"Not an expert, but when I started teaching in 1966, using the PSSC
text, the point of convergnce of the parallel rays was called "principal
focus". I have always liked that term and still use it my self."
(Ken Fox )
Ahhh. I like that also. Doesn't make it right, but I like it.
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu
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