celestron cg5 goto problem !!

[Alan from Acklam]

I have a recently purchased  200mm newtonian reflector mounted on a celestron cg5 goto mount .

This has proved very accurate at finding lots of objects and especially faint fuzzies. However i have had a mishap.!! When the scope was fast slewing to a high object the scope tube impacted the tripod leg and jammed.Now i find when i select alignment stars / calibration stars & objects the scope goes nowhere near to them.Have i knocked the motors/gears out of sync with the hand set command??

Has anyone else had this problem? Does anyone know of a fix for it??

Best Regards

Alan from Acklam

[rob0971]

Have you checked the polar alignment? Has it moved after the mishap?

[nmoushon]

You should have to reset and redo polar alignment and star alignment and that should fix it. Hopefully. The controler doesn't read the gear movement. It simpley tells the gears to move X amount. If you hold the scope from moving the controler can't tell  that it hasn't moved it still thinks the it has slewed to the target.

[Oddsocks]

It might depend on how you reacted when the scope jammed, if you turned off the power while the scope was still trying to slew then the handset software can become corrupted and the initial location coordinates are lost, or the backlash settings and RA index reference mark correction is changed so that pointing accuracy is reduced. There are a few postings on the Cloudy Nights forum where this had happened.

The solution on the CN threads was to return the handset to the default factory settings, see page 33 of the instruction manual, and then carry out a complete new initial calibration of the mount.

After that was done then pointing accuracy was restored and the alignment stars were once again seen in the eyepiece near to where they should be.

Link to the manual:

http://www.celestron.com/c3/images/files/downloads/1196122269_cg5mount9151791.pdf

[Alan from Acklam]

Hello everybody and thanks for all your replies. I have tried your suggestions and the problem is now fixed.

I have also contacted Beacon Hill Telescopes who is going to make me a steel tube pillar for the mount. I can then discard the tripod and will not have the problem again.

Best Regards and clear skies.

Alan