[ATM] spider rotation

[Jerry]

About a week ago Arjan sent a link to such a design. Jerry must have missed
it.

	Arjan said...
	You mean this one: http://koti.phnet.fi/pulliy/second.html ?

Notice the curves on the top of part #2 and the bottom of part #3. They are
centered at the center of the mirror's surface. Tilt and rotation is
possible without changing the location of the center of the mirror surface.

More trouble than I would go through for something that I could do another
way. I do not like the mirror being on the end of a tuning fork tine. May be
if the curve of part #2 was the top of the Mirror attach piece and
adjustment along the main tube axis was by some other method than a
relatively thin rod I could use this idea. I adjust rotation at the
attachment to the spider, a tube almost as large as the diagonal minor axis.
Then tilt and depth in the main tube is done by spider leg attach points to
the main tube. Very solid that way. Adjustment lasts until the next time the
diagonal is removed from the tube for recoating. 



-----Original Message-----
From: Dale Eason
 
It seems to me that you are worrying about something
that is not an issue.  That is why you do not find any
plans for what you think you require.  I know of no
design that tries to keep the diagonal centered while
adjusting it. 


--- Jerry Hillman <truckeratm at sbcglobal.net> wrote:

> Hi All,
>   Can anyone direct me to a site that has built a
> spider that is not a variation of the common spider
> that everyone seems to use. Since the placement of
> the secondary mirror is so critical, I am looking
> for a design the uses the surface, center of the
> mirror as the rotation point, not the tip of a
> adjusting bolt that on my scope places the rotation
> point about 3 inches away. Makes for a frustrating
> time trying to adjust the mirror since centering the
> mirror moves it out of collimation and collimating
> it moves it out of center. I have about 1/8" offset
> but same problem applies. I can provide drawings
> that illustrate my problem.
>   Jerry
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 



 
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