Re: binocs

From: Jean-Luc L. J. DIGHAYE (
Date: Wed Jun 19 2002 - 16:00:22 EDT

Hi, just a brief comment:
The gain of 1.0 mag with 8x56 binos compared with 7x35 is somewhat
optimistic since it can only be reached under perfectly dark skies.
There are a number of online "limiting magnitude calculators" taking
several parameters, some of them physiological, into account. I
developed such an empirical model (please contact me personally for
details since this is rather off-topic). Under moderate light pollution
skies (ie Bortle 5 if you are familiar with the Bortle scale) I observe
a gain of 0.7 mag. Still enough, yet, to see twice as many stars,
satellites and debris...

"Matson, Robert" schrieb:

> Hi Jonathan,
> > I can usually get to magnitude +6, +7 (sometimes  +8 with averted
> > vision and squinting) with my binoculars, which are 7x35's.  Just
> > out of curiosity, would I see at least a marginal increase if I
> > were to switch to 8x56's (I am in my 20's, for pupil concerns) ?
> Absolutely, regardless of your pupil size.  The 56mm diameter
> objectives have 2.56 times the light gathering power of the 35's,
> which buys you a full visual magnitude, all other factors being
> equal.  If you have 7mm-diameter pupils (and well-corrected vision
> when your eyes are fully dilated) then you'll benefit from the
> larger binocular exit pupils of the 8x56's.
> --Rob

Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
in the SUBJECT to

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