balancing ota

[Thruxton]

At the moment my OTA is held in a yoke/clamp/(what's the correct term? ) which is roughly halfway along the tube (Newtonian) but I wonder if I ought to move it. In its current configuration, the OTA is bottom-heavy and the previous owner had fastened a weight to the top of the tube to balance it.

It occurred to me that it might be better with the yoke (etc. . .) closer to the mirror so the top weight could be done away with or reduced in size.

Am I failing to realise something blindingly obvious? I can't see any reason to hang extra weights all over the place, and the only side-effect I can anticipate if I move the yoke is that the eyepiece will be just that little bit further off the ground.

I am as yet making no allowance for the weight of any eyepiece, and anyway the ones I have are not particularly heavy.

[jgs001]

I balance my scopes by moving them in the tube rings... it's probably the easiest way to do so... So, I'd say yes.

What scope is it you have, perhaps someone can offer some specific advice for you... I've not used a newt, so can't I'm afraid.

[Thruxton]

Can't give a manufacturer's name because the telescope was made by the guy I bought it from. I've emailed him for advice but as yet no reply, and anyway extra opinions are always valuable.

I'm very much a beginner with 'proper' scopes, after putting up with some pretty awful optics on a cheap one I used to have. I must confess (holds head in shame) to having tried this one out indoors just to see how it works - looking at Saturn through tree branches and double glazing. Hardly ideal but a far better image than I had previously obtained!! Obviously some potential here.

My other 'bright' idea is to use a smaller counterweight on a longer bar in an attempt to reduce the overall wight the mount has to cope with. Before I rush off to the workshop, is this a reasonable idea? I suppose it might foul tripod legs, or just get tripped over in the dark.

[Thruxton]

Can't give a manufacturer's name because the telescope was made by the guy I bought it from. I've emailed him for advice but as yet no reply, and anyway extra opinions are always valuable.

I'm very much a beginner with 'proper' scopes, after putting up with some pretty awful optics on a cheap one I used to have. I must confess (holds head in shame) to having tried this one out indoors just to see how it works - looking at Saturn through tree branches and double glazing. Hardly ideal but a far better image than I had previously obtained!! Obviously some potential here.

My other 'bright' idea is to use a smaller counterweight on a longer bar in an attempt to reduce the overall wight the mount has to cope with. Before I rush off to the workshop, is this a reasonable idea? I suppose it might foul tripod legs, or just get tripped over in the dark.

[stev74]

Hi Thruxton,

I'm assuming that you have an equatorial mount (EQ) - so you need to balance it on both axis.

To balance in declination (DEC) you need to either loosen the mounting rings and slide the tube back and forth in the rings or slide the dovetail bar (possibly what your calling a yoke) back and forth in the mounting plate.

For the Right Ascension axis (RA) you need to move the weights along the counterweight bar. If you get to the end of the bar you could buy or make an longer (extension) bar to help balance the set up.

I hope that all makes sense, there is a really good section on balancing you mount on this web page - Setting Up an Equatorial Mount - McWiki which might give you a better idea. There is also lots of other info for EQ mount owners and it was a real help when I was starting out.

Cheers

[Thruxton]

Thanks for the McWiki reference, Steve. I'll have a look at it.

BTW, the 'yoke' I'm referring to is not the dovetail, it is the big clamp which goes round the OTA. In my case it is a solidly-made wooden design, and moving it up and down the OTA to balance it will require a few mods. Nothing too difficult.

I'll just refer to it in future as a clamp and hope others understand which bit I'm going on about.

BW

Richard