Author Topic: Mirror cell design question.  (Read 586 times)

Mark

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Mirror cell design question.
« on: December 03, 2016, 10:01:06 PM »
I built a six point cell for a six inch primary, seen here.  I've been thinking of eliminating the three supports with six pads, and instead having six springs, sketched in red showing a new simpler single upper section.  Does anyone see a problem with six springs instead of the three supports and pads?  Essentially, there would be six individual spring loaded pads supporting the mirror.
« Last Edit: December 03, 2016, 10:10:40 PM by Mark »

mccarthymark

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Re: Mirror cell design question.
« Reply #1 on: December 04, 2016, 08:56:35 AM »
My logic as a non-engineer and a novice ATM:

Usually the mirror rests, either on the floating support points or silicone.  Its weight keeps it in even contact with the pads / supports during scope movement, holding collimation.  If the supports are springs, each of them presses up on the mirror with its own force, and the mirror would bounce around during scope movement -- probably would not hold collimation.  The springs might also somehow cause astigmatism -- putting uneven forces on the bottom of the mirror, or pressing the mirror against the retaining clips.

Your original cell looks like a great (tried and true) solution. 

--Mark
Mark

John Pierce

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Re: Mirror cell design question.
« Reply #2 on: December 04, 2016, 09:39:21 AM »
I wouldn't think a 6" mirror would need a 6-point suspension unless it was really thin... my 10" uses 3 points (really, 3 quarter-sized blobs of silicone about 1/8" thick) and is just fine.   the "plop" program calculates optimal suspension points for various configurations.