Fast imaging scopes?

[rocketandroll]

That's awesome Olly, definitely want one :-)

Howsabout this:

Canon 200mm EF f2.8 L USM MKII Lens

The original link was to an old (but good condition) Canon FD (35mm) fit 200mm f2.8 prime lens which I could attach to the Eos with an adapter with no problems.

If I put 'Canon EF200L' into Google I just get LOADS of pages for the £5K USM lens. £500 = win £5000 = fail :-)

Ben

[rocketandroll]

... actually, just found another two on sale, second hand around the £450 - £490 price mark, here's what it's described as: Canon EF 200mm F2.8L 11 USM

Is that the right one?

It's the only f2.8 200mm EF fit prime I can find other than the aforementioned megga-bucks USM one.

Ben

[michael.h.f.wilkinson]

Thanks for all the advice Michael!

Just looking at all options...

what about something like this:

Ritchey-Chrétien telescope 8",f/8 RC Astrograph on eBay (end time 02-May-11 11:38:40 BST)

With a focal reducer? Would a focal reducer designed for an SCT type scope work with this?

Dunno if I'm totally barking up the wrong tree? :-)

Ben

There are purpose-made focal reducers for GSO RC scopes found here. These do not cost the earth, and turn your F/8 into a more respectable F/6.

[ollypenrice]

That's awesome Olly, definitely want one :-)

Howsabout this:

Canon 200mm EF f2.8 L USM MKII Lens

The original link was to an old (but good condition) Canon FD (35mm) fit 200mm f2.8 prime lens which I could attach to the Eos with an adapter with no problems.

If I put 'Canon EF200L' into Google I just get LOADS of pages for the £5K USM lens. £500 = win £5000 = fail :-)

Ben

The link is good. That's yer man!!

Olly

[Whippy]

There are purpose-made focal reducers for GSO RC scopes found here. These do not cost the earth, and turn your F/8 into a more respectable F/6.

I believe those reducers aren't available any more unfortunately, the Intes reducers are only 6 euros more thankfully!

Tony..

[rocketandroll]

Thanks Olly, figured that must be it :-)

Found one second hand in good condition for £470. Gonna snap it up tomorrow I think.

Sorry, kinda hijacked my own thread veering from high magnification fast scopes to widefield camera lenses :-)

Cheers Whippy re: the reducers, no probs... tbh I think I'm gonna have a stab at getting the right reducer for the Meade 127mm Apo first, see what that does before I go swapping scopes and regretting it.

Thanks again all for the advice!!

Ben

[Catanonia]

Re-opening this thread as I will soon be getting my Boren F2.8 reflector and will post the results.

[Jessun]

Ben here are two reducers that might work just fine. I intend to get one of them for my RC, but can't decide which one...

If it comes up in German just find the tiny British flag to get the translation.

https://www.teleskop-express.de/shop/product_info.php/info/p3823_GSO-2--0-75x-reducer-corrector-for-RC-telescopes.html

https://www.teleskop-express.de/shop/product_info.php/info/p4955_Astro-Physics-CCDT67-0-67x-Reducer-2----e-g--for-GSO-RC.html

Cheers

/Jesper

[michael.h.f.wilkinson]

Ben here are two reducers that might work just fine. I intend to get one of them for my RC, but can't decide which one...

If it comes up in German just find the tiny British flag to get the translation.

https://www.teleskop-express.de/shop/product_info.php/info/p3823_GSO-2--0-75x-reducer-corrector-for-RC-telescopes.html

https://www.teleskop-express.de/shop/product_info.php/info/p4955_Astro-Physics-CCDT67-0-67x-Reducer-2----e-g--for-GSO-RC.html

Cheers

/Jesper

These are the same I noted above. Some people claim you can no longer get them, but TS seem to think otherwise.

[Jessun]

Oops, must have missed that line....

/Jesper

[Psychobilly]

No more single use scopes for me it will be camera lenses from now on...

A more expensive option but at least they stand more of a chance of being used..and it turns out that its widefifield that "floats my boat"

Initial astro tests of the Canon 100-400L look promising and its very nice for terrestrial use as wwell ...

Fine focus of camera lenses on the canon DSLR's is a doddle with a computer and remote manual focus combined with zoomed liveview

Peter...

[michael.h.f.wilkinson]

For wide field, I could put my old 1.4/85mm Zeiss Planar for Contax on a Canon EOS, for really fast, really wide field imager.

[ollypenrice]

Looking forward to these results.

Olly

[michael.h.f.wilkinson]

Long time back I made this on 100 ASA Fujichrome, unguided using my GP-C8 with a Contax RTS-II in piggyback configuration with on manual bulb setting, 12 min exposure.

It is the result of a slightly dubious scan of a print of the slide, so all sorts of artefacts appear. But is does show decent round stars to the corners. An APS sensor would use a smaller area.

[ollypenrice]

Excellent, Michael. I think of you as Mr Visual but that says otherwise!!

Olly

[michael.h.f.wilkinson]

Excellent, Michael. I think of you as Mr Visual but that says otherwise!!

Olly

Thanks. The scan does not do the slide justice. I must get a better scan some day.