Worm Gears And Tracking Mounts - HELP!

[Wedge]

Hi All,

I currently have the Celestron Motor drives installed on my GC-4 Mount. I have used them successfully to track some objects for visual use, but I would soon like to do a bit of DSLR photography and want to make sure they are in top-working condition!

I have noticed that when I use the buttons on the remote to centre the FOV, it is a little slow to respond and I think that this problem is adressed in the instruction manual:

(click to enlarge)

HOWEVER: I find this waaaayyy to vague, and I need a little guidence.

For example, which bits are the worm assembly?

Are they these bits:

(click to enlarge)

(click to enlarge)

If so, do I simply have to keep playing with them until the motors respond quickly?

ALSO:

I know that a polar scope is recommended for accurate aligning. I have not yet bought one however because there already seems to be SOMETHING where it would go...

(click to enlarge)

If you look through it you can see cross hairs and a little circle to the side which I imagine is for Polaris - the 'scope came like this, so is it actully a polar scope? If not, what is it?

Thanks for all your help and sorry about all the pictures and if my post doesn't make sense.

Hoping to get some good images tonight 8)

Remy.

[GazOC]

Yep, thats the polar scope.

[Wedge]

Really!?

That's great as like I said, the 'scope came with one!

Is it the same as this?

http://www.firstlightoptics.com/proddetail.php?prod=Celestronpolarscope

Remy

[GazOC]

Yep.

[Wedge]

Like I said - Great!

What about the worm assemblies? Are they the pieces that I have photographed?

[GazOC]

Yep, those are them, the worm gears are in the "boxes" that attach to those brass stubs in your photo.

[MartinB]

Remy, unless your backlash is very bad I wouldn't bother with making any adjustment. Some backlash needs to be present. If you are imaging unguided then backlash isn't an issue since the RA movement is in the same direction and dec isn't doing anything. If you move to guiding then the guide corrections can all take place by the RA rate simply slowing down to 0.5 sidereal rate so again no problem. Dec is more of an issue and the best way to get around this is to make the dec balance sufficiently off to keep the gears meshed through gravity.

I have had a couple of Vixen Polaris mounts which had a fair bit of backlash. I spent hours tweaking them, then I fiddled with backlash compensation both with the handset and in Maxim. Finally I gave up fretting about backlash and just offset the dec balance. End of problem. Just don't overdo the dec imbalance thing!

[Wedge]

Great - this was the info I needed to know!

Thanks for the Advice and help

Remy