Re: [ATM] Secondary Cage Calculations (formula from Kriege + Berry's book)

[Alexis Cousein <al@sgi.com>]

Jacob Lauser wrote:
> Dave,
> 
> Does that mean only certain eyepieces are useable with the scope? 

Not really. Illumination drops off quite slowly beyond the fully
illuminated field, and it's customary to design only 70% illumination
at the edge of the widest field eyepiece (unless you're going to be
doing all your observing with it, obviously), in order to
limit the central obstruction.

See Mel Bartel's calculator at:

http://www.bbastrodesigns.com/diagonal.htm

and watch out -- the report is for the number of mm off-axis,
which is a radius, and should be compared with *half* of
the field stop in millimetres of a given eyepiece.


-- 
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>



-- 
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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