Re: Remote control collimation - ideas please

Rick Foust

Hey guys.  I appreciate the ideas.  I am leaning toward R32 + CNC V3.  Thank you Khalid for pointing that out.  I missed that addition to the Wiki (my Onstep is running so well that I haven't had to keep up with the latest new stuff).  I am sure it will fit in the shadow, although I may have to mount it in line with the OTA axis (on edge, so to speak).  And I think it will do everything that I want if I can make the secondary adjustable with only 2 screws.  I am thinking 2 screws/steppers will be enough if I drill out one screw hole and install a spring in place of the screw.  Then it would work like a common finder scope that has 2 adjustment screws and a spring.  The spring will have to be fairly stout to provide enough preload to prevent vibration or shifting.  There is quite a lot of leverage created by the cantilevered mirror and its holder.

In answer to some questions.  I really do need to fiddle with the secondary.  The primary stays rock solid and never needs adjustment.  No matter how well I collimate, it is never quite right once I install the camera.   I know it sounds a bit crazy.  I have 6", 8" and 10" Newts that don't have this problem.  It is a curse of the tube design combined the size.  I have made numerous modifications to stiffen the tube.  But they have not been enough. 

I plan to keep the motors de-energized when not adjusting.  Otherwise, I suspect that the heat would cause too much turbulence.  A fun experiment is to use night vision instead of an eyepiece.  Then, with the scope way out of focus on a bright star, hold your hand in front of the OTA.  You can clearly see the heat plume coming off your hand.

If I fail to make the 2 screw idea work, I will give the grbl firmware a try.  Thank you Alexander for suggesting that.  I was wondering which CNC firmware to consider.  Gcode and hexapod are new to me.  I will have to check them out.

If none of the above works out, I will go old school with switches and DC servo motors.  Might even be the best option.  Simplicity has its advantages.

Anyways.  Thanks again.  And if you have further ideas, I am all ears.

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