Talk:Naked eye

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Small Objects and Maps should be amended

I have the ability to use my eye's as a microscope unaided, at a distance of either -mm to + metres, i can see things way smaller than what can be seen with the Naked Eye, Beyond the dust and lint that floats within the fluid of the eye. If you too have this ability i would like to hear from you.. simon.rimmer@bigpond.com

Mr. Rimmer's impressive skills aside, I do think this article would benefit from the addition of additional data surrounding near objects and the limits of vision seeing small items. I know that often you hear of near-microscopic elements being "barely visible to the naked eye," and it might be interesting to list some of those things or discuss them. It would help balance the macroscopic focus of the article, perhaps. --Coppercable (talk) 19:44, 29 July 2010 (UTC)[reply]

Image added

I took the liberty of adding the picture from the "Human Eye" article. I believe it fits right in here as well

Number of stars visible

The number of stars in section Naked Eye and Astronomy has to be wrong. 2500 stars would be as far apart in the sky as a thumb's width at arm's length. Those who have spent a night at the Grand Canyon or the Rockies, know that the human eye is capable of seeing many more stars than that. It's a pity that I'm now in a light polluted city, or I'd make an estimate of the number of stars one can see. —Preceding unsigned comment added by Gwrede (talk • contribs) 08:29, 4 August 2009 (UTC)[reply]

I have seen the figure of about 6000 naked eye stars, but I don't know if that is for dark skies or not. Wschart (talk) 04:19, 27 May 2010 (UTC)[reply]

SIMBAD shows that there are about 5519 stars visible to the 6th magnitude. -- Kheider (talk) 17:15, 27 May 2010 (UTC)[reply]

Needs {copyedit} and {citations}

There's a lot of interesting stuff here. Probably much of it is correct and some of it is garbage -- but which is which? There are some really bad (non-)sentences and careless phrasing (the outstretched thumbnail? Ouch!). One really should have knowledge of the subject matter to tackle this (= my excuse for not trying to do some fixes myself). - Hordaland (talk) 13:54, 14 October 2009 (UTC)[reply]

The "distance" that the naked eye can see is pretty meaningless. Light travels forever, so long as nothing is in the way, so the "maximum distance" the human eye can see is theoretically infinite. The only limitations in this are things like the finite size of the observable universe, and brightness and angular size of the distant object in question, none of which is due to the eye. 71.104.13.132 (talk) 21:19, 7 November 2009 (UTC)[reply]

Yes and no. The most distant object that most normal people are going to see (without binoculars or a telescope) is the Andromeda Galaxy at 2.5 million light-years, which is a function of the light gathering ability of the eye. -- Kheider (talk) 16:40, 27 May 2010 (UTC)[reply]

So long as a handful of photons can hit our retina, we can process it as "light". So in that sense, sure, we can see for millions of light years. However, our ability to distinguish what an object is or how many lights there are (two headlights, or the trillion stars of Andromeda) depend on their inherent brightness and distance (we can see a candle light at 30 miles (in perfect conditions), but a galaxy of stars at greater distances). The question, "how far we can see," is incredibly dependent on the variables. That fact needs to be explained, otherwise the question is meaningless. Coinmanj (talk) 05:56, 7 June 2015 (UTC)[reply]

Environmental and Light Pollution appropriate?

I'm not sure that in its current form the information about light pollution fits this article. Unless there are some specific links to why this influences "naked eye" visualization, other than making it harder to identify certain constellations at night, then I recommend removing this section. --Coppercable (talk) 19:46, 29 July 2010 (UTC)[reply]

Harriot

See the article on Thomas Harriot. This notes that Harriot was using a telescope before Galileo. —Preceding unsigned comment added by 93.97.194.200 (talk) 12:39, 2 February 2011 (UTC)[reply]

Hello, I wanted to say that the four well known moons of jupiter can be seen by the naked eye, it's real not anecdotal, this is why I wonder why those moons weren't recognized before Gallileo. — Preceding unsigned comment added by 41.107.48.200 (talk) 12:52, 29 September 2011 (UTC)[reply]

Angular resolution

I performed a quick test yesterday evening (June 13, 2015) which, while of an inexact nature, supports the 4 arc-minute resolution referred to. The test consisted of viewing, with the naked eye, the pair of stars which together constitute the 'stinger' in the tail of Scorpius; they are Shaula (Lambda [λ] Scorpii) and Lesath (Upsilon [υ] Scorpii). These two stars are separated by just under 36 arc-minutes (source - Starry Night software) and as I looked at them, high in the sky at an altitude of ~ 70 degree, I estimated that at the limit of naked eye vision I would be able to split two stars at 1/8th of their separation - 36/8 = 4.5 arc-minutes. I intend to repeat the exercise with two closer stars, and will report the outcome here in due course. — Preceding unsigned comment added by Wgroberts (talk • contribs) 06:59, 14 June 2015 (UTC)[reply]

