[Chaos-l] Canon IS Binoculars (fwd)

[Joseph Mack NA3T]

On Sat, 2 Feb 2013, MSN wrote:

> Joe, thanks for the quick and thorough reply.

Here's some more about exit pupil

http://www.cloudynights.com/item.php?item_id=348

> I'm 70 years old and I'm not sure what my pupil diameter is day/night.

you need to know this like you know your shoe size :-)

The method in "Astronomy Hacks" is the one I use.

http://books.google.com/books?id=piwP9HXtpvUC&pg=PA25&lpg=PA25&dq=determining+pupil+size+astronomy+hex+key&source=bl&ots=TbzjwwYqIY&sig=bycASQT7f_r3jOwwl7fFopwZ928&hl=en#v=onepage&q=determining%20pupil%20size%20astronomy%20hex%20key&f=false

Look for Fig 1.4 "Barbara measure her entrance pupil using an Allen wrench"

You only need to measure it once. It's not going to change.

All the best with your birding and astronomy

Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
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