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Balance


D4N

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I've read before about intentionally off-balancing the mount to ensure the gears stay meshed but I haven't spent any time trying this and just left thing neutral.

Tonight I was in a hurry when I opened up the obsy and I forgot to extend my counterweight shaft, that meant the mount was very East heavy.

The guiding was really good so I only realised when I went to close up the obsy and found the counter weight bar already retracted.

With the position of my target I guess this was putting more weight on the RA motor than I would like but I may consider paying more attention to balance now.

I'd be interested to know if others do this a lot and what they do about flips? Just leave it so it becomes West heavy or go and adjust it?

/Dan

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I have an obvious east heavy unbalance, the weight falls back easiiy, not just slowly.

This I found did make a big difference by keeping the mesh solid.

I don't at the moment image past the meridian but I need to find the position of the weight

for that so I can in the future.

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I have an obvious east heavy unbalance, the weight falls back easiiy, not just slowly.

This I found did make a big difference by keeping the mesh solid.

I don't at the moment image past the meridian but I need to find the position of the weight

for that so I can in the future.

I find that a heavier east side helps with the RA guiding too.

Also I suspect that a deliberate imbalance in declination coupled with a deliberate azimuth error in PA will have a similar beneficial effect in dec. guiding. I haven't quite worked out how to deliberately set this up yet, but as I have a permanent pier I can get repeatability in my experiments. Of course this will only work for one side of the pier, but havng a pier means that it is possible to go a long way (all the way for targets below 45 deg declination!) past the meridian without needing a flip. It is also possible to go quite a bit past the meridian on a tripod :)

I've read before about intentionally off-balancing the mount to ensure the gears stay meshed but I haven't spent any time trying this and just left thing neutral.

Tonight I was in a hurry when I opened up the obsy and I forgot to extend my counterweight shaft, that meant the mount was very East heavy.

The guiding was really good so I only realised when I went to close up the obsy and found the counter weight bar already retracted.

With the position of my target I guess this was putting more weight on the RA motor than I would like but I may consider paying more attention to balance now.

I'd be interested to know if others do this a lot and what they do about flips? Just leave it so it becomes West heavy or go and adjust it?

/Dan

Sent from my iPad using Tapatalk

Out of interest, why do you move your counterweight bar if you have an Obsy?

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East heavy is often good for worm and wheel mounts. It keeps them pushing against the resistance rather than letting the payload fall acorss backlash to the other side and be bounced back again by the guider ad infinitum.

In Dec, Paul's point about a delibarate slight PA offset needs to be combined with not activating Dec guiding corrections in both directions. You need to activate the Dec in only the direction needed to correct the slight PA error. This avoids, once again, the problem of the guider shooting the payload endlessly back and forth across the backlash.

My most-used mounts are a Mesu roller drive and an Avalon belt drive. No backlash...

Olly

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Thanks for the replies, that all makes sense.

My obsy is tiny, it is easier to retract the counterweight bar than work the mount into a position so I can close it.

I can see it would be fairly easy to create a small azimuth error in the PA if you drift align, just leave a slight drift on that axis. Probably a lot harder with other alignment methods.

I would love some mounts like that Olly, I don't think I could swing it by the SWMBO accountancy department so soon after buying a CCD though!

/Dan

Sent from my iPad using Tapatalk

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Thanks for the replies, that all makes sense.

My obsy is tiny, it is easier to retract the counterweight bar than work the mount into a position so I can close it.

I can see it would be fairly easy to create a small azimuth error in the PA if you drift align, just leave a slight drift on that axis. Probably a lot harder with other alignment methods.

I would love some mounts like that Olly, I don't think I could swing it by the SWMBO accountancy department so soon after buying a CCD though!

/Dan

Sent from my iPad using Tapatalk

Same here, my obsy is quite small but luckily with just dslr and lenses onboard the weight bar is a fair way in.

Have my eye on a Mesu or Avalon, may be this coming year, depends if and when I get back money I'm owed

from my work and a sell off I keep intending to do.

Not in to much of a hurry as the HEQ5 does a surprisingly good job if tweaked a bit.

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