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Ioptron CEM60 and TEC140 Guiding Issues

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5 replies to this topic

#1 RenaudVL

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Posted 04 February 2023 - 05:44 PM

Hello,
I am having difficulties getting a good guiding graph with my CEM60 and a TEC140 mounted with a Sharpstar 61mm as a guide scope on top.

I used to have great guiding with a C9.25 Edge and a Takahashi CN-212 both mounted with the same guide scope at a guiding rate of 0.5.

My balancing is very good using 3D weights in Ra and Dec. And I know that the weight is not the issue!

I have tried changing the guidie rate to 0.9 with no real effect/improvement.
Would it be the inertia of such a long telescope that makes it so?

What guide rate are you guys using?

Any help and suggestions would be greatly appreciated.
Thank you!



#2 DuncanM

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Posted 04 February 2023 - 06:00 PM

Hello,
I am having difficulties getting a good guiding graph with my CEM60 and a TEC140 mounted with a Sharpstar 61mm as a guide scope on top.

I used to have great guiding with a C9.25 Edge and a Takahashi CN-212 both mounted with the same guide scope at a guiding rate of 0.5.

My balancing is very good using 3D weights in Ra and Dec. And I know that the weight is not the issue!

I have tried changing the guidie rate to 0.9 with no real effect/improvement.
Would it be the inertia of such a long telescope that makes it so?

What guide rate are you guys using?

Any help and suggestions would be greatly appreciated.
Thank you!

Do you have good wind protection?

 

If you have recently changed your gear switch positions, you may want to check for excessive backlash in the RA and Dec axis of the mount: very gently move the CW shaft side to side and see if you can detect backlash in RA, if so, turn the RA gear switch (engage) in tiny increments until the backlash is gone. Test the mount for stalling by slewing at max rate from horizon to horizon in RA. Repeat the process for Dec by gently moving the OTA back and forth.

 

I recently had the same issue and the above procedure cured it completely.


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#3 RenaudVL

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Posted 12 February 2023 - 11:18 AM

Still no answer on what is the recommend guiding rate for the CEM60?

 

Thanks



#4 DuncanM

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Posted 12 February 2023 - 12:02 PM

Still no answer on what is the recommend guiding rate for the CEM60?

 

Thanks

I use .3 or .4 when using an OAG with a 10in F5 OTA, or .5 using a 50mm F4 guidescope. I increased the guide rate to .9 when guiding on comets.



#5 RenaudVL

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Posted 12 February 2023 - 03:37 PM

I use .3 or .4 when using an OAG with a 10in F5 OTA, or .5 using a 50mm F4 guidescope. I increased the guide rate to .9 when guiding on comets.

This is most helpful! Thank you

For some reason, I never thought of going under 0.5  undecided.gif


Edited by RenaudVL, 12 February 2023 - 03:55 PM.


#6 DuncanM

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Posted 12 February 2023 - 04:38 PM

This is most helpful! Thank you

For some reason, I never thought of going under 0.5  undecided.gif

I try to set the guide rate and aggressiveness so that the mount will not over correct during guiding.  The PE is low enough on my CEM60 and CEM120 that frequent and/or rapid guide corrections will probably just be chasing the seeing.


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