Backlash in RA and DEC axes: normal or needs adjustment? - Forums

Topic starter

1 day ago

Hi everyone :)

A few days ago, out of curiosity, I removed the front and back covers of my mount to inspect the RA and DEC gears and check if everything looked fine. Overall, everything seems okay.

Here are a few pictures for reference:

DEC: https://drive.google.com/drive/folders/1z3bE1BAkExyO0WZOligBSvrcrupONj2q?usp=sharing

RA: https://drive.google.com/drive/folders/1mQB1L0r7jKXeGRSFYCbe70WJbSWwOunp?usp=sharing

However, with the motors powered on and clutches fully tightened, I noticed something when using the SynScan Pro app: when I reverse direction using the directional arrows, it takes about 3 taps on the arrow before the gears actually start moving in the opposite direction, it happens on DEC and AR axis in the same way.

Is this amount of backlash normal, or does it require adjusting the gear mesh or maybe on that kind of mount is not possible ?

While there is no visible backlash among the gears that move the endless wheel as said above no issue on DEC and AR axis !

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TiffsAndAstro

1 day ago

Set at 2 speed on synscan controller 3 taps would not be out of the ordinary for my sw GTi. It would be quite good.

How is your guiding, what mount is it?

Scott Badger

1 day ago

Backlash in RA generally doesn’t matter since you don’t reverse direction. PHD2 guiding assistant will tell you how much the DEC backlash is in ms and what settings to use to counter it.

To reduce it, adjusting the meshing is the place to start, or a ‘hyper tune’ might help, but with a Celestron CGEM I used to have, neither helped because the real source was inside the motor, which I couldn’t fix, and three replacement motors were the same or worse…..

Cheers,

Scott

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Roberto MR

Topic starter

1 day ago

TiffsAndAstro · Sep 19, 2026, 11:18 AM
Set at 2 speed on synscan controller 3 taps would not be out of the ordinary for my sw GTi. It would be quite good.
How is your guiding, what mount is it?

as said in the title is star adventurer GTI - guide quite good but i want to check if is possible to improve but i don’t think i can remove backlash in these in the motor reducer wheels because there is no possibility of making the adjustment

TiffsAndAstro

23 hours ago

Roberto MR · Sep 19, 2026, 01:45 PM
TiffsAndAstro · Sep 19, 2026, 11:18 AM
Set at 2 speed on synscan controller 3 taps would not be out of the ordinary for my sw GTi. It would be quite good.
How is your guiding, what mount is it?
as said in the title is star adventurer GTI - guide quite good but i want to check if is possible to improve but i don’t think i can remove backlash in these in the motor reducer wheels because there is no possibility of making the adjustment

Anyway I would leave it alone, and try to perfect your decision balance, which seems to effect mine. This is not too easy as the axis are a bit sticky.

As long as it guides ok, under your pixel scale, it should be fine.

What camera and scope are you putting on it ?

Roberto MR

Topic starter

4 hours ago

TiffsAndAstro · Sep 19, 2026, 03:05 PM
Roberto MR · Sep 19, 2026, 01:45 PM
TiffsAndAstro · Sep 19, 2026, 11:18 AM
Set at 2 speed on synscan controller 3 taps would not be out of the ordinary for my sw GTi. It would be quite good.
How is your guiding, what mount is it?
as said in the title is star adventurer GTI - guide quite good but i want to check if is possible to improve but i don’t think i can remove backlash in these in the motor reducer wheels because there is no possibility of making the adjustment
Anyway I would leave it alone, and try to perfect your decision balance, which seems to effect mine. This is not too easy as the axis are a bit sticky.
As long as it guides ok, under your pixel scale, it should be fine.
What camera and scope are you putting on it ?

i will use it with canon 2000d + Askar fma 180 pro.

i was not used to guide better then 1.5 arch/sec but maybe with more stable position for guide scope will improve