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Setting Up ZWO EAF with the Edge 8" for the First Time

ZWO ASIAIR Plus ZWO EAF Focuser Auto-Focusing EAA
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Jerry Gerber avatar
Jerry Gerber avatar
I have some questions: 

1.  What constitutes 0 position?  Does this mean when the scope is in focus? 

2. The AF exposure time defaults to 2".  Is there any situation in which this should be changed? 

3.  What does "Reverse" do? 

4.  I don't have any USB 2.0 ports left on my ASIAIR Plus, the mount and guide scope are using them.  Can I plug the EAF into the USB 3.0 port?

5.  What value do I input for "Backlash"?  

Thanks!

Jerry
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Quinn Groessl avatar
Quinn Groessl avatar
1. I set my  zero position to be when the focuser is all the way in. After is set that, I moved it all the way out and used that for max steps. I did set my 0 and max slightly less than the full travel, like 50 steps or so, but I figure I'll never use those focus positions anyway.

2. I have my LRGB filters set to 2", and my SHO filters set to I think 6 or 8 seconds or something like that.

3. I don't remember exactly what reverse does, but I had to turn it on for mine. If I remember correctly, I could have left reverse off if I set my 0 position to be all the way out on the focuser.

4. Yes you can. I have mine plugged in to an empty port on my  ZWO camera because on my  ASIAIR Plus all the ports are taken.

5. The third to last page ofthe manual explains it well, but that's tailored to crayford style focusers. Essentially you'll have to use the rough movement in or out, then the fine movement the opposite direction until your focuser moves. However many times you had to move in the fine times whatever step size you have set is what you put there. Like for me, I went out with 100 steps using the rough movement. Then in 3 times with the fine movement. My fine is set to 5. So 3*5=15, so 15 is what I put in for my backlash measurement.
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Jerry Yesavage avatar
Jerry Yesavage avatar
Hi,

Just saw your post by chance.  I have set up the EAF for an Edge 11.  It works fine to my relief.  I am using FocusMax for the focusing.  It took several days to get all the settings correct.  I have my mirror backlash I recall set in FocusMax to a very large number.  Like 400 steps… much larger than I thought I would need, but the developer worked with me on it. 

Good luck and send me a PM if you want any settings eventually.  I do not monitor the forums. 

JY
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Jerry Gerber avatar
Jerry Gerber avatar
With an SCT like the Edge 8, final focus should always move counter clockwise. 

So how does the EAF know to approach the precise focus from a counter clockwise move? 

If I have to do it manually it will undo the precision, which is the reason I got the EAF in the first place!
Tom Boyd avatar
Tom Boyd avatar
3. I don't remember exactly what reverse does, but I had to turn it on for mine. If I remember correctly, I could have left reverse off if I set my 0 position to be all the way out on the focuser.


It changes the physical direction the focuser moves when you hit the increase focuser distance (up arrow) from your zero position. On both of my scopes, I had to turn reverse on. Otherwise hitting the up arrow actually move the focuser in rather than out.
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Greg Erianne avatar
Greg Erianne avatar
Quinn Groessl:
1. I set my  zero position to be when the focuser is all the way in. After is set that, I moved it all the way out and used that for max steps. I did set my 0 and max slightly less than the full travel, like 50 steps or so, but I figure I'll never use those focus positions anyway.

2. I have my LRGB filters set to 2", and my SHO filters set to I think 6 or 8 seconds or something like that.

3. I don't remember exactly what reverse does, but I had to turn it on for mine. If I remember correctly, I could have left reverse off if I set my 0 position to be all the way out on the focuser.

4. Yes you can. I have mine plugged in to an empty port on my  ZWO camera because on my  ASIAIR Plus all the ports are taken.

5. The third to last page ofthe manual explains it well, but that's tailored to crayford style focusers. Essentially you'll have to use the rough movement in or out, then the fine movement the opposite direction until your focuser moves. However many times you had to move in the fine times whatever step size you have set is what you put there. Like for me, I went out with 100 steps using the rough movement. Then in 3 times with the fine movement. My fine is set to 5. So 3*5=15, so 15 is what I put in for my backlash measurement.

Hi Quinn,

Can you be a little more explicit on what you mean by the focuser being "all the way in" or "all the way out" in terms of the focus knob on the EdgeHD or in terms of the direction the EAF is turning to get to those positions?  Thanks!  (It's not your post that's confusing -- I'M confused and trying to figure out how the mirror moves in my EdgeHD 8 and how CCW and CW turning of the EAF is related to it all!)

Thanks!

Greg
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Quinn Groessl avatar
Quinn Groessl avatar
I was thinking of my refractor with in and out. 

As for your SCT, from what I understand CCW pushed the mirror towards the corrector and CW pulls the mirror towards the camera. It’s really not so important, but you’ll want the final move of an autofocus routine to be CCW.
Greg Erianne avatar
Greg Erianne avatar
Quinn Groessl:
I was thinking of my refractor with in and out. 

As for your SCT, from what I understand CCW pushed the mirror towards the corrector and CW pulls the mirror towards the camera. It’s really not so important, but you’ll want the final move of an autofocus routine to be CCW.

Ah, okay thanks so much, Quinn!  I understand and thank you again for replying.

Best,
Greg
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