Balance Questions

[Spotty Albino]

Hi all, this is my first post on these forums

I own a reflector telescope on an equitorial mount, and I have a question about the way it is balanced. When using the scope one of the control cables (the one controlling up and down movement) is easily turned, to make the image in the lens move smoothly across the sky, whilst the other control cable (the one controlling roll), does not twist smoothly and jerks the image, and makes the scope shake.

I tried loosening the axis of movement that this cable controls, but that simply causes the gravity to take hold and for the scope to sag towards the ground, and the control cable no longer has any effect on that axis.

How can I rig it so that twisting both control cables reults in a smooth movement? Is it that I don't have enough weight to balanced the scope so I can loosen the axis enough for smooth movement? And if so how can I add more weight

Thanks
Albino

[ballaratdragons (Ken)]

Hi Albino, (alias Spotty), welcome.

It does sound like it isn't balanced. What scope is it? Make? Size?

Any pics of it? We might be able to spot a problem.

[[1ponders] (Paul)]

A pic wouuld be great SA

[ving (David)]

got counterweights? you need to move them down...losen off your RA axis till the scope just ants to drop all the time then move the weights down till the scope nolonger wants to drop.

[Spotty Albino]

As you can see in the photos I've got a counterweight, and it's as far as it will go. Maybe I need another?

http://img.photobucket.com/albums/v6...telescope3.jpg

This is how I normally have the telescope set up. /\
http://img.photobucket.com/albums/v6...telescope2.jpg
The stiff cable is shown. /\
http://img.photobucket.com/albums/v6...telescope1.jpg

Contact point between cable and axis. If I loosen that tabe the telescope sags in the opposite direction to the counter weight. /\

Thx
Cya
Albino

[33South (Chris)]

Originally Posted by Spotty Albino

Maybe I need another?

Yep thats the answer. To check the weight you need move the weight to no more than half the length of the bar then hang off a bucket a fill it with sand/water/scap iron until it balances. Weigh it then of to Rebel sports.

[Spotty Albino]

How much is another weight likely to cost in AU? Also, where can I get them? Not sure if I've got a Rebel Sports store near me.

K Thx
Albino

[RAJAH235]

Also might be an idea to 'centre the tube'. Looks a tad too far forward.
Ideally should balance in both axes with 'no locks on'. 33South has the solution.
L.
ps. Adjust for as near to zero play in the drives/cables.
pps. Any sports store will/should have weight lifting equipment. Just take your counterweight with you for hole size. Not sure of cost, maybe $10/$20??? Could use lead weight off a divers belt.

[ving (David)]

any sports store that sell weights for weight lifting will do. I dont know how heavy you need or what you have so I dont know what you should get tho.... try a couple of 2.5kg wieghts? I use 4 X 2.5kg with my 200x1200 OTA.

[Spotty Albino]

Ok, thanks everyone, that really helps. Hopefully now I should be able to pan the scope around the sky with a lot less shaking! I'll head off to a sports stuff at my next opportunity.

Happy