Re: [ATM] Secondary Offset

[Alexis Cousein <al@sgi.com>]

waldo kitty wrote:
> waldo kitty wrote:
>> the way i see it, there are three "angles" to work with as far as the secondary 
>> is concerned...
>>
>> 1. the distance (up and down the tube) from the primary
>>
>> 2. the distance (left and right) from the eyepiece
>>
>> 3. the angle at which the secondary is mounted.
> 
> errk! there's a 4th one, too... the twist around the tube's axis :?
> 
There are four degrees of freedom: two positional ones which you can
see from the focuser (to/from the mirror and orthogonal to it), one
positional one which is the placement away from the focuser, and
one rotational one (indeed easily visualised as being a rotation
of the holder on its central screw).

"Secondary offset" concerns itself with two positional ones: to/from
the mirror and away from the focuser. The third positional degree
of freedom needs no offset, and the rotation of the secondary is
another issue.


-- 
Alexis Cousein                                  al@sgi.com
Senior Systems Engineer/Solutions Architect     SGI/Silicon Graphics
--
<If I have seen further, it is by standing on reference manuals>

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