I was watching Pawn Stars and someone brought in a WWII spyglass - the single tube telescope. Does the military still use them? And what is the advantage of a spyglass vs binoculars, or vice versa?
I was in the U.S. Navy, and only used binoculars and periscopes.
The advantage of binoculars is that you can see with both of your eyes, of course. (Interestingly, you only use one eye for optical periscopes, though.) Spyglasses (terrestrial telescopes) are antiquated. However, they are probably simpler to produce than a set of binoculars.
The other advantage of binoculars is that the image is not inverted or mirrored. The funny shape of binoculars is to accomodate the double porro prisms that reflect the light in such a way to rectify the inverted image that you would get with a simple telescope.
The advantage of seeing with both of your eyes is that it’s a lot more comfortable. There is no distance perception advantage though.
Check the Wikipedia article on binoculars. It is possible to have an upright image with the appropriate lenses without a prism.
I used to have a telescope that had 10x magnification with a 25mm objective lens. It gave an upright image. It was much smaller when telescoped than 10x binoculars are. So the trade off was smaller size for narrower field of vision.
Yes, it is possible to make binoculars with erect images without prisms, but at a sacrifice in magnification and field of view. Many of the inexpensive compact binoculars do not use the porro prism scheme. They have the advantage of being compact. I have both kinds, but I rarely use the small ones.
OMG spyglasses are waaaaaaaaaaaaaay better. I use them to for my tactical wilderness training because I am soooooooo cool. They are also great for steampunk cosplay which is gives me the special nostalgic feeling.
There seems to be plenty of “spyglasses” for sale still. Search for ‘monocular’. They tend to be smaller and more rugged that binoculars, so ideal for keeping in a pocket.
Bit of a zombie thread, but I like spyglasses when they’re called spotting scopes. Here’s a brief article on the differences between binoculars and spotting scopes and when you use one versus the other.
Spotting scopes are nice when you need a bit more magnification and clarity than you can get with binoculars, you don’t have a ship to carry around the kind of optics robby cited in his post, and you don’t mind the narrow field of view tradeoff. You do need a tripod or some other form of rest for a scope though. I’ve used them for competitive shooting to see where my shots were going. For hunting, especially out West where the ranges can be fairly long, a good spotting scope makes it easier to spot game at a great distance. We had binoculars too, but the scope was great on low mirage days for trying to decipher whether that shadow on the ridge 3/4 mile away across the valley was a branch or a deer’s ear.
Pretty good when you call them telescopes too, but those tend towards largish and only semi-portable instruments.
That (4"?) navy Big Eye would be sweet for comet searching etc.
But you’d go through a ton of quarters.
Spyglasses need not be inverted either. My 18th century recreation, which I sometimes carry while reenacting gives an upright, non-reversed or inverted, image. It isn’t the greatest of optics, nor does it have great magnification, but it works. It’s also harder to stabilize than a pair of binoculars, but binoculars didn’t exist in the 1770s.
I’m guessing it’s a Galilean telescope? They do provide upright (non-inverting) images, but they have limited magnification and field of view. “Opera glasses” often use this design, especially simple small ones like these.
My brother has a collapsible brass telescope where the image is not inverted.
I have used cheap binoculars called “opera glasses” that didn’t invert the image, and didn’t have a “funny shape”. They were designed to collapse into a box the size and shape of a cigarette case.
I have found the spyglass easier to use untrained: I have a different correction for each eye, and getting binoculars adjusted so I can see properly through both eyes has eluded me to the point that I usually give up and close one eye.
I can see spyglasses offering an additional advantage that the military might find valuable: it only uses one eye.
When I was a kid playing at “war” with my friends, I would raise my toy rifle to my shoulder, then close one eye and sight through the “scope”. But as I learned more about shooting, I learned that you shouldn’t close the other eye. It takes a bit of practice, but you get to where your attention is focused entirely through the sight, but your other eye is open and you are aware of your immediate environment.
I imagine something similar can be done with a spyglass: focus your attention on the eye that is looking through the glass, but don’t become blind to what is happening 2 feet from you.
A quick search shows that spotting scopes for hunting appear to all be “monocular”. I think spotters for sniper teams use something similar, but I am not an authoritative source for that information.
Wait a second: your first-and-only post to this board was to make a sarcastic comment about a thread that’s been dead for 6 years?
Please don’t make it so difficult to comply with this board’s rule prohibiting insulting other posters.
If I was rich I’d pay to upgrade our planet’s observatory telescopes to binoculars so those poor astronomers are more comfortable. No wonder so many of them wear glasses!