From: Milton Aupperle <milton@outcastsoft.com>

Date: October 1, 2008 10:50:22 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Custom drive ratios disrupt tracking?

Dear KirkusMcGurkus;

On 1-Oct-08, at 1:08 AM, KirkusMcGurkus wrote:

I have an LXD75 that I've recently modified by replacing the motor

drive gears with a belt drive system. In doing so I've changed the

drive ratios in my Autostar. Can these changes cause tracking errors

with AstroIIDC?

I would imagine it could.

The reason I ask is that the last 2 nights, since modifying my mount,

when I begin tracking a star, both RA and DEC run off course by what

seem to be near equal amounts and in a very consistent manner.

Which version of Astro IIDC?

When observing the tracking star visually it moves off course very

slowly... my initial alignment has been good. But as soon as AstroIIDC

takes over (following successful calibration), these very consistent,

smooth errors in both axis appear. I have a screenshot if it would

help to clarify what I'm saying.

Are you sure it successfully calibrated? Did you watch the whole process to see if when it stops moving that the Red cross over the star is in the right place and not offset?

Also have you re-balanced your mount after all these modifications? I seem to recall you trying to guide with a 10" Scope which severely over weighted the mount and had tracking issues then too, is that the same thing now?

I guess I'm wondering if something needs to be modified in my

AstroIIDC software to compensate for the modification to my mount.

There is likely nothing we can change. We tell it to move for z period of time it is supposed to consistently move for z period of time. If it's inconsistent for movement or there is a lot of Lag / Delay then it won't track well that's all there is to it.

BTW, the new drive ratios, when using the mount without tracking, are

spot on.

That doesn't really mean much. Guiding needs repeatable consistent motion and if there is any lag / delays or over runs in motion, it won't track.

Milton J. Aupperle