Converting spotting scopes to binoculars

Has anyone here given much thought to constructing a pair of binoculars from
a pair of spotting scopes? Any links to successful or unsuccessful
projects?

I was looking at the Pentax 80mm ED spotting scope. This one was designed to
accept standard 1 1/4 eyepieces and got rave reviews on the Better View
Desired site. The ED glass gives it superb color correction.

The advantage of using spotting scopes over telescopes is that the correct
image prism system is already in place. For me, one of the main benefits of
binoculars is that you get a correctly oriented image. Bino-scopes generally
give a L-R reversed image and this would put me off.

Mounting spotting scopes side by side there would be a problem with getting
the interpupillary distance small enough. However, the Pentax spotters (as do
many others) have the eyepiece "raised" above the objective axis by the
correcting prism. So if you were to rotate the left tube clockwise and the
right tube counter clockwise, you could narrow the IPD to the degree desired.


With the Pentax I mentioned above, I've since learned that it even has a
rotating tripod adapter that allows you to rotate the scope along its optical
axis while mounted. This would allow me to angle in the eyepieces for
adjusting IPD. The only catch is whether the rotating tripod adapter is
precise enough for the system to maintain collimation when being rotated.

Collimation of the tubes could be accomplished by placing a reticle eyepiece
in each tube sequentially and aligning it similar to a finder tube.

Does this sound like a feasible idea. The Pentax ED spotter goes for around
$750 so you could get some killer binoculars for around $2000 including
eyepieces.

The Pentax 80ED has a 504mm Fl. This means with a 24 Panoptic I would get 21x
with a 3.24 degree FOV. That would be really sweet.

Bill Tschumy wrote:

Has anyone here given much thought to constructing a pair of binoculars from
a pair of spotting scopes? Any links to successful or unsuccessful
projects?

I was looking at the Pentax 80mm ED spotting scope. This one was designed to
accept standard 1 1/4 eyepieces and got rave reviews on the Better View
Desired site. The ED glass gives it superb color correction.

The advantage of using spotting scopes over telescopes is that the correct
image prism system is already in place. For me, one of the main benefits of
binoculars is that you get a correctly oriented image. Bino-scopes generally
give a L-R reversed image and this would put me off.

Mounting spotting scopes side by side there would be a problem with getting
the interpupillary distance small enough. However, the Pentax spotters (as do
many others) have the eyepiece "raised" above the objective axis by the
correcting prism. So if you were to rotate the left tube clockwise and the
right tube counter clockwise, you could narrow the IPD to the degree desired.


With the Pentax I mentioned above, I've since learned that it even has a
rotating tripod adapter that allows you to rotate the scope along its optical
axis while mounted. This would allow me to angle in the eyepieces for
adjusting IPD. The only catch is whether the rotating tripod adapter is
precise enough for the system to maintain collimation when being rotated.

Collimation of the tubes could be accomplished by placing a reticle eyepiece
in each tube sequentially and aligning it similar to a finder tube.

Does this sound like a feasible idea. The Pentax ED spotter goes for around
$750 so you could get some killer binoculars for around $2000 including
eyepieces.

The Pentax 80ED has a 504mm Fl. This means with a 24 Panoptic I would get 21x
with a 3.24 degree FOV. That would be really sweet.

You can't just rotate the tube - the images must be coincident. See
http://www.page.sannet.ne.jp/mazmoto/intro-e.htm for discussion ...

On Mon, 26 Jul 2004 15:53:11 -0500, lal_truckee wrote
(in article ):

Bill Tschumy wrote:

Has anyone here given much thought to constructing a pair of binoculars
from
a pair of spotting scopes? Any links to successful or unsuccessful
projects?

I was looking at the Pentax 80mm ED spotting scope. This one was designed
to
accept standard 1 1/4 eyepieces and got rave reviews on the Better View
Desired site. The ED glass gives it superb color correction.

