EQ Mount Balancing After Belt Mod?

[glend]

Recently installed the Rowan Engineering Belt Mod on my NEQ6 Pro. Net research on balancing post the belt mod reveal differing opinions:
1. Balance neutral now as the belts don't allow the slop that the gears used to.
2. Balance east heavy as before because the worm shaft and gear still have slop in them - even if you have adjusted to remove backlash in this.

I have done some imaging test runs with the mount east heavy as before and things are fine, my guide graphs are nice and flat now. But is this no longer necessary?

What's to G O guys?

[codemonkey]

Hey Glen,

You'll likely need a slight imbalance as per usual. A lot of the backlash comes from the worm meshing which is still present.

As always, I'd advocate trying for yourself though.

Cheers,
Lee

[The_bluester]

I would think that would be correct, the worm will have an amount of end float in its bearing and a certain amount of backlash to the ring gear, slightly unbalanced should keep that lot all in tension. Just the amount of backlash has to be a lot smaller as there is simply less mechanism between motor and Axis. Less parts, less lash.

[AlexN]

Yep, imbalance as per usual, the belts actually do nothing with regard to the reason you need that imbalance.. The imbalance we induce is to keep the worm in solid contact with the worm gear. The belts do not modify that at all, backlash caused by imperfect spur gear meshing is completely removed and tangible PE improvements can be had on account of the lack of spur gear face contact with rough edges etc. However the real kicker for perfect performance is very clean gears with a film like application of the right grease and we'll adjusted worm meshing. Only after those things are under control would I look into the belt mod.

My Heq5 pro with a few new bearings, good application of grease and a few hours spent on the meshing now runs 2 to 3 minute unguided exposures with a quick polar alignment and about 6kgs on its back. I have no doubt with guiding and my current setup 30 minute subs would be possible.

[Camelopardalis]

Interesting. I did the belt mod last year and I always aim for balance. My guide graph is nothing special, but I'd wondered if that was because I haven't employed any form of PEC and I've been experimenting with drift alignment using the DARV method to speed up my setup. I typically get seeming random movement +/- 1" according to PHD.

I might set a little imbalance in the mount tonight and see if that improves. I often see it pulse east and then pulse west shortly after. Maybe my mount needs an expert tune up :shrug:

[AlexN]

Make sure you are east side heavy Dunk. That ensures that your mount is pulling the weight upwards rather than pushing it down. That gets you the best result.

[Camelopardalis]

Will give it a try, thanks :thumbsup:

When I was watching status bar it seemed to be making more RA pulses and the odd occasional Dec pulse.

Btw, how much imbalance are we talking about? (Apologies to Glen for the hijack!)

[jenchris]

It always helps to keep the meshing on one side.
I've an idea that the amount of weight can now be quite small though.
I have an idea my bearings are pretty tight and nearly obviate the need.
I've never touched any adjustments on my Neq6P and it seems to be quite neat on the phd graph.
simple drift align and never touhed it again - just turn it on and go.

[codemonkey]

Hmm, I'm not sure you've configured PHD properly there... if I'm reading correctly that says 0.12" RMS which I'm fairly confident is outside the realms of possible with a NEQ6 Pro... If I could consistently get that I'd never consider buying another mount.

[AlexN]

The imbalance required is in my opinion proportional to the load on the mount. With my setup it's such that if I am rotating the RA axis counterweights to the east, when I let the counterweight shaft go during rotation it comes to a smooth but decisive stop, if I give it an equal flick in the other direction it maintains momentum. That is with just 5kgs or less of gear. More gear on the mount, less imbalance is how I normally go.