Re: scope vs binoculars

[miaim@mebtel.net]

Most astronomers and the better target shooters keep both eyes open when using 
monocular optics. I've done it instinctively for as long as I can remember and 
using a spotting scope for birds is no different.

Getting back to large binoculars vs. scopes, there has been a good bit of 
discussion on various forums about the value of binocular vision vs. monocular 
vision. Amatuer astronomers who've tried very large binoculars and/or 
binoviewers on their telescopes often report seeing more detail and more subtle 
coloration with binocular views even when compared to slightly higher 
magnification monocular views.  I've proven to my own satisfaction that I see 
enough more detail using binoculars over monoculars to compensate for some 
increase in magnification and objective size. For instance, a really top grade 
set of 12x50 binoculars (such as Nikon SE) can pretty easily compete with most 
15x60 spotting scopes. Likewise, the better 15-16x70 binoculars (such as 
Fujinon FMT-SX 16x70) binoculars can fairly easily show as much or more detail 
as most 20x70 spotting scopes. But keep in mind, the binocular vision ability 
to discern more is fairly limited by small increases in magnification when 
comparing binos to scopes. A 16x70 binocular or 20x80 binocular won't compete 
with a good 70-80mm scope at 30-60x. 

The real problem with big binoculars is that they're heavy and require a mount. 
Realistically, anything above about 12x50 should be mounted. For some folks 
that threshold is much lower and ALL binoculars will show better views when 
mounted. By the time one factors in a good tripod, and suitable head or mount, 
large binoculars can actually get considerably more cumbersome to use in the 
field for pursuits such as birding. The other problem with most large 
binoculars, is that until fairly recently, binoculars were limited to one, 
fairly low power. Whereas spotting scopes can often handle much higher power. 
This has recently begun to change somewhat with more and more really large 
binoculars beginning to accept standard telescope eyepieces. However, really 
large binoculars like that are VERY expensive. They can easily cost as much or 
more than a similar aperature spotting scope, and they are frequently 
*extremely* heavy and not at all practical to drag into the field. 

Recently, their have been several Asian imports that seek to address many of 
these issues such as cost and weight and they keep getting better all the time. 
I've used Pentax PCF V 16x60, Fujinon FMT 16x70 (VERY heavy) and Oberwerk 15x70 
binoculars in the field for birding. NONE really replace a good spotting scope 
in my opinion, but all are capable of giving really good views of the night 
sky. So, for me, the role of the large binocular is mainly for backyard 
astronomy and fixed position viewing. However, having said that, I'll also say 
that I typically take to the field with the max apperature and magnification 
binocular that I can comfortably carry and handhold. For me, that works out to 
12x50, but many folks would be better served with a good light set of 10x50s. 

Regards from an optics junkie,
Mike Swaim
Orange Co. NC
miaim@mebtel.net 

Quoting Charlotte Goedsche <goedsche@mindspring.com>:

> Reading John's postings on his new BIG binos brought back an old memory from
> high school chemistry class. The teacher told us to keep both eyes open when
> looking through a (monocular) microscope. I wasn't very successful at that,
> but when I remember to do so (i.e., infrequently) I try to use our scope
> that way. The brain seems to be able to pretty much ignore the input from
> the second eye if it is concentrating on those peeps in the distance through
> the other eye. I haven't tried this when it's really sunny out and I'm
> facing into the sun, though.
> 
> How about those of you who use a scope a lot? Does anyone keep both eyes
> open?
> 
> Charlotte
> Charlotte Goedsche
> Weaverville NC
> goedsche@mindspring.com
> 
> 
>