10" Truss design for EQ Platform

[Astro78]

I'm considering building a light weight 10" or even 12" (if allowable) truss style newt for an Eq mount, say an EQ6. Losmanday being way too expensive.

The size and being able to get a better quality primary mirror are attractive. There seems to be a lot of unnecessary weight in the current 8" with the full steel tube and the heavy spider and primary mirror mounts etc.,

Any tips/advice?

[iceman (Mike)]

I think it has been discussed previously, but the truss design simply won't work on an EQ mount -though it's perfect for an EQ platform.

On an EQ mount, the scope needs to be held in the middle - something the truss design is simply not designed for.

You'd get bending and flopping and collimation would be a nightmare!

[Astro78]

I see your point. Could probably save a bit of weight by cutting oblique strips off the tube but that's about it....

[Karlsson]

Originally Posted by iceman

I think it has been discussed previously, but the truss design simply won't work on an EQ mount -though it's perfect for an EQ platform.

On an EQ mount, the scope needs to be held in the middle - something the truss design is simply not designed for.

You'd get bending and flopping and collimation would be a nightmare!

A possible solution may be a Serrurier truss design - see Steve Lee's page:

http://www.aao.gov.au/local/www/sl/sl-tels.html#ni-tel

...but I doubt if an EQ6 is suitable for this application.

[Astro78]

That looks heavy, here's another one - on the Eq6.. This one's 12.5" and for sale here on IIS

[CoombellKid]

Mike,

Why would the scope need to be held in the middle on an EQ mount?

I think the possibility of a truss design is quite feasable. Most truss dob
designs the balance point is at the top of the mirror box. Where there
is (or can be incorporated) sufficient strength to mount to an EQ mount.
However in saying that and from my experience with EQ mounts, it would
be a great wind catcher especially if shrouded.

regards,CS

[netwolf]

I recall reading that the Serrurier truss is designed to avoid flex, by duplicating the flex in the upper part of the OTA in the lower part.

Regards
Fahim

[Rob]

I came across these plans for a truss design that looks to be eq-mountable:

http://www.rfroyce.com/10f6tel/

I'd be interested in others' views on the design - I'm thinking of giving it a go!

Cheers,
Rob