CG-5 problem causing a headache!

[Marcus10]

Hi, I have a C10 NGT mounted on a CG-5 mount. I have a problem that is proving very frustrating. Whenever I slew to an object that is close to overhead, the OTA invariably ends up hitting the tripod legs. This then throws out my alignment and means I have to start again, adding calibration stars etc.

How far up/down the dovetail should I mount the OTA to minimise this issue whilst still maintaining overall OTA balance? Also, is there a setting within the hand controller that will prevent it from slewing to a point where it will hit the tripod legs?

Your help is much appreciated.

[Marcus10]

Just as a follow up to this, I have done some research and noted that the alignment peg was fixed between the tripod legs rather than over one of the tripod legs. I've removed this and put it in the correct peg hole. Not sure if this makes any difference!

[mithrandir]

Quote from the manual:

R.A. Limits - Sets the limits that the telescope can slew in Right Ascension (R.A.) The slew limits are set to 0º to 180º; with zero being the position of the telescope when the counterweight bar is extended out towards the west and 180º being the position when the counterweight bar is extended out toward the east (see Fig 3-3). However, the slew limits can be customized depending on your needs. For example, if you are using CCD imaging equipment that has cables that are not long enough to move with the telescope as it slews across the sky, you can adjust the R.A. slew limit on the side of the mount that is restricted by the cables. Using the example above, the user could slew the telescope in R.A. until it reaches the point that the cables are extended to their maximum. Then by displaying the telescopes R.A. in this position (by looking at Get Axis Position under the Utilities menu) you can determine the telescopes R.A. at its most extended position. Enter this azimuth reading for either the maximum or minimum azimuth slew limit to ensure that the telescope will not slew beyond this point.

So set up the OTA, align the mount, and slew it in RA and Dec until you are about to bump into a leg. Get the azimuth from the mount. You could probably do this with an inclination gauge too.
Flip to the other side of the meridian and repeat.
Put the values into the mount via the hand control.

You might find values like 5 and 175 might be enough.

Or you could replace the mount with a pier - fixed or portable.

Yes, the peg is supposed to be over a leg, but it won't stop you needing to set the slew limits.

[Marcus10]

I'll give this a try and hopefully it fixes the issue - thanks

[Andrew C]

Has anyone had any experience with actually using the azimuth limit setting function on a Celestron Nexstar? I have tried to set custom values to avoid the problem Marcus talks about but the hand controller doesn't accept them.