RE: binocs

From: Matson, Robert (ROBERT.D.MATSON@saic.com)
Date: Sat Jun 15 2002 - 21:04:22 EDT


Hi Linda,

Steve's binocular suggestions are all good.  I can add a few
more suggestions.  If the binoculars you'll be buying will
be used primarily at night, then you'll want to match up
the size of the exit pupil with the diameter of your own
dilated pupils.  Depending on your age, your pupils could
be 8mm, 7mm, 6mm or less (getting smaller as you age).

To determine the exit pupil size for a pair of binoculars,
divide the objective size in mm (the second number) by the
magnification (the first number).  For example, 7 x 50
binocs have an exit pupil of (50/7) or ~7 mm.

I use 8 x 56 binoculars made by Celestron -- it's just
about optimal for satellite viewing.  A little more power
than the 7 x 50's, but still relatively lightweight.  Beyond
8x, it's difficult to hold the image steady (though if you're
willing to spend a lot of money, they do make image-stabilized
binoculars).

Best,
Rob

-----------------------------------------------------------------
Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
in the SUBJECT to SeeSat-L-request@satobs.org
http://www2.satellite.eu.org/sat/seesat/seesatindex.html



This archive was generated by hypermail 2b29 : Tue Jun 25 2002 - 20:50:33 EDT