How critical is eq balancing?

[Coastliner]

Hi All,

I am going to attach a rotator ring to my 150p OTA (probably an embroidery hoop to start off with), but, after watching Dion Heap's Astronomyshed video I understand that the balance will be thrown as the tube rotates.

Is this imbalance enough to cause damage to the mount drive gears? I accept the fact that it may throw tracking out, but I would only rotate the tube for observing rather than AP. How far out can the balance be before damage is done to the EQ mount?

Thanks,

Neil.

[Tinker1947]

If you viewing then it won't matter, if you were imagine DSO's then the DSLR/CCD would normally end up underneath to get the balance right......

[MarsG76]

Even when observing the stress on motors will increase in a unbalanced EQ head. Also while observing you will slew more frequently. I'd say if you want your gears and motors to last to have your mount as close to balanced as possible with a bit of eastern bias to counter backlash.

[brantuk]

It's always best to have the rig properly balanced - to avoid stressing motors and gears - and to make it easier to move the OTA around without the scope nosediving into the mount at either end. But turning the tube in hoops isn't going to throw the balance out enormously unless you're using heavy eyepieces.

Just be careful when you loosen the clutches and always have a firm hold on the tube with your other hand. Alternatively tweak the balance by sliding a counterweight up or down the bar - or slide the scope up/down in the mount shoe - saves a lot of worry in the dark.

For imaging though it's essential to have the lot accurately balanced.

[Coastliner]

Thanks all,

I accept that balancing is essential, what I'm asking is how much tolerance do I have? if the tube is rotated will it cause so much of an imbalance that the gears will strip? Do people rotate without altering the position of the counterweights?

In my head I now have the impossible thoughts of some kind of pulley arrangement that alters the counterweight position as the tube is rotated!

[Wazzat]

Hello Neil,

I was wondering if you could balance the tube itself, so that if it is turned, the weight of it stays in the same place. Maybe a weight equal to the focusser and a usual eyepiece, positioned on the opposite side of the tube. And another one opposite the finderscope or Telrad etc.

Never heard of this being done, just thinking aloud really, seems simpler than pulleys!

Good luck.

[Tinker1947]

Have you ever heard of the gears stripping through a scope being unbalanced, the short answer is " No " you're worrying about nothing just get it close for viewing, that all you need to do...

[Coastliner]

Have you ever heard of the gears stripping through a scope being unbalanced, the short answer is " No " you're worrying about nothing just get it close for viewing, that all you need to do...

That's exactly the answer I was looking for. I know that it would not be a good idea to slew the mount around with all the counterweights on and no OTA as one extreme, I just needed reassurance that the imbalance caused by rotation would not be enough to cause damage.

Cheers all!!

[Scott]

I think....No, I'm certain that for visual, you only need worry about balance in two axis. the amount the balance changes by rotating the scope is minimal and will not worry your set-up. balance in the third axis would be  madness for visual. for imaging, definately go for the 3 axis balance . 

I think Dion has caught many people out by not stating that the 3 axis balance is only for imaging. shame really coz most of his vids are quite helpful 

[Coastliner]

Thanks auspom.