ATM Images Sixteen Times Brighter

["M.E. Germann" <CCMEG@MIZZOU1.missouri.edu>]

Images Sixteen Times Brighter --

Val Germann
Central Missouri Astronomical Association

Yes, indeed, if you double the aperture you pack
four times the light into an Airy disk one-fourth
the area.  This is EXACTLY the way Celestron showed
that a C-8 was much better than any smaller telescope;
I have the late 1970s ad filed away somewhere!  Only
one problem, of course: the bigger scope has to actually
get that light into the Airy disk -- no mean feat!!

Is it sixteen times as hard to to make a 44-incher put
light into the Airy disk as it is to get a 22-incher to do
that very same thing!  Is that the rub!?

It seems that 16- to 20-inches is the break point.  That
is, it seems that up to that aperture many amateur mirror
makers (AMM, trademark) can turn out a very smooth piece
with a good edge and few small zones.  Beyond that things
get much dicey.  Is this a correct impression?

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