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How often is the optics of the eyes up to the quality level of the scope?

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#1 RazvanUnderStars

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Posted 24 May 2023 - 01:42 PM

Something I've meant to ask for a long time. Amateur astronomers care a lot about the optical quality of the telescopes – these forums are full of threads analyzing Strehl ratios and all that. Something I don't know is already asked in the title. What rough percentage of population has the optics of the eyes up to the par with the good telescopes?

 

Of course, some people have imperfect vision and presumably others have excellent eyes. Anecdotes aside, I'd be interested in some statistical data, if there is any. I'm not an ophthalmologist so don't have any idea.

 

Thanks for any answers.



#2 Supernova74

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Posted 24 May 2023 - 01:47 PM

I would say it varies and definitely no one answer! 



#3 ShaulaB

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Posted 24 May 2023 - 02:15 PM

Are you asking how many people who use telescopes visually are genetically endowed with superior vision? Or how many people have vision corrected well enough to make them better-than-average at telescope viewing?

 

It is well known that an experienced observer can detect more detail and see fainter objects, sometimes 2 magnitudes dimmer, than a novice can, using the same instruments. How would you factor in experience?



#4 rocco13

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Posted 24 May 2023 - 02:39 PM

Without going into a lengthy post relating all my past experiences with (and without) premium stuff, I'll just say that for my eyes, mid-level gear works plenty well. My 61-yr-old eyes are diminishing yearly so I likely won't see much difference between a $1K scope and a $4K scope.


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#5 rjacks

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Posted 24 May 2023 - 03:06 PM

Basically, if people can't see well through the eyepiece, they aren't going to take up astronomy as a hobby. The people who look through the eyepieces and like what they see, they stick with the hobby. The telescope and eyepiece are essentially filters that separate the people who see well through the eyepiece and people who don't.  



#6 t-ara-fan

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Posted 24 May 2023 - 03:15 PM

Basically, if people can't see well through the eyepiece, they aren't going to take up astronomy as a hobby.

Some might take up Astrophotography grin.gif

I have had my TOA-130 for about 2 years and only recently looked through it.  Once.
 


Edited by t-ara-fan, 24 May 2023 - 03:15 PM.

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#7 TOMDEY

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Posted 24 May 2023 - 03:52 PM

It's a very interesting... and very sensitive topic. Our bodies degrade with time. Most eyes are optimally functional in early youth... pre-teen through early teen. Then focus accommodation, acuity, wavefront, transmittence, pupil, floaters, scatter, color discrimination, etc. etc. begin to take their toll. It's so gradually degenerative that we subconsciously adapt for years or decades... before finally admitting "I need glasses" or more. Experience usually peaks long after that, which is a shame and kinda ironic. By time we know how to look... we also wistfully recall how electric vivid was the world back when we were kids, thinking that would somehow last forever.

 

Thankfully, there are many things ~modern medicine~ can provide to forestall or even correct many of these geriatric issues. Eyeglass(es) is the most obvious one. Or contact lenses, implants, PRK, Lasik. Floaters and cataracts can be eliminated; some other damages can be repaired.

 

To your point - premium telescopes and eyepieces are indeed so good now that (under most circumstances) the astronomer's eyes are the weakest link in the chain. It's like the audiophile who insists that his premium sound system (which he can finally afford) produces undistorted output covering 10 Hz to 40 kHz at 0-200 dB... even though he suffers server tinnitus (from attending too many rock concerts).

 

Annual ~full service~ checkups.    Tom

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Edited by TOMDEY, 24 May 2023 - 07:39 PM.

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#8 maroubra_boy

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Posted 24 May 2023 - 04:39 PM

Add to this equation that vision is a dynamic sense & it does change over time, more so for the worse than the better.

I for one have noticed change in my vision. I know the max diameter of my pupils has reduced & seeing M42 in full colour, greens blues & pinks, now requires shorter focal length eyepieces compared to 12 years ago & these colours are no longer as vivid to go with this. I know eventually I will no longer be able to see those soft pinks. Then for the wider population there are a multitude of reasons as to why other people cannot see the same colours I can, so vision per se is far more complicated than just black & white. There are many factors to it, many of which you may not even be aware of - did you consider colour perception for instance?

