Belt Modded HEQ5 - East Heavy or not?

[smr]

Hi,

I'm trying to look for a definitive answer to this but haven't found one, I've read two conflicting bits of advice where it says if the belt mod (rowan belt mod from rvo) has been done then there is no need for east heavy balancing and that perfect balancing must be done, but then I also read that even with the mod it should be slightly east heavy. Which is it ?

[spillage]

With my belt mod I always make sure it's perfectly balanced.

[vlaiv]

+1 full balance

[smr]

Thanks guys. 

[FLO]

The mount should be balanced, though 'perfect' balance is not necessary and might even be undesirable. 

HTH, 

Steve 

[david_taurus83]

My AZEQ6 is generally unbalanced most of the time. Ever so slightly. No issues. There's always that bit of backlash.

[James]

Belt modding removes one of the main sources of backlash but there are still parts within the mount where backlash is possible so I've assumed it's best to get close to balance but not stress too much about it. I've stopped deliberately moving my counterweight out (east) or in (west) though as that doesn't seem to be necessary now  

[spillage]

I must admit that I took the clutches off my mount last night just to check the newly installed dew bands were doing their job (working nicely) and the dec was slightly unbalanced. I still managed around .60-.70 most of the night.  I guess this was just the extra weight from the heaters and cables which have not been properly routed yet.

[Paul and Chrissy]

Hi.

l use an alternative to balancing east heavy. Every time you have to do a meridian flip, you have to readjust your counterbalance weight, which can be a pain to get exact. What I do is balance as neutral as possible and then add a weight on a pulley. See  image below. The advantage, is that the pressure is always the same even when you flip to the other side of the mount. The gears will always be in constant mesh. Just another way of doing it.

[vlaiv]

11 minutes ago, Paul and Chrissy said:

Hi.

l use an alternative to balancing east heavy. Every time you have to do a meridian flip, you have to readjust your counterbalance weight, which can be a pain to get exact. What I do is balance as neutral as possible and then add a weight on a pulley. See  image below. The advantage, is that the pressure is always the same even when you flip to the other side of the mount. The gears will always be in constant mesh. Just another way of doing it.

Why do you need to do such thing on CEM60?

As far as I know it's got magnetic tension on worm - this should enable constant engagement and minimize backlash.

[Paul and Chrissy]

It does have magnetic tension, but my guiding is more consistent when the weight is in place. All gearing assemblies will still have play, not just in the meshing of the gears. The fact that the worm/motor unit moves in and out to engage/disengage will inherently have tolerance to move. If you can keep a controllable consistent pressure on the driven side of the gears it will run smoother and have less flex in the gearing unit as a whole. I don’t get so much variation in guiding when I have to flip to the other side of the mount.  I suppose the bottom line is l like modifying things to make then run to their optimum. 

[vlaiv]

3 hours ago, Paul and Chrissy said:

It does have magnetic tension, but my guiding is more consistent when the weight is in place. All gearing assemblies will still have play, not just in the meshing of the gears. The fact that the worm/motor unit moves in and out to engage/disengage will inherently have tolerance to move. If you can keep a controllable consistent pressure on the driven side of the gears it will run smoother and have less flex in the gearing unit as a whole. I don’t get so much variation in guiding when I have to flip to the other side of the mount.  I suppose the bottom line is l like modifying things to make then run to their optimum. 

I've seen others report that critical balance is very important with this mount for best results, so this intrigued me.

[FLO]

On 30/01/2019 at 17:27, FLO said:

The mount should be balanced, though 'perfect' balance is not necessary and might even be undesirable. 

 

3 hours ago, Paul and Chrissy said:

If you can keep a controllable consistent pressure on the driven side of the gears it will run smoother and have less flex in the gearing unit as a whole. 

What he / she said ^ ? 

Steve 

[vlaiv]

1 minute ago, FLO said:

 

What he said ^ ? 

Steve 

I think we are talking about two different mounts here? Heq5 and CEM60, both different performance and mechanical layout?

[FLO]

Good point. I was referring to the OP's original question regarding his HEQ5 Pro. I am not familiar with the CEM60, though Paul & Chrissy's observation suggest the same might apply. 

For most traditional mounts they work best if not 'perfectly' balanced. So the motors and gear's have something (only a little) to push against. 

HTH,

Steve 

[barkis]

With the OTA  on the East side of an equatorial mount, It's weight should be slightly 
more than the counterweights. On the West side, the opposite applies. The C/W's should slightly outweigh  The OTA.
Ron.

[Paul and Chrissy]

The original comments were about the HEQ5. I should think using my little pulley and weight mod would work really well on an HEQ5. Balance it as close as you can first, and then slip the weight on. No need to worry about what side of the mount you are on, or. meridian flips. You can add or remove washers to give the amount of bias you want.

[FaDG]

Not a scientific answer on my side,  just return from Experience. 

Before and just after belt modding my HEQ5 I carefully checked slight East imbalance: as I use a newton The camera weight shifts according to pointing. 

But this meant releasing the clutches and need to perform a 3 star alignment each time. 

At a certain time it was too much and marked the position on the counterweight bar that gave "good enough balance". 

This i use regardless of pointing and always have seeing-limited guiding, achieving well under 1arcsec on good nights, with top performance of 0.38-0.40 every once in a while. 

And for me this is enough! Would be interested anyway in a less-practical and more rational solution. 

Fabio