RC and balancing

[jaspalchadha]

Hi all

for members with 10 inch RCs scopes have you had any balancing issues and if so what tech have you used to resolve it.

Problem I am having is the DEC is perfect.

The RA is slightly East heavy.. However when I lock it to the home position( scope pointing up and counterweight facing ground ) and releasing the clutch the scope dips down to the west..

Any thoughts. Been a while since I done any balancing

[ollypenrice]

I don't think this has anything to do with which scope you are using.

In all probability your dynamic balance is a little out. From your post you are east heavy when the C/W bar is horizontal? But with the C/W bar is pointing downwards you are slightly west heavy? Then something on the west side of the scope, like the finder or guider or whatever, is pulling it west. This would mean that from an observer's point of view you have some extra weight on the right of the scope when the CWs are down. By the time the CW bar is horizontal that extra weight is now underneath the scope. If you balance it in RA in that position you have allowed for it. When you put the scope up and the weights down you haven't, because the imbalance is off to the right, not centred under the scope any more.

Olly

[jaspalchadha]

Ah ok.. perhaps this is little more useful http://www.dailymotion.com/video/x22m4w7_cem60-bal-part-2_webcam

[ollypenrice]

What's that telling us? I wasn't sure.

You've got a basic balance, more or less, right? If you just did this by sliding the OTA forwards and backwards and the weights up and down the shaft you would be in balance provided your scope was equally heavy on its right side and left side. It doesn't sound as if it is, which is not unusual, so that is the dimension you now have to balance. It's fairly easy;

Set the CW bar to horizontal and set the OTA to point at the zenith. Stand on the opposite side of the rig to the CWs so you are looking along the line of the shaft, though the OTA is blocking your view.

Release the Dec clutch and see if the OTA is happy to remain vertical. I don't think it will be. I expect it to fall to the right, so it needs more weight adding, somehow,  on the left. When you have balanced it this way the OTA should stay in any position you put it.

With the added weights yu'll now need to rebalance in RA using the counterweights.

Olly

[jaspalchadha]

Thanks olly ill give it a shot after work

[jaspalchadha]

Only btw it's not the ota it's the Dec that's not staying in anyway..

[Thalestris24]

Hi

I always follow Dion's excellent Youtube vid:

https://www.youtube.com/watch?v=hGduG2jB9ec

and his follow-up which explains and clarifies a few things (esp for imaging):

https://www.youtube.com/watch?v=uK2bXfVNoQU

Hth

Louise

[ollypenrice]

Only btw it's not the ota it's the Dec that's not staying in anyway..

I don't understand this. What do you mean by the Dec?

Olly

[nigelg]

Because I have two scopes setup I am using a dual side by side mount bar.

This allows me to slide the RC  North, South, East or West to achieve balance.

Nigel