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g__day
05-08-2013, 11:49 PM
Second question for the night - what's the best way to align two side by side OTAs?

I am trying to optically align my WO FLT110 OTA with my C9.25. These scopes sit side by side on Losmandy saddle bars. Another smaller OTA sits on the 110 - but that is simple to adjust - it sits in Losmandy O rings (see below).

The C9.25 connects right into the bar - the FLT sits in mounting brackets like http://www.iceinspace.com.au/forum/attachment_browse.php?a=144806

The centre of the FLT light path is about 3-5 arc minutes low on the SCT - what is the best way to raise it? Should I just cut some extra felt and use it at the bottom of one of the two brackets to try and raise the rear end of my FLT the required amount?

Many thanks,

Matthew

PS

I guess the alternate (very time consuming way is to slowly shim the bottom of one of the two brackets holding the FLT, until everything matches) but given I would have to take it all apart multiple times and paint the shimmed bottom - that would be a long process I would rather avoid!

mithrandir
06-08-2013, 10:20 AM
Matt, if he still has any you could consider a Robin Casady TGAD (http://www.robincasady.com/Astro/TGAD.html)

Big bikkies but well engineered. The WO should not be too much for it.

g__day
06-08-2013, 10:30 AM
Yes I'd love the Cassidy plates - but seeing that I am only 3-5 arc minutes low (left / right alignment is fine), and seeing that I am carrying 3 OTAs + focusers and imaging gear - the Atlux is probably at the point where the extra kgs won't be kind to it!

I am super pleased by how well my mount is performing nowadays, I just need to nudge my second OTA a tiny bit. Will adding 1-2 layers of say 2cm * 5 cm felt under my second OTA then tightening the rear bracket simply give me most of what I want any way?

Cheers,

Matthew

PS

Well I've added the felt where I think its needed - will find out tonight if it has helped or hindered!

Joshua Bunn
06-08-2013, 03:42 PM
I would recommend some shimstock between the brackets. loosen the bolts then slide in some shims then tighten, trial and error. I wouldnt have thought youd have to dismantle everything?

Josh

Lee
06-08-2013, 03:54 PM
I'd be inclined to use something non-compressible to shim... aluminium/steel/HDPE plastic etc.....

g__day
06-08-2013, 08:33 PM
Seems a bit better - though now of course the clouds have all rolled in!