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Re: [ATM] Re: Off-centered Mirrors?
On Mon, 25 Oct 2004, Cross, Timothy wrote:
> Don,
> These off-axis Newts are currently made by DGM Optics
> (http://users.erols.com/dgmoptics/), and Orion has just joined the fray with
> a 3.6" (or 3.8"?) off-axis reflector
> (http://www.telescope.com/jump.jsp?itemID=77066&itemType=PRODUCT&path=1%2C2%
> 2C4%2C8&KickerID=429&KICKER); these are all presumably made by cutting
> primaries from large, parent parabolic mirrors (i.e. you might cut 4 4"
> mirrors from a 10-12" parent mirror.
Ouch! Isn't that pretty expensive use of glass and optical shop
resources just to get rid of some obstruction on a tiny mirror.
I can't imagine making a nice 10-12" parabolic mirror and then
cutting it into 4 little 4" pieces. Does this somehow work out
economically? Are 4" unobstructed mirrors really that popular?
What is the rationale?
Dominic-Luc Webb
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