I'm confused about the Handbook of Statistics citation, because it contradicts the definition that normal human eyesight (20/20) means an angular resolution of one arc minute as stated not only at two other places in the article (and, originally, at the place in question, as well), but also at Visual acuity (and, indirectly, Retina Display#Criticism). If typical human eyesight were so much poorer, a human egg cell, at about 0.12 mm, could not be visible, either. Am I missing something here? --Florian Blaschke (talk) 16:07, 27 August 2013 (UTC)[reply]

Note that Visual acuity#History says the following under the year 1898:

Marius Tscherning reported the inadequacy of 20/20 (1 minute of arc) as a norm value of VA and explained the Snellen’s mistake who referred to a normal observer using this wrong value. Tscherning’s opinion is echoed by many modern investigators who have found that Snellen’s criterion does not represent the normal limits of vision. Many observers are capable of producing results that surpass the limit of the supposed 20/20 standard for visual acuity. Surprisingly, the 20/20 myth still continues today.

And under Visual acuity#Normal vision:

In humans, the maximum acuity of a healthy, emmetropic eye (and even ametropic eyes with correctors) is approximately 20/16 to 20/12, so it is inaccurate to refer to 20/20 visual acuity as "perfect" vision. (with ref)

And under Visual acuity#Expression:

It is possible to have vision superior to 20/20: the maximum acuity of the human eye without visual aids (such as binoculars) is generally thought to be around 20/10 (6/3), although recent test subjects have exceeded 20/8 vision. (with another ref)

(See also under Snellen chart for an explanation why 20/20 is actually defined as an angular resolution of precisely one arc minute: with a lower resolution, you wouldn't be able to read the E with its three limbs spaced apart by two gaps, all equally large, the whole letter appearing under five arc minutes.)

Which means that quite a lot of people actually have better eyesight than 20/20. Also, the naked eye expressly includes eyes corrected by glasses (as the intro explains), eyesight usually being corrected to the 20/20 standard. If you are trying to argue generations of ophthalmologists and optometrists have been getting this wrong, you need much better sources. --Florian Blaschke (talk) 16:33, 27 August 2013 (UTC)[reply]

The 'dubious claim' from 2003 was still there - 1 arc minute is a far more realistic as an 'average' figure so I have amended it and replaced the reference with an opthalmological rather than statistical(!) source that explains the Snelling test and also points out that some patients can exceed this '20-20' figure and hypothesises as to why this is. — Preceding unsigned comment added by Stub Mandrel (talk • contribs) 09:27, 4 August 2015 (UTC)[reply]

The "reason", as I understand it, that a person's visual acuity is referenced to 20/20 is because that is the UPPER limit of the RANGE of "normal" adult human acuity. That is, it is the limit above which (i.e. 20/21) the typical professional will recommend correction (lenses, glasses). In other words, someone with 20/18 vision will be told that they have better vision than average (or possibly than normal) when in fact their vision is worse than average. It is called pandering to your audience and doesn't do any real harm as far as I can see: most people want Yes/No answers to medical questions (such as "Am I OK?").[Note: I am unaware of any liability which might attach to some doctor claiming that someone with 20/25 or even 20/100 vision was "normal", but I would expect that at some point legal liability attaches.][Also note that despite the implication that a person's acuity is static, it is not, even ignoring aging effects (on time scales less than years)]98.21.221.175 (talk) 21:42, 29 April 2018 (UTC)[reply]

Also note that while I am extremely near-sighted (as well as significantly into my "senior" years), without my glasses my eyesight is most acute for distances of 2-4 inches. So, I think that the claims that 10" (25 cm) is normal is doubtful/questionable - there must be a range of minimal distances over which "normal" (i.e. the majority of) people are able to focus clearly on.98.21.221.175 (talk) 21:52, 29 April 2018 (UTC)[reply]

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Misleading opening definition: the naked eye is not a practice

The first paragraph states:

> Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying or light-collecting optical instrument, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is still considered "naked".

This does not seem like a correct description: it makes it sound like "naked eye" is used to refer to the practice, when it is really used in context (e.g. in "can be seen with the naked eye") to refer to the eye itself, without visual aid. Of course the distinction is a bit subtle, but I find the current description misleading. For example a more correct description would be: In astronomy, the Naked eye, also called bare eye or unaided eye, refers to the human eye unaided by a magnifying or light-collecting optical instrument, such as a telescope or microscope. The practice of engaging in visual perception without such aids may be referred to as viewing something "with the naked eye". Vision corrected to normal acuity using corrective lenses is still considered "naked". Cstanford.math (talk) 16:36, 21 July 2018 (UTC)[reply]