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EAF Overkill?

CMOS Equipment Imaging
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#1 Jeff Morgan

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Posted 26 September 2021 - 10:23 AM

The ZWO EAF is supplied with four flex couplings, none of which fit the Tele Vue NP101is. Instead, I used a sprocket and belt as shown. In the thread where I saw this it was suggested to use the fine focus knob which sounded interesting and I did it. 
 

Of course one can not focus out the seeing. My thinking was with a larger number of data points, the algorithm for calculating the V-curve might derive a smaller variance closer to actual conditions. 
 

And the focuser certainly generates lots of data points! The autofocus cycle typically runs 4-5 minutes. Every new Go2. Every new filter. Every temperature change. It adds up. 

 

So is using the Fine knob a waste of time?
 

 

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#2 imtl

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Posted 26 September 2021 - 10:27 AM

My autofocus cycle with this scope take 60-80s with LRGB and 100-120s with NB. It depends on your camera setting as well.

I would use a higher grade EAF but that's a different story

#3 Der_Pit

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Posted 27 September 2021 - 01:37 PM

Usually™ it's a bad idea to use the fine focus knob:  They work on friction (steel balls and axle in a brass/steel cup), and like Crayford focusers they are sensitive to slip.  And losing steps is a bad idea for auto focus.  So I'd rather try to connect it to the coarse knob.  Stepper motors are good at making small steps - you don't really gain by making 100 steps instead of 10.


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#4 Jeff Morgan

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Posted 29 September 2021 - 03:15 PM

Usually™ it's a bad idea to use the fine focus knob:  They work on friction (steel balls and axle in a brass/steel cup), and like Crayford focusers they are sensitive to slip.  And losing steps is a bad idea for auto focus.  So I'd rather try to connect it to the coarse knob.  Stepper motors are good at making small steps - you don't really gain by making 100 steps instead of 10.

I will switch to the coarse knob for this new moon window to see how it does.

 

The software can also be set for fewer steps which should allow me to tune things a bit. 




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