As for statistics, with the moving goal posts that vision & experience brings, as has been mentioned how is this quantifiable or the point? I can understand the curiosity around this, I really do - one of my Club members is an ophthalmologist and I have picked his brains about colour vision. Astro is a very niche application of vision, so finding astro specific stats is a hiding to nothing.

Alex

#9 Jon Isaacs

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Posted 24 May 2023 - 05:21 PM

Something I've meant to ask for a long time. Amateur astronomers care a lot about the optical quality of the telescopes – these forums are full of threads analyzing Strehl ratios and all that. Something I don't know is already asked in the title. What rough percentage of population has the optics of the eyes up to the par with the good telescopes?

 

Of course, some people have imperfect vision and presumably others have excellent eyes. Anecdotes aside, I'd be interested in some statistical data, if there is any. I'm not an ophthalmologist so don't have any idea.

 

Thanks for any answers.

 

 

Acuity of the eye is not fixed. It depends on a number of factors.

 

In the other hand, what the eye sees also depends on a number of factors.

 

The reason we use high magnifications to resolve fine details because it brings the eye closer to the image that exists at the focal plane.  It seems like increasing the magnification actually improves the image the telescope is providing but that doesn't change, we are just seeing the image in more detail because our eye is closer to the image.

 

There are a number of factors that determine what is visible by the eye, the size of objective, the quality of the objective, the brightness, size, and contrast of the object, the steadiness of the air column the telescope is looking through, the magnification.

 

In most situations, it is not the acuity of the eye nor is it the quality of the optics that limit what is seen. But there are situations, because the observer can optimize the eye's resolution by changing the magnification, that the quality of the image seen, that is the detail seen, the fine features resolved, is dependent on the quality of the telescopes optics.

 

Jon


Edited by Jon Isaacs, 24 May 2023 - 05:29 PM.

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#10 RazvanUnderStars

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Posted 24 May 2023 - 05:49 PM

Thank for the replies so far! To answer a few questions at once, I was curious abouts how many people's eyes lack the optical aberrations that we want absent (or at least smaller) in telescopes.

The telescope may produce pinpoint stars but our biological lenses may alter them (hmm... 24th century tech: a personalized deconvolver implant?).

In other words, a restated question would be: what percentage of population, looking at an image with pinpoint stars, like the one produced a telescope of sufficient quality, would see pinpoint stars without geometric and colour distortions? So less about acuity and the effects of experience (discussed many times in other threads).

There may not be studies about this, but I wanted to ask.


Edited by RazvanUnderStars, 24 May 2023 - 05:58 PM.


#11 Jon Isaacs

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Posted 24 May 2023 - 06:19 PM

 

In other words, a restated question would be: what percentage of population, looking at an image with pinpoint stars, like the one produced a telescope of sufficient quality, would see pinpoint stars without geometric and colour distortions? So less about acuity and the effects of experience (discussed many times in other threads).

 

It really does depend on the magnification. At some magnification most everyone's eye will show a star as the telescope provides it.

 

Jon



#12 dnayakan

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Posted 24 May 2023 - 06:29 PM

As pointed out, the general tendency is towards degeneracy - entropy always wins in the end. I’ve been a strongly visual person from a pretty young age and engaged in very visual pursuits through the years. So, over time, as my eyesight slowly totters into antiquity, my sensitivity, recognition and understanding of visual aspects has increased. Which has made every progressive decline a psychologically sharp ache. 

 

A lot (not all) of the decline tends to be in accommodation, and there some things like magnification can help put the image into a zone where the dilapidated eyes are at their best. I doubt that telescopes aimed at the non-scientific, non-big budget enterprises (I.e., you and me) are going to go grossly beyond what the average eye is capable of handling. They are made by firms that need to make profits and there is little market for products that promise experiences one cannot experience. Sure, we can factor in some psychological factors like bragging rights, wishful thinking (and seeing) etc. but my guess is that would be at the margins and not the median level of the market. Sort of like a (very) small number of people may buy Ferrari LaFerrari/ Musigny Grand Cru wine/substitute your high end, expensive metaphor but the Toyota Camrys will outsell them by orders of magnitude. 
 

In that sense, the eyes have always been the bottleneck - we don’t know what we don’t know till somebody does something crazy (like the Herschel’s grinding their monster mirrors) and we get to experience it. 
 

