ATM Exit Pupils & Big Scopes

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

Exit Pupils & Big Scopes --

Val Germann
Central Missouri Astronomical Association

Back in the early 1980s, when the Coulter big dobs first
came out, we began to see problems due to the power being
too low and exit pupil too large.  I ran some experiments
back in 1982 and found that entrance pupils for our
members ran the gamut from 5mm on up to about 8mm -- in
general decreasing with age.  I'm 47 now and my entrance
pupil is only about 5mm, even in very dark conditions.

For those embarking on big projects it might be useful to
know your own personal entrance pupil. . .and what it is
likely to do (change) over the next decade or so.

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