scope balancing problems

[blueskies123_89]

Hi all,

ok basically, I'm having trouble balancing the DEC axis with the setup. It's a newtonian, an ED80, and a DSLR.

The weight of the dslr hanging off the focuser is causing me troubles: It can be perfectly balanced when the tube is pointing East-West, but when it points South, the whole thing swings towards the camera facing side (with RA locked). My less than elegant solution, which hasn't worked, was to stick water bottles to the opposite side of the tube, right now it just seems like added weight that isn't doing much.

This is such a common setup that someone must've had a similiar problem that they solved, so help would be appreciated. Photos are attached so you know what I mean.

Thx
George

[jjjnettie]

You can't move the OTA further forward? You might have to invest in a longer dovetail bar.

[[1ponders]]

Hmmmm....sounds like the perfect job for rotating rings. Maybe when you get to where you want to image you can loosen off the rings and rotate the tube until it's balanced. Not having a newt I'm not sure how practical this is.

[Lismore Bloke]

It might be a good idea to weigh the camera and fittings, then attach that much weight on the opposite side of the tube, towards the mirror end, where you have the bottle. Speaker magnets that stick to the tube are often used, as they can be positioned to suit. Some use sand in a bag. The tube will have to be re-balanced in the cradle. The counterweight obviously would then have to be dropped a bit on the dec shaft to re-balance, with locks off.

[blueskies123_89]

I tried that... it seemed to make it worse, as the weight distribution shifts forward further to where the camera is.


Havn't thought of that option...


So do you mean that I havn't got enough weights on that? I will try more weights, but that would mean that the mount would hav to carry more... At least the positionw here the bottles are now is correct...?

Thx guys

[jjjnettie]

Good luck with it George.
Let us know how it works out.

[gbeal]

Cripes, you Ozzies must have a dry spot, you have to carry water bottles with you like that, LOL.
George.
Look at the picture you posted. You have a heap of weight out to one side, and while the water balance is helpful, why not just loosen the rings and rotate the tube, until you have something like the finder out to one side, and the focuser with DSLR out the other (looking end on). I actually have the focuser pointing straight down, "towards the mount/ground" in your picture. While it may not be the exact correct term, what I am suggesting is "radial balance". Try that.
Gary

[rat156]

George, your centre of gravity for the scope/camera setup is not on the axis of rotation of the Dec axis. The scope looks nose heavy, shift it back until it's balanced.

Cheers
Stuart

[blueskies123_89]

AHHHHH TOWARDS THE GROUND!!! it works!!! and i lost the bottles as well. I'm hitting myself very hard for not thinking of that now!

Thx guys! gee this forum does respond soo fast!

thx to everyone who has helped.

George

[blueskies123_89]

LOLL
Oh and yeah about that water shortage... its rained everyday for the last week or so here, not a single patch of clear sky -_-

[White Rabbit]

get your self a side by side set up it's far easier to balance. You could pick up on from bintel for less than $100.