Weighted alt-az mount.

[Franklin]

Not very familiar with alt-az mounts, apart from my little porta, but I'm wondering if there's any info out there on balancing the scope in azimuth with weights. I'm aware that the azimuth balance does not have to be as critical and exact as when balancing a scope in RA with an equatorial mount but I'm trying to get it spot on so as not to put any extra stress on the motors. I've just received an APZ base for my Vixen AP mount and have been playing around with it today. With the FC100DC on board I've got the balance point in altitude when the scope is at 45 degrees but finding the balance in azimuth is not that straight forward. If I weigh the ota and place the same weight at the same distance down the counterweight shaft that the scope is from the centre of the azimuth axis should do it, I think. What are folk's thoughts on this? or am I just being over finicky? If it was purely manual it wouldn't really matter but as I intend using it with the motors I just wanted to do the correct thing.

 

[Alien 13]

Nice setup.

Apart from fitting strain gauges you could perhaps use one of them thin kitchen scales under each of the rear tripod legs in turn to check..

Alan 

[Roy Challen]

46 minutes ago, Franklin said:

Not very familiar with alt-az mounts, apart from my little porta, but I'm wondering if there's any info out there on balancing the scope in azimuth with weights. I'm aware that the azimuth balance does not have to be as critical and exact as when balancing a scope in RA with an equatorial mount but I'm trying to get it spot on so as not to put any extra stress on the motors. I've just received an APZ base for my Vixen AP mount and have been playing around with it today. With the FC100DC on board I've got the balance point in altitude when the scope is at 45 degrees but finding the balance in azimuth is not that straight forward. If I weigh the ota and place the same weight at the same distance down the counterweight shaft that the scope is from the centre of the azimuth axis should do it, I think. What are folk's thoughts on this? or am I just being over finicky? If it was purely manual it wouldn't really matter but as I intend using it with the motors I just wanted to do the correct thing.

 

I agree, nice set up. I think the way you're balancing is fine, that's what I do with my Mini AZ and Skymax 90.

I have a vixen polaris which I balance differently. I put that in EQ mode and balance it as normal. Then just undo the clamp for EQ and put it in AZ.

[Franklin]

23 minutes ago, Alien 13 said:

thin kitchen scales under each of the rear tripod legs in turn to check..

Never thought of that. Presumably each leg should weigh the same? Thanks.

[Franklin]

6 minutes ago, Roy Challen said:

I think the way you're balancing is fine

I hope so. When I put the same ota on an equatorial mount I would be using a further 2kg of weight to balance correctly.

[Franklin]

1 hour ago, Alien 13 said:

kitchen scales under each of the rear tripod legs

Genius. Had the scope end over a tripod leg and weighed, 5.1kg. Spun around 180deg so counterweight bar over the same leg, 4.7kg. Moved the 1.9kg weight to the end of the bar and bingo, 5.1kg. One nicely balanced scope, thanks @Alien 13.