A really basic piggy back question

[swag72]

This is a really basic question and one that I think I should know the answer to, but I don't!

I have got my new scope and some nice dovetails as I wanted to piggy back the smaller refractor onto the SW 120ED. So ........... how on earth do I do it?!!

I have got scope rings for both scopes, so I have the screws sticking up from the SW 120. Then I can get the dovetail for the smaller scope on these, but have no way to hold them in place. The dovetail screws into the scope rings of the new scope, so I have 2 scopes both with rings and dovetails on the bottom, but I can't join them up!!

The dovetail doesn't have threaded holes, so the screws go straight through.

[martin_h]

Cant you fix the dovetail onto the top of the rings of the 120, then fix the smaller scopes rings onto that, doing away with the shorter dovetail?

[Merlin66]

Sara,

martin's got the right idea...

The top screws on the rings are 1/4"W

You can drill a couple of extra 1/4 holes in the dovetail near the ends and use a 1/4 nut to secure the dovetail in place.

Then drill a couple of 6mm holes at the spacing to suit the smaller scopes and mount the rings as normal on the top of the dovetail.

[swag72]

Cheers both - Makes perfect sense - But, having tried it, I just wouldn't be able to fit the camera in the piggy backed scope if I did it. I guess most use piggy backing for guiding (and small camera) and not the complete imaging kit and filter wheel.

You learn something new each day! Got nice blue dovetails on now though!

[martin_h]

More expence...side by side mounting of the scope and guider?

[swag72]

I've already got a side by side bar, but wanted to piggyback instead. The other difficulty is that if I did piggyback, not only would the camera and filter wheel not fit, but the finder and guider scope that are on the 120ED were all in the way.

Damn hobby - it is so frustrating and difficult at times

[Gina]

Don't I know it, Sara!!! You get one thing right and something else goes wrong!

[Jessun]

How come you are so keen on piggybacking Sara? Are there any benefits?

A side by side seems more stable to me and it keeps the torque down for the same weight = happy mount :-)

[swag72]

I thought that a piggyback was more stable than a side by side and less prone to wind etc. Also, I could remove the weight of the side by side bar, as I think I must be very near to the maximum of my mount, if not over it!

[Jessun]

I wonder if it's not better to keep it as 'tight' as possible, especially close to the max of a mount. It's the torque that's the real killer and a side by side should reduce this despite the slightly bigger bar required. As to wind... hmm depends on where the this is aiming, luck of the day. I have a geoptic side by side bar which is really light wheight, low profile and takes vixen dovetails as it is.

[swag72]

Side by side it is as there is no alternative!!