Re: binocular image size

On or about Thu, 28 Feb 2008 12:11:32 -0800 (PST) did scooter
<codecutter@xxxxxxxxx> dribble thusly:

Hey folks, Not sure if this is the right group, but must be close...
I'm an amateur telescope guy, who years ago bought a binoviewer, (they
are, or are like, attaching a binocular set onto your telescope i.e.
let you see the object with two eyes, keeping the single objective.)
So, over the years, I have been become more convinced - that when
using a binoviewer', and comparing it with the image I saw with one
eye in the telescope, that the binovewer image is larger, both from a
subjective, 'in our minds eye' sense, and to any attempt at reasonably
measure it. (that I've come up with).

The binoviewer might increase magnification itself, but it will
definitely increase magnification if it has a built-in or attached
Barlow lens to increase the telescope's back focus (which is usually
necessary for Newtonians and refractors, but not SCT's).

Further, well if you were to ask me, ;-) it now seems arguable that
the idea can be more general - a binocular image, that is, using just
your eyes (i.e. no binoviewer) provides an increased field of view of
an object, than does a single eye view.

Well, no. Using two eyes increases your field of view, because they
have a horizontal separation, so the combined FOV is greater than that
of either one.

Through a binoviewer, however, there's no difference in the FOV,
because both eyes are receiving the same light from a single
objective. And since FOV goes down as magnification goes up, you
actually have a smaller FOV through your binoviewer than just through
the eyepiece in question, if you're correct about it magnifying (which
you probably are).

One way to find an objective difference between the output of an EP
through the binoviewer and its output directly in the focuser (or
diagonal) is to take a picture of the same field with the camera in
fixed position. Not necessarily easy, if you don't have the right
equipment, but it's doable.
--
- Mike

Ignore the Python in me to send e-mail.
.

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