Since I brought my Celestron Nexstar 130 SLT in common luggage on my flight back to Brazil,

I think it was hit and, once operating, there was an error on the azimuth control, which makes continuous

tracking of objects virtually impossible. I actually thought it was a mechanical issue, but I was afraid that

it was difficult to open and fix it. I was wrong. This fix is very very easy and I am impressed with the results.


Symptom: By using the cursors, at rate 9 (faster speed) the movement of the azimuth does not responds quickly as you

change the direction of the control; but you can hear the motor running, despite it does not moves for a few seconds.

Once moving, it is OK, but if you reverse the direction of the manual azimuth movement with the control pad,

the telescope does not responds immediately by changing the movement direction.


It is a mechanical issue on the main gear inside your telescope base.


1 - dismantle you telescope base and remove the 2 Philips screws and also the 1/2" nut below the

base rotator.




2 - using ONLY you hands, remove carefully the bottom cover of the base. You have to be strong, but do a perpendicular

movement, firmly pulling the base towards you, but without twisting or tilting the bottom cover.

Take care to do not touch the grease. Otherwise you will have to replace it.



3 - once the bottom cover is released, you will see the main gear beneath the base body.

This gear is attached to the body by 2 M3 (3mm standard type) screws.

In my 130SLT, these 2 screws were untighten. This made the gear to move a little all alone, without properly

moving the base body and the telescope arm that is tied to it.



4 - I thought that to be certain that, once locked by a good screwdriver, it will not be once again released,

but to be certified I changed these 2 screws by 2 little bigger screws (from 10mm to 14mm lenght),

 and added one pressure washer on each screw.


5 - after tightening the two screws with the nut, all parts were put on their places, and the telescope was reassembled.

Take care when the bottom cover is to be inserted. Maybe it is needed to loose the screws, put it softly,

then tighten the screws slowly. These attempts are needed to make the gear to be placed in the right position

and do not force the small gear on the gearbox near the azimuth motor driver.

I had to make 3 attempts before finish. If you have more lucky than myself, you will need less than that.


Once again, just use your hands, and do not exaggerate when forcing. If you feel too much strenght is needed,

something is wrong.

When placing the bottom cover back again, better use try and cut, with extra careful observation.





PLS check my other astro pictures at CelestronImages website


How to attach Sony Nex-F3 to the 2" port of NexStar 130 SLT