Need help -- Wheelchair bound friend interested in astronomy

wrote:
Just to clarify, my friend is quite mobile. Im not sure where his
paralysis begins, but he drives his own car and jockeys himself in
and
out like a pro. His wheelchair knocks down into a few pieces and he
hauls it into the car. So, he is fairly mobile, especially in the
upper
body, and he is strong, probably more than most of us that can walk.

Ultimately it is up to him. I suggested the pat "get a good pair of
7x50 binos and a couple of books and learn the sky." I think the idea
of a UniLight mount from UA as it can accomidate binos, refractors
and
even an 8" SCT. I just wonder about stablizing it during setup (ie
putting on the counterwieght, then the tube, etc)

Matt


The Unimount Light Basic and the Unimount Light Heavy, both excellent
for binoculars, would not be a proper mount for an 8" SCT. Anything
that would be appropriate also for an 8" SCT would be overkill for
binoculars, and would cost about $400 to $500, just for the mount.

The Basic with the 7.5# of counterweights is easily manuvered with one
hand to slide over the thripod mount post. The Deluxe is only a little
more cumbersome with the swivel head joint and 10# of counterweight.
Both easily handled. Since the mount would be used from a seated
position, the tripod would be extended only two leg sections. the top
of the mount post will be reached easily.

I would not recommend a 7x50 binocular as a first binocular. This is a
specialized binocular and it's performance will likely be compromised
unless all these necessary conditions are met.

First, it has a 7.1mm exit pupil, so unless you have eye pupils that
large, your eyes will reduce the effective aperture of the binocular.
If a 7x50 is used by someone with 5mm eye pupils, the performance is
equal to that of a 7x35.

If you have pupils large enough, because of the large exit pupil and
the very bright image it produces, if this binocular is being used in
skies that are anything brighter than very dark mag 6 or better, the
views will be washed out by the bright backgroung glow. In skies that
get only as dark as mag4 to mag 5, the 7x50 will act more like a 7x35.
A 10x50 in this case would be a better choice.

A magnification of 7x for astronomy is very low. Sure it's better than
1x eyes, but you see so much more as you increase magnification and the
consideration to use a mount leaves me thinking you want to be up in
the range of 10x50 (still low), 12x50, 12x60, 15x70 or 20x80. I'd go
for 15x70, because it has the best compromise of 4.3=B0 for and
magnification.

edz

Thanks. I suggested a 7x50 cause its easy to hold in your hands as
opposed to the giant astro binos.


wrote:
I would not recommend a 7x50 binocular as a first binocular. This is
a
specialized binocular and it's performance will likely be compromised
unless all these necessary conditions are met.

First, it has a 7.1mm exit pupil, so unless you have eye pupils that
large, your eyes will reduce the effective aperture of the binocular.
If a 7x50 is used by someone with 5mm eye pupils, the performance is
equal to that of a 7x35.

If you have pupils large enough, because of the large exit pupil and
the very bright image it produces, if this binocular is being used in
skies that are anything brighter than very dark mag 6 or better, the
views will be washed out by the bright backgroung glow. In skies
that
get only as dark as mag4 to mag 5, the 7x50 will act more like a
7x35.
A 10x50 in this case would be a better choice.

A magnification of 7x for astronomy is very low. Sure it's better
than
1x eyes, but you see so much more as you increase magnification and
the
consideration to use a mount leaves me thinking you want to be up in
the range of 10x50 (still low), 12x50, 12x60, 15x70 or 20x80. I'd go
for 15x70, because it has the best compromise of 4.3=B0 for and
magnification.
=20
edz

wrote:
Thanks. I suggested a 7x50 cause its easy to hold in your hands as
opposed to the giant astro binos.


wrote:
I would not recommend a 7x50 binocular as a first binocular. This
is
a
specialized binocular and it's performance will likely be
compromised
unless all these necessary conditions are met.


If hand holding is expected, you might want to consider 8x40, 8x42,
10x42 up to 10x50. But a binocular with a 7mm exit pupil (7x50, 9x63,
10x70) has special considerations and should probably not be considered
as a first choice, unless of course you can satisfy all the
requirements. Few people can.

Magnification makes it harder to hold the image still, but keep in mind
you see a lot more (with few exceptions) with higher magnification. A
12x50 will see 0.75 magnitude deeper than a 7x50. That's an awful lot,
considering 1.0 magnitude is 2.5x the light. If you're going to
consider mounting these binocs, don't go small on the magnification.

edz

simple. C8 on a sp low newtonian mount. Leg spread on tripod allows human
entry at front of a wheel chair. He may have to have someone set it up for
him.
This is what several here have done.



wrote:

Hey all-

I have a friend who has expressed interest in getting started in
astronomy. He is wheelchair bound. This unfortunately limits what types
of scopes and mount designs he could use. I was thinking that a
parallelogram type mount with some big binocs or a 4" refractor would
work as it would keep the scope/bino away from the tripod, giving the
necessary clearance, plus he could easily share his views with others
that are standing. I was wondering if anyone out there is or knows of
somebody in the same situation that could give me some tips or
suggestions. Thanks.

Matt