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Old 31-12-2018, 03:59 PM
Stefan Buda
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Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 823
Last day of the year and I'm ready for first light. Sort of.

Actually I did hit a problem with the focuser: The image shift during direction reversal is a bit worse than what I was hoping for. I hooked up a MyfocuserPro2 board to the stepper motor and used a test program to drive it back and fort while watching the crosshair target reflection with the Taylor Hobson. I was getting an image shift of about 0.25mm and I could not fix it, so I'm taking the front end back to the drawing board. I will make a new mechanism with 4 guide pins instead of 3, and if that still comes short on performance, then I'll move onto using miniature linear ball bearings.

Does anyone of you have any experience with commercial secondary focusers? I'm curious whether they produce any image shift on direction reversal. Zero shift seems like a difficult thing to achieve without making the mechanism much bulkier. I'd like to avoid that.
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Last edited by Stefan Buda; 31-12-2018 at 05:52 PM.
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