[ATM] Re: Banishing the secondary

[artbianconi@blast.net]

The following is part of a message I received today from Dave 
Groski about building the Schief design:

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"Hi Art,

Don Surles is still thinking about having a class on making
the Schief. It's really a matter if we can offer a project that 
can be done at the mirror making weekend with a high probability 
of success.

We also thought about getting together once a month or so. Just 
need to work it out with Don and see how many people would be
interested.

I saw a couple of notes in the ATM.list  archive  that you posted
about Bill's Schief. I don't subscribe to the list so I can only 
view messages in the archive up to mid July. If anyone has a 
question just send them my way. 

The key point is that my design is an improved version that has 
reduced the total aberration to around 1/10 wave for the 4.25", 
5" and 6" versions while still keep the opticals spherical and 
with the same radii so the convex tool can be used as the 
secondary. 

The negative is that these are slow f-ratio 'scopes ( f 27 to 
f30) and the 5" and 6" version with have long tubes. In theory 
they have less aberration then a refractor and will be easier and 
less costly to make.

          - Dave"
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