RE: [ATM] side obstruction

["Jerry" <wa4guu@verizon.net>]

Stand back baby! We don't know how big this is going to get.
Just what ATM has been looking for. Less aperture with bigger glass.

Jerry



-----Original Message-----
From: atm William Chang


>>

Two ideas come out of this observation.

(1) Deliberately truncating the aperture shortens the light
path, so a smaller secondary (CO) could be used.  What is the
quantitative trade-off of losing 10/12.5/15% on an edge, vs
a 2/2.5/3% reduction in CO (assuming f/5)?

(2) Truncate the mirror on two opposite sides by 10-15% each.
Now the scope can be made 20-30% narrower which has significant
mechanical advantages (in large apertures).  The loss of light
is insignicant (about 10% area), and the contrast effect ought
not be visible, again based on simple experiments.

I proposed such a "SlimScope" on SAA and AstroMart, and even
considered commissioning a 20" thin mirror truncated to 15" width,
for airline carry-on (!).  I'm serious.  Anyone here up to the
task? :-)

Also, if anyone has a badly chipped mirror, I know what to do
with it!

-- William (Saratoga, CA)




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