&Board=cat&Number=4391428&Forum=,All_Forums,&Words=&Searchpage=0&Limit=25&Main=4346679&Search=true&where=&Name=3815&daterange=&newerval=&newertype=&olderval=&oldertype=&bodyprev=#Post4391428).

James

[gregbradley]

That's amazing. A 12.5 inch RCOS with corrector is over USD$20,000.
Plus shipping, plus GST, plus insurance etc etc more like AUD$25,000.

From what I have seen from many images now the optics on these GSO must be quite good.
Diffraction limited?

Greg.

[TrevorW]

Carbon fibre can't be far off probably add $2k

[allan gould]

Seriously thinking of such a scope. One question though, is there a reducer that will cover a qhy8 sized chip on the Market?

[telecasterguru]

Apparently there is a 16" on the way as well. I might wait for that to turn up. Supposedly by the middle of the year.

[Moon]

This is a good question.
Wolfgang Rohr has posted test results from an early (prototype?) 8 inch f/9 (http://translate.google.com/translate?u=http%3A%2F%2Fwww.astro-foren.de%2Fshowthread.php%3Fp%3D392 10&sl=de&tl=en&hl=&ie=UTF-8) and a later model 8 inch f/8 (http://translate.google.com/translate?hl=en&sl=de&tl=en&u=http%3A%2F%2Fwww.astro-foren.de%2Fshowthread.php%3Fp%3D474 40). I haven't seen any other tests of this type published.
Personally I find that the process of translating the reports from German make it very difficult/dangerous to draw conclusions.
For example, in the second report the Strehl ratio is reported as 0,852 and 0,984. The second number presumably with astigmatism removed - but what does that mean exactly? And there is discussion about GSO mirrors being 'rough' with characteristic radial lines, but the f/8 sample is somehow smoother that the f/9.
Do we have any German speaking opticians who can help us out?

I also understand (again could be wrong) that some GSO parabolic mirrors have tested very well (http://www.astro-foren.de/showthread.php?p=35463) in the past, so does this skill translate across to RC mirror fabrication? I don't know.
James

[gregbradley]

I am sure the AP67 reducer would work. That was standard during the ST10XME camera days for the RCOS scopes.

Greg.