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Celestron CG-5 Mount

Started by trikeriderdf, 09/18/2010 06:52PM
Posted 09/18/2010 06:52PM Opening Post
Hello all:
I just got a Celestron CG-5 mount new, and it came with no instructions. The manual I downloaded from Celestron does not seem to address this question. There is excellent help here on Astromart and on telescopeboy.com for rebuilding the mount mechanically, but I have a question regarding the RA and Dec motors.

These motors run on my model, but they will not turn the mount. There is a clutch (?) wheel for each that must be tightened for the motor gear to turn the worm shaft gear, and I have tried that wheel loose to tight in many different settings.

There is a lock lever on each axis which must be locked for the manual handles to turn the worms, and they work fine when that lever is locked. With the motors, I have tried these levers from locked to totally unlocked to no avail.

I think there must be something easy and obvious I am missing, but I am missing it. Any ideas? Thanks!
Sincerely,
Don French
Posted 09/19/2010 02:53AM #1
Don French said:

Hello all:
I just got a Celestron CG-5 mount new, and it came with no instructions. The manual I downloaded from Celestron does not seem to address this question. There is excellent help here on Astromart and on telescopeboy.com for rebuilding the mount mechanically, but I have a question regarding the RA and Dec motors.

These motors run on my model, but they will not turn the mount. There is a clutch (?) wheel for each that must be tightened for the motor gear to turn the worm shaft gear, and I have tried that wheel loose to tight in many different settings.

There is a lock lever on each axis which must be locked for the manual handles to turn the worms, and they work fine when that lever is locked. With the motors, I have tried these levers from locked to totally unlocked to no avail.

I think there must be something easy and obvious I am missing, but I am missing it. Any ideas? Thanks!
Sincerely,
Don French

Don:

I have owned a few CG-5 mounts both GOTO and non GOTO. In general they are reasonable mounts but have their issues...

First, you say your mount is new. To the best of my knowledge, the new CG-5s are all ASGT which means Advanced Series, GoTo. From your description, it doesn't seem like you have an ASGT mount. ASGT mounts do not have clutches nor do they have manual "slo-motion" controls. They do have locking levers.

The distinctive feature of the ASGT series is that they have 2 inch diameter stainless steel legs, these are quite apparent and very stiff. The older CG-5s used extruded aluminum legs which were spindly and prone to vibration. There were a few AS mounts made, the heavy duty legs but the older stepper motor non-goto drives but these are long gone from the shelves of vendors.

Anyway, do, I am not exactly sure what you have but it seems you have GEM with the clutches and the locking levers and most likely the stepper motor drives. If I remember correctly, these have 2x, and 8x slewing speeds.

About all I can offer is that even the high speed slewing is slow, 1x is one revolution per day so 8x is on revolution every 3 hours, that is pretty slow.

You should not expect immediate response, at those slower speeds it may take some time for the gears to catch up and for the mount to begin to move. This could probably be as much as 30 seconds.

As far as the locks and clutches. Both must be very tight, the clutches are notorious for slipping. They really have to be tight.

A few questions;

- What is the scope here? How well balanced is it? Have you tried the mount without the scope and without the counterweights?

Do you have a photo of the mount, maybe one of us can identify the problem is we have a better idea of exactly what you have and what is mounted on it.

Best wishes

Jon Isaacs