Octopus, technique or 2 man job

[acme]

Hi,

I am struggling to attach my Orion Optics 250mm onto the Vixen GP mount, the scope is quite light and it’s the short tube version so weight is not the issue. I just find it so difficult to line up the dovetail, manoeuvre it into place then tighten up the screw without the mount moving all over the place.

Am I doing something wrong? Apart from building an obsy or buying a dob base for the thing..Think I need a 5 inch APO.

Acme

[John]

I have the same scope and I agree it can be a struggle to get the dovtail bar into the dovetail on the mount and tightened up. I usually make sure that the mount is positioned so that I can hold the tube horizontally then you can cradle the tube with both arms to start with, get the dovetail bar into the dovetail then reach round with one hand to tighten the 2 knobs.

I also have 5" and 6" refractors and the issue is more or less the same as they weigh almost as much as the 10" and the tubes are a bit longer.

A conventional dobsonian mount is easier in this respect because you just drop (not literally !) the scope onto the altitude bearings. Simples !

[johninderby]

You might want to consider fitting one of the ADM dovetail saddles to your mount. Just fasten a short dovetail bar (the SkyWatcher short dovetail) to the bottom of the ADM saddle and put that permanently on your mount.

http://www.firstlightoptics.com/proddetail.php?prod=adm_vixen_style_saddle

The ADM saddle is just so much more precisely made that the dovetail bar on your OTA will just drop into it and has nice big knobs to tighten it with. It makes what can sometimes be a really fiddly job very easy. Also as it clamps the full length of the saddle it holds the OTA more securely (doesn't mark up your dovetail bar as well) and moving the OTA to balance it is also a lot easier.

John

[brianb]

You might want to consider fitting one of the ADM dovetail saddles to your mount.

That is probably the best solution. I have enough problems getting my FLT 110 into the saddle from the end, I can't imagine how I could manage to do the job on my own with a much bulkier, heavier tube assembly.