Piggyback mounting.

[alexjj67]

I am trying to mount these scopes together ED80 for Imaging, ST80 for guiding.

Can any one think of a reason why this would't work, obviously with 2 sets of rings. 

Or would it be better with a bar Between the scopes.

Or side by side mounting with a ADM dual system.

This might be a stupid question but how do you attach the ADM side by side system to a mount (Celestron AVX)

[IanL]

I use two tube rings on the ED80 which doesn't have a foot so it needs them anyway. Then a long dovetail bar attached to the top using the camera screw holes in each tube ring. Then another pair of tube rings attached to the dovetail with a different hole spacing for the ST80.

The main problem is that the camera screw holes usually have a lip around them which makes it hard to get the long dovetail bar stable. You could grind them flat or use two pairs of CNC tube rings instead which have flat top and bottom surfaces that mate better. They are expensive though and hard to find the right size for the ED80.

What I did was put long screws through the cone error adjustment screw holes in the long dovetail. These bear down on the focuser body and the front cell of the ED80 and keep everything rock solid. You could use a flat steel bar and drill the necessary holes if you don't have a suitable dovetail.

Avoid using guide scope rings if you can. The guider and the imager don't have to be closely aligned at these focal lengths and tube rings add yet more flex.

[DaveS]

I use one of these

http://www.firstlightoptics.com/adm-vixen-type-v-series/adm-v-series-side-by-side-mounting-system.html

With my Meg 90 on one side and the ST80 on the other. I also replaced the original Skywatcher puck with the ADM version

http://www.firstlightoptics.com/adm-replacement-saddles/adm-dual-saddle-upgrade-for-heq5-and-eq6-series-mounts.html

They do a version for the AVX.

I simply rotate the sadle through 90 deg so that it's running side-to-side when the 'scope is pointing at Polaris.

[alexjj67]

I use one of these

http://www.firstlightoptics.com/adm-vixen-type-v-series/adm-v-series-side-by-side-mounting-system.html

With my Meg 90 on one side and the ST80 on the other. I also replaced the original Skywatcher puck with the ADM version

http://www.firstlightoptics.com/adm-replacement-saddles/adm-dual-saddle-upgrade-for-heq5-and-eq6-series-mounts.html

They do a version for the AVX.

I simply rotate the sadle through 90 deg so that it's running side-to-side when the 'scope is pointing at Polaris.

I thought that might be the case but I thought it couldn't be that simple. 

[Astroboffin]

I am trying to mount these scopes together ED80 for Imaging, ST80 for guiding.

Can any one think of a reason why this would't work, obviously with 2 sets of rings. 

Or would it be better with a bar Between the scopes.

Or side by side mounting with a ADM dual system.

This might be a stupid question but how do you attach the ADM side by side system to a mount (Celestron AVX)

I think that the set up in your images above will work fine , as long as the tube clamps are nice and tight, you shouldn't get and flexure either.

AB

[MattJenko]

Single point of contact seems a little risky to me. I use a dovetail inbetween and bolt it to the main scope rings and then bolt the ST80 directly to it via the shoe connector it had in 2 places:

[Astroboffin]

Single point of contact seems a little risky to me. I use a dovetail inbetween and bolt it to the main scope rings and then bolt the ST80 directly to it via the shoe connector it had in 2 places:

Single point of contact seems a little risky to me. I use a dovetail inbetween and bolt it to the main scope rings and then bolt the ST80 directly to it via the shoe connector it had in 2 places:

I think the OP says there will be two pints of contact, as he will be using two sets of rings, I think the one set in the picture is just to show how he will do it, before purchasing another set

Regards

AB

[alexjj67]

I think the OP says there will be two pints of contact, as he will be using two sets of rings, I think the one set in the picture is just to show how he will do it, before purchasing another set

Regards

AB

Yep I was planning to use 4 rings in total.

[alexjj67]

Yep I was planning to use 4 rings in total.

But I think I will remove the mount plate off the ED and replace it with a bar across the both rings.

I think that would be a more solid connecting with the mount.

I don't like the idea the weight of both scopes will be connected to the mount all on the back end of one scope.  

[Astroboffin]

But I think I will remove the mount plate off the ED and replace it with a bar across the both rings.

I think that would be a more solid connecting with the mount.

I don't like the idea the weight of both scopes will be connected to the mount all on the back end of one scope.

Yes that sounds even better, and even more solid

AB