Can you use a telescope for a spotting scope?

[ELR LVR]

I answered earlier that telescopes do not have erector lenses or prisms; the picture will be upside down and left to right. The principle of optics still apply: the higher the magnification the larger the required. But beyond that here are a few more things to consider:

No zoom mechanism in a telescope. Astronomers don't want the complexity of zoom lenses, and most telescopes do not have zoom lenses. They have interchangeable eyepieces with differing magnification. You swap out the eyepiece to get a different magnification. Astronomers are more interested in exact magnification with which they can make measurements and having less lenses means higher light transmission.

Horrible eye relief. Telescopes are not designed as ad-hoc terrestrial observation optics. You mount them on big-ash tripods and equatorial mounts and what not.

Telescopes are designed to be used at night looking at VERY far away places with minimal light. They will have more internal reflection and may not be well sealed.

Got it thank you
all makes sense
I study so many other things engineering, electronics and physics wise, I have not dedicated much time to study all the aspects of how Optics work, not that I can't, just not a high priority
Plus I am not a photographer by hobby
I just trust the engineers who make them to know and there is a reason you get what you pay for with a scope
I am very interested in all the aspects of how a scope works, telescope, etc and the differences
But again, my plate is kinda full studying other physics topics so ....I can wait to be a scope engineer lol
as long as my current scopes work.
I did love readin as much as possible on How Optics glass is made and things like Unertl's history
that got me interested in studying why a $3k scope is worth $3k
IE: Glass quality is akin to diamond quality, get what you pay for
Thats about as far as I am. and that Objective/ power = exit pupil diameter and the reason why a scope darkens
Mainly, I do wish someone would make a scope with an objective lense large enough to make the exit pupil the correct diameter for your eye at a high zoom power even if it were 200mm
I remember US Optics made one big hooba joob of a scope years ago, but, they declined over the years
So again thanks for your time.

 

[Turbulent Turtle]

@ELR LVR Understood. I've always been interested in optics and have had the opportunity to learn a great deal about riflescopes through my relationship with DEON, the makers of March scopes. I've also done a lot of research on my own and I discuss these things with a few dear friends. (The internet is a wonderful thing.)

I've tried to explain things as much as possible in my various posts on optics here, and other forums (fora?). I intend to continue doing so, even when some people complain some of my posts are too long; it's not a short subject.

In answer to you musing about larger objectives, the limitation is of course the size and heft of such a device. 56-60mm is quite large already. Making a good enough jump to be worthwhile means getting into the 70s, something like 72mm or 77mm. The former was used on a German scope sometime in the past, and the latter is "common" in other devices. Gor example, Kowa used to make a 77mm spotting scope.

In the olden days, prior to the advent of coatings, large objectives were de rigueur if one wanted to have useful higher magnification. You might remember the movies that showed the captain of a destroyer using humongous binoculars to scan the ocean for periscopes, icebergs, and giant squids. These binoculars had lenses that were uncoated and thus lost 5% of light transmission to reflection at each air-to-glass boundary. That added up quickly and so you needed as much light as possible to start with. I remember the coating evolution starting in the mid-70s and the effect they had when they were first introduced. The marketing went from "coated" to "multi-coated" to "fully multi-coated" meaning all air-to-glass surfaces were coated and then multi-coated.

The coating technology is what enabled high magnification riflescopes that could still be used by a single person on a rifle. The advanced multi-coating technology used on March glass allows the use of 80X on a rifle.

But there is more to understanding riflescope and how they work than just the lenses, one must also understand how the Mark 1 eyeball works and transmits the image it sees to the brain for interpretation. The afocal design of a riflescope presents a virtual image that include the objective and the reticle to the eye to be sent to the brain.

When people say all eyes are different, they are incorrect. If that were the case riflescopes would be unaffordable as they would have to be adjusted to different eyes. In fact, it should be "every brain interprets the virtual image from the riflescope differently." Which is why we have such divergent impressions from riflescope comparisons. Remember, a riflescope is an afocal device that you view with your far vision. The "diopter" adjustment is just a fine-tuning thing for the virtual image.

 

[ELR LVR]

@ELR LVR Understood. I've always been interested in optics and have had the opportunity to learn a great deal about riflescopes through my relationship with DEON, the makers of March scopes. I've also done a lot of research on my own and I discuss these things with a few dear friends. (The internet is a wonderful thing.)

I've tried to explain things as much as possible in my various posts on optics here, and other forums (fora?). I intend to continue doing so, even when some people complain some of my posts are too long; it's not a short subject.

In answer to you musing about larger objectives, the limitation is of course the size and heft of such a device. 56-60mm is quite large already. Making a good enough jump to be worthwhile means getting into the 70s, something like 72mm or 77mm. The former was used on a German scope sometime in the past, and the latter is "common" in other devices. Gor example, Kowa used to make a 77mm spotting scope.

In the olden days, prior to the advent of coatings, large objectives were de rigueur if one wanted to have useful higher magnification. You might remember the movies that showed the captain of a destroyer using humongous binoculars to scan the ocean for periscopes, icebergs, and giant squids. These binoculars had lenses that were uncoated and thus lost 5% of light transmission to reflection at each air-to-glass boundary. That added up quickly and so you needed as much light as possible to start with. I remember the coating evolution starting in the mid-70s and the effect they had when they were first introduced. The marketing went from "coated" to "multi-coated" to "fully multi-coated" meaning all air-to-glass surfaces were coated and then multi-coated.

The coating technology is what enabled high magnification riflescopes that could still be used by a single person on a rifle. The advanced multi-coating technology used on March glass allows the use of 80X on a rifle.

But there is more to understanding riflescope and how they work than just the lenses, one must also understand how the Mark 1 eyeball works and transmits the image it sees to the brain for interpretation. The afocal design of a riflescope presents a virtual image that include the objective and the reticle to the eye to be sent to the brain.

When people say all eyes are different, they are incorrect. If that were the case riflescopes would be unaffordable as they would have to be adjusted to different eyes. In fact, it should be "every brain interprets the virtual image from the riflescope differently." Which is why we have such divergent impressions from riflescope comparisons. Remember, a riflescope is an afocal device that you view with your far vision. The "diopter" adjustment is just a fine-tuning thing for the virtual image.

Thanks, I agree some subjects you just cannot summarize, and even when trying to, it still turns into a TMI type of posting
As for myself, I tend to think, TMI is better than not enough information
When I post I try to provide the important points but it at times also becomes TMI
However I figure, iut's free info so people can weed out what they dont like, read it at leisure etc.
And considering we loose about 90% of new information within 7 days....
I prefer to have TMI type info to be able to come back to.
Sometimes there is one piece of the puzzle that makes everything link together seamlessly
but such a thing may be considered common knowledge or common sense to the person expaining it
so gets left out.
Barrel harmonics are common knowledge here, so that may be left out at times when explaining to a newbie why his factory rifle is not accurate for example.
---
When I research a thing, I am always looking for that "one more piece" that makes everything click together, which can at times take years if it always gets left out. Summarized, etc.
I like the info you provide because I view it as technically correct, and not speculated assumptions of how something works, that's what we all should value here.