8" Zerochromat....

[Stu]

Intriguing looking scope. I've read about these before, anyone seen one?

http://m.ebay.com/itm/281276395442

It seems to be from this company:

http://www.firefly85.com/index.html?m

I guess they are effectively just folded optics, long focal length refractors.

Stu

[John]

I've read lots about them but I've never actually seen one.

I believe the design uses a singlet objective lens, mirrors to fold the light path and a sub-aperture correcting lens set somewhere in the light path. 

There is a Cloudynights thread on it here with contributions from the designer / vendor:

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5940892/Main/5928950

Intriguing design - I assume the correct alignment of the mirrors and lenses is critical ?  

[YKSE]

@John, as a Refractor man, isn't this the biggest portable refractor you can get?

[Mr Spock]

Those folded optics look difficult to collimate. The tube dwarfs the EQ6 too.

Don't fancy this at all

[John]

@John, as a Refractor man, isn't this the biggest portable refractor you can get?

I reckon it must be. It's a 10kg tube apparently which is very light for an 8" refractor. I'd love to try one but I'm not sure I'm confident enough to consider investing in one

Istar do an 8" F/8.8 which weighs twice as much as the Zerochromat so you can imagine how hefty an F/12 8" would be and what a mount it would need 

[Stu]

I agree! Peter Newise marketed the Cape Newise scopes a long time ago which seemed to be an attractive design but in practice had many production and quality issues from what I have read. I nearly bought one at the time but am glad I didn't in the end.

These Zerochromats sound like a variation of the same thing, and naturally quite complex so you would need to be sure that the quality and stability of the alignment is there I imagine.

They look great in theory.......

Stu

[Peter Drew]

I saw the 8" Zerochromat at Kelling a couple of years ago, unfortunately no chance for a look through. Despite its relatively light weight it still looked huge on an EQ6 and might have problems in windy conditions. I've made several long focus folded refractors including four 8", the folding mirrors are tricky to set up initially but if the mechanical design is adequate they seem to hold collimation well.