The advantage of using spotting scopes over telescopes is that the correct
image prism system is already in place. For me, one of the main benefits
of
binoculars is that you get a correctly oriented image. Bino-scopes
generally
give a L-R reversed image and this would put me off.

Mounting spotting scopes side by side there would be a problem with getting
the interpupillary distance small enough. However, the Pentax spotters (as
do
many others) have the eyepiece "raised" above the objective axis by the
correcting prism. So if you were to rotate the left tube clockwise and the
right tube counter clockwise, you could narrow the IPD to the degree
desired.


With the Pentax I mentioned above, I've since learned that it even has a
rotating tripod adapter that allows you to rotate the scope along its
optical
axis while mounted. This would allow me to angle in the eyepieces for
adjusting IPD. The only catch is whether the rotating tripod adapter is
precise enough for the system to maintain collimation when being rotated.

Collimation of the tubes could be accomplished by placing a reticle
eyepiece
in each tube sequentially and aligning it similar to a finder tube.

Does this sound like a feasible idea. The Pentax ED spotter goes for around
$750 so you could get some killer binoculars for around $2000 including
eyepieces.

The Pentax 80ED has a 504mm Fl. This means with a 24 Panoptic I would get
21x
with a 3.24 degree FOV. That would be really sweet.

You can't just rotate the tube - the images must be coincident. See
http://www.page.sannet.ne.jp/mazmoto/intro-e.htm for discussion ...

I don't see a page there that explains this. Can you give me a more direct
reference?

I don't see how rotating the tube should matter. With a porro prism the
image will remain upright independent of its rotation (right?). If I look
through one half of a binocular and then turn the binocular so one tube is on
top of the other, the image through it remains upright. So it seems you
should be able to merge the two images from rotated tubes. What am I missing
here?

Bill Tschumy wrote in message m...
Has anyone here given much thought to constructing a pair of binoculars from
a pair of spotting scopes? Any links to successful or unsuccessful
projects?

I was looking at the Pentax 80mm ED spotting scope. This one was designed to
accept standard 1 1/4 eyepieces and got rave reviews on the Better View
Desired site. The ED glass gives it superb color correction.

The advantage of using spotting scopes over telescopes is that the correct
image prism system is already in place. For me, one of the main benefits of
binoculars is that you get a correctly oriented image. Bino-scopes generally
give a L-R reversed image and this would put me off.

Mounting spotting scopes side by side there would be a problem with getting
the interpupillary distance small enough. However, the Pentax spotters (as do
many others) have the eyepiece "raised" above the objective axis by the
correcting prism. So if you were to rotate the left tube clockwise and the
right tube counter clockwise, you could narrow the IPD to the degree desired.


With the Pentax I mentioned above, I've since learned that it even has a
rotating tripod adapter that allows you to rotate the scope along its optical
axis while mounted. This would allow me to angle in the eyepieces for
adjusting IPD. The only catch is whether the rotating tripod adapter is
precise enough for the system to maintain collimation when being rotated.

Collimation of the tubes could be accomplished by placing a reticle eyepiece
in each tube sequentially and aligning it similar to a finder tube.

Does this sound like a feasible idea. The Pentax ED spotter goes for around
$750 so you could get some killer binoculars for around $2000 including
eyepieces.

The Pentax 80ED has a 504mm Fl. This means with a 24 Panoptic I would get 21x
with a 3.24 degree FOV. That would be really sweet.

Why limit the idea to using fast f-ratio ED scopes? Why not make a pair
out of two Orion 80mm ED telescopes and at least have some decent
high power capability?
-Rich

On Mon, 26 Jul 2004 21:21:03 -0500, Richard wrote
(in article ) :

Bill Tschumy wrote in message
m...
Has anyone here given much thought to constructing a pair of binoculars
from
a pair of spotting scopes? Any links to successful or unsuccessful
projects?

snip

Why limit the idea to using fast f-ratio ED scopes? Why not make a pair
out of two Orion 80mm ED telescopes and at least have some decent
high power capability?
-Rich

Because I don't care that much about high power views for these. If I can
get 80x that would be more than I need. I want these for well corrected wide
field views using two eyes.