I guess it might be some salve to recognize that the visual experience is in large part an illusion generated by the brain. And it uses all kinds of nifty tricks and hacks to provide us with a coherent experience. As but one example, we all have a blind spot in the retina where the optic nerve exits the eye and heads back into the brain (thus no photoreceptors in this region). None of us has the experience of walking around with a gaping hole in our visual field and this is because the brain uses memory for the area (developed as the eye darts around in sacchades) and if you artificially restrict that, it samples the region around the blind spot and fills in the area - it makes up stuff. 
 

In fact, in some sense, all of our experience is something of an illusion. A very entertaining read is ‘Phantoms in the Brain’ by neuroscientist V S Ramchandran who documents and explains some pretty bizarre experiences that result when this system is messed up by trauma or disease. Makes you appreciate just how tenuous our experiences are.

 

Cheers, DJ


Edited by dnayakan, 24 May 2023 - 06:40 PM.

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#13 dnayakan

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Posted 24 May 2023 - 06:39 PM


There may not be studies about this, but I wanted to ask.

There have been some - usually done from a population health kind of perspective. It is hard to extrapolate from these general distributional data to individual experiences, though.

https://www.cdc.gov/...1/sr11_003.pdf 

https://www.ncbi.nlm...les/PMC8330344/

https://www.nei.nih....-and-statistics



#14 TOMDEY

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Posted 24 May 2023 - 07:57 PM

Thank for the replies so far! To answer a few questions at once, I was curious about how many people's eyes lack the optical aberrations that we want absent (or at least smaller) in telescopes.

The telescope may produce pinpoint stars but our biological lenses may alter them (hmm... 24th century tech: a personalized deconvolver implant?).

In other words, a restated question would be: what percentage of population, looking at an image with pinpoint stars, like the one produced a telescope of sufficient quality, would see pinpoint stars without geometric and colour distortions? So less about acuity and the effects of experience (discussed many times in other threads).

There may not be studies about this, but I wanted to ask.

"1980's --- Richard A. Buchroeder --- 'proportional magnification rule' ---". Reference this book here (image) >. And so much more. So yes, it has been reasonably quantified Chapter 17, p 481 etc. PS: The book is marvelous and worth ten times the list price... even ten times the current used price. I'm nearly finished reading it, hanging on its authors' every word of wisdom and experience and Soooo glad I was able to find it (used) for the bargain price of $170 US. I only found two (very minor) errata, which is in itself extraordinary.   Tom

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#15 TOMDEY

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Posted 24 May 2023 - 08:31 PM

Ehhh... before anyone asks... just in case you have the book >>>

 

Numbering of surfaces in the ~deck~.

Dummy surface 8 is slightly ~beyond~ the image plane.

typo, delete [sub-]

 

Kingslake was always correcting our errata, even miniscule grammatical ones! That grew on me... still trying to satisfy my redoubtable mentor...   Tom

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Edited by TOMDEY, 24 May 2023 - 08:38 PM.


#16 dnayakan

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Posted 24 May 2023 - 09:00 PM

Ehhh... before anyone asks... just in case you have the book >>>

 

Numbering of surfaces in the ~deck~.

Dummy surface 8 is slightly ~beyond~ the image plane.

typo, delete [sub-]

 

Kingslake was always correcting our errata, even miniscule grammatical ones! That grew on me... still trying to satisfy my redoubtable mentor...   Tom

Is the Kingslake you are referring to Rudolph Kingslake of Eastman Kodak? I am jealous if you rubbed shoulders with the man. Admired his contributions tremendously. I devoured his books on the history of photographic optics and lens design till they were tattered and dog eared…



#17 TOMDEY

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Posted 24 May 2023 - 09:55 PM

Is the Kingslake you are referring to Rudolf Kingslake of Eastman Kodak? I am jealous if you rubbed shoulders with the man. Admired his contributions tremendously. I devoured his books on the history of photographic optics and lens design till they were tattered and dog eared…

Excellent! Yes, in the strictest British tradition of ~cut the mustard~ or get out. Students both admired and feared him... good and good. I of course took and devoured his university courses. Conrady was his father in law. I loved Rudolf's wry sense of humour, and must admit, it matched my own sense, learned in iron-fisted Catholic prep schools. Students were routinely scolded and chased for (actual) laziness or inattention, and only congratulated upon notably extraordinary effort and accomplishment.  And it worked! --- our performance on standardized state and federal tests excelled, almost embarrassingly so (to others). Tom

 

"British humour carries a strong element of satire aimed at the absurdity of everyday life. Common themes include sarcasm, tongue-in-cheek, banter, insults, self-deprecation, taboo subjects, puns, innuendo, wit, and the British class system. These are often accompanied by a deadpan delivery which is present throughout the British sense of humour"

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#18 Keith Rivich

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Posted 25 May 2023 - 06:51 PM

Experience at the eyepiece will turn an aging eye back to a younger eye. With the exception of cataracts. Get this fixed as soon as possible. 


