ATM Components quality

I am planning to build a 12.5"/f6 Truss dob. I need to source the primary cell, secondary holder, secondary mirror, spider and the focuser. Novak are available in Australia and JMI focusers are also available, both are extremely expensive. Can someone give me the URL for these companies please as it may be cheaper for me to import direct into Australia. I have looked at the websites for Protostar and University Optics and they are under consideration. UO prices seem very reasonable, can someone please rate the quality of the components from UO, Novak and Protostar and advise of any advantages or disadvantages of these different suppliers' components. I will be using a premium grade primary so dont want to compromise the quality of the telescope but I am looking to save any money I can. I know that the JMI focusers are very good but they are very expensive in OZ, is there anything else thats good quality and a bit cheaper.

Thanks in advance.

Clear Skies
John Bambury

John,
I've had good luck with Astrosystems, Protostar, and Novak secondary holders and spiders. I especially like the Astrosystems four-point "tool-less" approach (thumbscrews) for collimation on 3.1" and larger holders, and like the Protostar clutch system. (I ended up making my own holder that combined features of both!).

Astrosystems also makes highly-regarded primary cells; I'd stay away from the UO one because their "nine point" suspension is actually nine rubber pads on three radial arms, vice floating triangles.

I've got a JMI DX1 on my 16" Dob, but if I were doing it over again I'd look seriously at a Starlight Feather Touch focuser. Get a two-speed model if you are planning to do much planetary observing.

Re secondary mirrors, the best deal I've found has been Antares Optics. (They're a sponsor here.) They test each of their pieces and send the Zygo interferometer print with each, and their prices are good to excellent, depending on size and availability from stock. I have a Pyrex 3.1" (1/15 wave, 1/100 RMS) and a fused quartz 2.14 (1/18 wave, 1/100 RMS), and both have performed up to their specs.

Jim

Regarding a focuser, I recently obtained a nice dual rate Crayford style focuser from Moonlite Telescope Accessories (www.focuser.com). Nice, smooth action, although not quite as nice as say a Featherlite. But at only $265.00 it's a bargain. I'm really happy with mine, fine focusing is a snap.