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Re: [ATM] Sling study
>From: Jarvis Krumbein <jkoptic@juno.com>
>The following oridinated with Richard Schwartz and was on the atm_free
>group.
>Every time you double the area, you must double the thickness. So you
>can imagine the series of numbers, 4, 5.6, 8, 11, 16, 22, just like
>camera f-stops, each requiring double the thickness of the previous size.
> This keeps the "span" constant. Since I was able to do an 8" x 3/8",
>the following table results:
>Diameter Thickness
>------------- ---------------
> 4" 3/32"
> 5.6" 3/16"
> 8" 3/8"
> 11" 3/4"
> 16" 3/2"
> 22" 3"
Note that these figures give a different thickness ratio for each size
mirror.
>This table is based on my experience with one thin mirror. Note that Mel
>Bartels once did an 8" x 1/4" mirror, so his thicknesses would be about
>2/3 of mine.
Note that this implies that experience/technique has an impact on whether or
not a given blank is 'thin' for one person...yet may be 'thick' for someone
else.
Again...no simple answer for a label of thin vs. thick. It depends on
performance...in this case it's a discussion of mirror-maker
performance...how thin can you successfully work a mirror blank?
-------------------------------------------
Tom Krajci
Cloudcroft, New Mexico
http://overton2.tamu.edu/aset/krajci/
Center for Backyard Astrophysics (CBA)
http://cba.phys.columbia.edu CBA New Mexico
American Association of Variable Star
Observers (AAVSO): KTC http://www.aavso.org/
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