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#19 Alex Swartzinski

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Posted 25 May 2023 - 07:16 PM

. What rough percentage of population has the optics of the eyes up to the par with the good telescopes?

 

I think one of the main reasons people care about premium optics is because of control.

 

Your eyesight can't be changed for the most part, but you can control the optics of the telescope. This is also true for sky conditions. I can't remove the jet stream from making my high-power views wobbly, but I can ensure that my optics are ready for that rare night of high power.

 

I don't get too wrapped up with optics talk. My mirror is supposedly .96 Strehl. It's above diffraction limited and that's good enough for me! 

 

Premium eyepieces are much the same. Having nice glass is great for peace of mind, but the more affordable stuff works great.

 

We have lots of choices for gear these days. It's awesome that all budgets have legitimate options. 



#20 Tony Flanders

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Posted 26 May 2023 - 04:28 AM

Experience at the eyepiece will turn an aging eye back to a younger eye.


I wouldn't put it exactly like that. Given the same telescope and the same skies, I don't see nearly as much as I did twenty years ago. However, I still see a whole lot more than a newbie would, regardless how good that newbie's eyes are.


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#21 edwincjones

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Posted 26 May 2023 - 04:46 AM

as they say "a chain is only as good as its weakest link "

 

my optics have usually been better than my eyes

as I feel my eyes, and brain, needs all the help they can get.

 

I  would rather have too much quality than not enough.

 

edj


Edited by edwincjones, 26 May 2023 - 04:47 AM.

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#22 BobSoltys

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Posted 26 May 2023 - 05:28 AM

Wearing UV filtering glasses and wearing polarizing sunglasses has helped me take care of my eyes.

 

As a photographer who switched to Leica lenses for their better edge sharpness, I switched to Zeiss eyeglass lenses after a disappointing experience with trifocals from an average optical shop twenty-five years ago and I've never looked back. They're expensive but worth it.

 

Agena eyepieces' longer eye relief and wider field provided a better planetary observing experience during the maiden voyage of my new AT80EDT to view Venus and the Moon last night, and Saturn this morning.

 

Approaching seventy, I'm grateful for all the help I can get.

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#23 Keith Rivich

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Posted 26 May 2023 - 08:55 AM

I wouldn't put it exactly like that. Given the same telescope and the same skies, I don't see nearly as much as I did twenty years ago. However, I still see a whole lot more than a newbie would, regardless how good that newbie's eyes are.

I bet you you can see more at the eyepiece, same night same scope same object, then a 30 year old with little to no experience!


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#24 briansalomon1

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Posted 26 May 2023 - 09:19 AM

I've been roaming around in some very good seeing (Death Valley and western mountain ranges) with my old f8.6 TeleVue TV102 and NP101is for decades. My eyes are 20/20 now, but used to be 20/15.

 

In my experience, you might spend 100 nights out under the stars with what looks to be "pretty good" seeing, and even with 20/15 vision, only 5 of those nights will you have truly excellent seeing, and the scope will really perform.

 

I believe you need both excellent vision and a very rare night of "perfect" seeing to get full performance from excellent optics of even 4" aperture.



#25 TOMDEY

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Posted 26 May 2023 - 10:47 AM

Ideal menu:

 

>good location, dark sky, good seeing

>good visual use telescope(s) and eyepieces

>good eyewear

>ergo comfortable mount and provisions

>experience and practice

>medically maintained/refurbished eyes

 

They all matter. Most (nearly all) of us can't simultaneously optimize every one of those... but the more that we can and do... the better will be the experience. One could come up with e.g. a 0-1 impact scale for each... where the product of all six determines the goodness, zero being the hopeless limit and unity being good as it gets. And like Strehl, an 80% product would be excellent.   Tom


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