Do you even know for sure that these aren't up to the standards of The Orion
80mm. F6.3 is not all that fast. I have an F7 TEC APO that will blow the
Orion away.

Richard wrote:
Why not make a pair out of two Orion 80mm ED telescopes and at least
have some decent
high power capability?

One good reason is that higher powers require *much* better collimation.

Best,
Stephen

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Bill Tschumy wrote in message m...

Has anyone here given much thought to constructing a pair of binoculars from
a pair of spotting scopes? ...
The advantage of using spotting scopes over telescopes is that the correct
image prism system is already in place.

Erecting prisms are a standard accessory for astronomical telescopes.
I predict that if you do a cost/benefit analysis, you'll find that's
an easier and cheaper way to proceed. With spotting scopes, you pay
a lot for ruggedizing and waterproofing, neither of which is an issue
for astro use. Also, if you're planning to use these only at relatively
low power, you can undoubtedly use astro OTA's that cost a lot less
than Pentax ED spotting scopes.

- Tony Flanders

"Tony Flanders" ha scritto nel messaggio
...
Bill Tschumy wrote in message
m...

Has anyone here given much thought to constructing a pair of binoculars
from
a pair of spotting scopes? ...
The advantage of using spotting scopes over telescopes is that the
correct
image prism system is already in place.

Erecting prisms are a standard accessory for astronomical telescopes.
I predict that if you do a cost/benefit analysis, you'll find that's
an easier and cheaper way to proceed. With spotting scopes, you pay
a lot for ruggedizing and waterproofing, neither of which is an issue
for astro use. Also, if you're planning to use these only at relatively
low power, you can undoubtedly use astro OTA's that cost a lot less
than Pentax ED spotting scopes.

- Tony Flanders

Have a look on http://www.astromeccanica.it

--
--
Beta Persei
45° 35' N
08° 51' E

Remove "_nospam" to reply

On Mon, 26 Jul 2004 21:45:13 -0500, Bill Tschumy wrote
(in article ):

On Mon, 26 Jul 2004 21:21:03 -0500, Richard wrote
(in article ) :

Bill Tschumy wrote in message
m...
Has anyone here given much thought to constructing a pair of binoculars
from
a pair of spotting scopes? Any links to successful or unsuccessful
projects?

snip

Why limit the idea to using fast f-ratio ED scopes? Why not make a pair
out of two Orion 80mm ED telescopes and at least have some decent
high power capability?
-Rich

Because I don't care that much about high power views for these. If I can
get 80x that would be more than I need. I want these for well corrected wide

field views using two eyes.

Do you even know for sure that these aren't up to the standards of The Orion
80mm. F6.3 is not all that fast. I have an F7 TEC APO that will blow the
Orion away.


Oh, another reason for using spotting scopes is that they already have the
image correcting prisms installed. With binoscopes, the image is generally
left-right reversed. I consider the correct image to be a major advantage of
binoculars.

On Tue, 27 Jul 2004 07:09:56 -0500, Tony Flanders wrote
(in article ) :

Bill Tschumy wrote in message
m...

Has anyone here given much thought to constructing a pair of binoculars
from
a pair of spotting scopes? ...
The advantage of using spotting scopes over telescopes is that the correct
image prism system is already in place.

Erecting prisms are a standard accessory for astronomical telescopes.
I predict that if you do a cost/benefit analysis, you'll find that's
an easier and cheaper way to proceed. With spotting scopes, you pay
a lot for ruggedizing and waterproofing, neither of which is an issue
for astro use. Also, if you're planning to use these only at relatively
low power, you can undoubtedly use astro OTA's that cost a lot less
than Pentax ED spotting scopes.

- Tony Flanders

Tony,

But erecting prisms leave the image left-right reversed. To me this is a
major disadvantage and eliminates the "naturalness" of binoculars. If I was
content with that I'd just use a binoviewer.