why will I have to disable the CGEM mount backslash with PHD2?

[Miguel Rivero]

Hi to all!

I being looking to improve my mount behavior due to backslash.

To do so I have looked in to the AR and Dec backslash adjustment but found out that there is a delay (aprox 2 seconds)  in the motors to move and have seen that I can have much better response with the CGEM backslash adjustment, but following the PHD2 I do have to disable it, does anyone in this forum know why would I have to disable it?

I share my PHD2 guiding assistance report! any comment, help or feedback will be appreciated.  (I have posted this issue in the  open PHD guiding, and  other)

Regards.

 

[scotty38]

Have you tried adjusting the balance at all? If you have it perfect at the minute then try going one way or the other and see what happens, basically try tweaking it to see if you can improve things before turning things off.

[alacant]

Hi

The star you chose is not suitable for guiding and especially not for the guiding assistant. Best to allow PHD2 to select a star.

But by far the best way to solve backlash issues is to dismantle DEC, clean, re-grease and adjust. This is especially true on new mounts direct from the factory. That software stand a chance, mass produced mounts need to be as mechanically perfect as you can get. There's a DIY kit with the parts and guidance you need.

If however you're not going to fix the mount, then the only way to tame 9000ms of backlash would be guiding DEC south only. 

Cheers and HTH

[Miguel Rivero]

Thanks, 

Probably will be good to consider fixing the mount as much as I can in the mean time I will keep in mind to use guiding DEC south only.

Regards.

[Miguel Rivero]

8 hours ago, scotty38 said:

Have you tried adjusting the balance at all? If you have it perfect at the minute then try going one way or the other and see what happens, basically try tweaking it to see if you can improve things before turning things off.

Thanks, yes I have no major change! 

REgards.

[michael8554]

A few mounts will dec guide better with PHD2 and the mount's Dec Backlash Correction on.

But usually they fight each other.

"I will keep in mind to use guiding DEC south only."

The direction to guide Dec in one direction is entirely dependant on the balance and where the mount is pointing.

Might be south when you did the GA run, but might be north when you swing to the target.

On target, switch dec guiding off and note which way dec drifts after a minute.

Set dec to guide in the opposite direction.

But ideally adjust the mount's Dec backlash.

Michael

[Miguel Rivero]

18 hours ago, michael8554 said:

A few mounts will dec guide better with PHD2 and the mount's Dec Backlash Correction on.

But usually they fight each other.

"I will keep in mind to use guiding DEC south only."

The direction to guide Dec in one direction is entirely dependant on the balance and where the mount is pointing.

Might be south when you did the GA run, but might be north when you swing to the target.

On target, switch dec guiding off and note which way dec drifts after a minute.

Set dec to guide in the opposite direction.

But ideally adjust the mount's Dec backlash.

Michael

Thanks Michael, I will do! 

Regards

Miguel.

[newbie alert]

Your backlash result shows the gear mesh is in no mans land as it reverses.. you can tinker and reduce this slightly but will never completely solve the issues.. I call it just a bad design fault.. cog to cog design will always have backlash, the servo motor cogs produce random spikes .. I'm belt modding, changing to steppers and changing the board on mine, basically getting rid of the Celestron train of thought and improving the design for hopefully much better performance..