20" strut Dob

Hi Folks,
One of our lads is thinking of going BIG ie a 20" strut Dob,I should be fairly ok re the construction but any tips and advice about pitfalls would be appreciated.
I would also appreciate any personal recommendations re suppliers of big mirrors.
Was I dreaming or did I see something at the WSP re a new flexible or thin mirror for big dobs?If so enlighten me. :idea:
I dont belive in favouritism but those who help will be allowed play with this

Oldham Optical in the UK make this size of mirror.
www.oldham-optical.co.uk/
I'd be very interested to hear how you plan to go about it. I was seriously considering getting one earlier in the year but plans changed slightly for a number of reasons (moved house and changed job). However, I do fully intend in getting one. It's only a matter of when rather than if. I'm thinking I might wait for the SSIA to mature first. The 19.5" 1/10th wave will cost Stg£2,300 plus shipping.

The information you saw on the flexible mirror you saw at Birr is something Eamon Ansbro is currently developing (or should that be "has developed"?). Perhaps you could send a pm or mabey he might reply to this thread. From my basic undrstanding of it, it involves a technology where the struture of the mirror is composed of a flexible membrane. The shape of the membrane is controlled by a pressure unit which reduces the air pressure behind the mirror to sort of "suck" it into the pressure cell thus creating the parabolic shape. Adjusting the pressure can increas or decrease the focal ratio from what I understand. Sounds like a very clever design.
Have I got that correct Eamon??

Michael

Michael ,
Checked out site -excellent - had heard about the "black" glass now I know it comes from Canada I'll look into it (no pun intended)as I have a few contacts there.
Eugene

If you do find dealers in Canada you specialise in large mirrors, let me know!
Thanks!
Michael

EUREKA !!! :lol:
Michael
I've found the suppliers to Oldham optical!!
Theyre ASM Products in Canada-Ontario,they make the BVC black glass and wait for it they just happen to supply all the parts to self build your own telescope at a very good price and their mirrors are 1/12 wave they sell mirror cells as well as beirings and focussers ,check them out on this site:- pages.infinit.net/asmprod/
Happy Surfing
Eugene

Excellent!! Good detective work Eugene!!
Prices are v. good. Well worth looking into a bit more.

Michael