How Far Away Can You Be To See Eye Glow? Need Help

[Hammer102492]

For those that have seen "eye glow," how far away were you?

 

I'm trying to figure out something here. 

 

Thanks!

 

Hammer

[Guest JiggyPotamus]

The light reflected from the eyes of various animals can be seen a good distance away, as long as there is an unobstructed view, and there is a good angle. But I don't believe such eye shine has anything to do with sasquatch, although some people disagree. There is not really a precedent for a taptetum lucidum in primates, except for maybe some small monkeys or something. The only reason I actually entertain the idea is because I believe sasquatch to be nocturnal hunters, thus possessing a tapetum lucidum would give them superior night vision.

 

I mean imagine a human who must survive on what they can hunt at night. Our night vision is not very good, therefore it is possible that sasquatch could have developed such a structure in their eyes. But I am not yet convinced, mainly because there are other animals that people could be seeing. Eyes that appear high in the trees could be from owls, and the most common culprit for red eyeshine is likely the coyote.

 

It is just difficult to say that it is definitely a sasquatch producing the phenomenon when all you can see is the reflection from a set of eyes. Judging how large the eyes are is difficult because it is hard to know just how far away they are at night, when that is all one can see. And another huge factor is that one can misjudge the height of the eyes because they can't see the lay of the land. A coyote could be relatively close to a person, and could be standing on a piece of ground that is much higher than that the observer is standing on. So there are other possibilities for such encounters, and when there is no other evidence to support the idea that it is a sasquatch, it probably isn't.

 

I have seen some who tend to believe that the eyes themselves are emitting light, and there is definitely no precedent for such a characteristic among any mammals that I know of. So the phenomenon is probably just a reflection due to the tapetum lucidum, as even sasquatch are not going to actually emit their own light from the eye region...or from anywhere else, unless they're holding a flashlight.

But as I said, you could probably see such a reflection from a good ways off. Maybe 100 yards or so, maybe further. I cannot recall having ever seen such eyeshine over that distance, but that is probably due to the fact that there is usually not such an uninterrupted stretch of ground without trees or hills in these instances.

[BC witness]

I've seen herds of elk and deer standing in alfalfa fields at night, with the eye reflection visible out to possibly 150 yards. On a night that has some moonlight, or starshine, even their white rumps can be made out at that distance.

[Guest]

That's a fairly good question, but I can't answerit with any degree of certainty.  Eye shine could probably be seen from a considerable distance away, but if all you see is this phenemenon then how do you gauge how far away it is?

 

 

 

I have seen some who tend to believe that the eyes themselves are emitting light, and there is definitely no precedent for such a characteristic among any mammals that I know of.

 

I'm fairly certain that there isn't a single animal documented with the ability to make their eyes glow.  And it would certainly be an odd trait for a species to develop that some claim is nocturnal.

Edited February 16, 2014 by Leftfoot

[Guest Schmiml]

BC is probably right. Before our road was built up in the late 1980's, my folks house was considered 'rural'. One night, my mom caught about eye shine from our local deer's. The closest was probably about 15 feet from where we were at the window in the house. The furthest  were probably about 125 to 175 away to our north, in what was then woods (now a trailer park--oh well). The eye shine was not quite as "bright" as those standing closer, but we could definitely see them. (conditions at the time were late summer, approximately 11:30 to 11:45 pm, clear sky, almost full moon).

 

They loved the beans we grew.

[Hammer102492]

The reason I ask is because Thursday night there was some sort of light that appeared then disappeared after a few seconds. It wasn't deer eyes and I didn't have a flashlight. The top of the hill is approx 500' away from where I was standing. It was only one light. It had a warm yellow glow to it. We live in a rural area with very few light sources except for the moonlight.

So is it possible to see BF eye glow from 500' away?

[Sasfooty]

I think that it would be intentional when it was that far away. That would be "eyeshine", rather than eyeglow, which doesn't seem to be intentional. The eyeglow that I've seen was a very muted green glow, that the BF didn't seem to be aware of. Both times, they were less that 50' away. The lights that I've seen that may have been intentional eyeshine were very bright & flashed, giving the impression of being done for a purpose.

 

I've also seen the ruby red reflection when I shined a spotlight on one of them. It was brighter than the "glow", but not as bright as the "shine".

[JDL]

I don't believe that their eyes produce light.

 

With respect to the reflection of light from the eyes, it will depend on the distance of the reflected light source from the eyes, the intensity of the reflected light source, the angle at which the reflected light strikes the eyes (direct or indirect), the angle between the bigfoot's eyes and the person viewing the reflected light, and the distance between the bigfoot and he person viewing the reflected light, the wavelengths (colors) of the light source and of the reflected light.  Another factor is how much other light there is in the immediate area.  More light (extreme case daylight)  will decrease the noticeability of eye shine.

 

It will also depend on whether the bigfoot has its eyes open, eyes closed, eyes partially open, one eye opened, one eye closed, is winking a you, has a second eyelid, as some have suggested, or is blinking in an attempt to convince people that it knows Morse code.

 

The one time I have noticed what I believe to be eye shine was about six years ago at about 3 am at the Western end of I-78 North of Harrisburg, PA in an area with dairy farms.  I've told this account before, but here it is. 

 

I was traveling in the right hand lane at about 75 - 80 mph.  There was a smaller car about 200 yards ahead of me in my lane that I was overtaking and was already preparing to dim my high beams and pass.  There was no other traffic and the highway was not lit.  The other car was approaching an overpass about 100 yards beyond his position and there was a large green highway sign about ten feet before the overpass on the right side of the road.  The sign was supported by two metal posts (right one shorter, due to the slope), with the bottom edge of the sign about four and a half feet above the ground, and the top edge of the sign about nine feet above the ground.  At a distance of 300 yards I noticed that there were two very bright red reflectors mounted to the left of the sign at a height of about eight and a half feet.  The reflectors were brighter than the taillights of the car 200 yards ahead of me.  I'm an engineer, so I noticed the exceptionally bright reflectors and wondered whether they were made a special plastic, had some sort of specially refractive facets, or if it was some sort of reflective metallic coating on a sticker.  I decided to stay in the right lane as long as possible to get as close a look as possible at the reflectors before passing the car ahead of me.  I was paying more attention to the reflectors than to the car ahead of me and was overtaking it rapidly, expecting to have just enough time to change lanes and pass it right after I passed the sign with the mounted reflectors and satisfied my curiosity. 

 

For some reason, the car ahead of me slowed as it approached the sign, and as it came adjacent to the sign, it suddenly swerved halfway into the left lane, then back to the right, on the far side of the overpass, and braked, as if to stop, then began to accelerate again as the driver realized I was bearing down on him.  This all took just a few seconds, and suddenly, as you might expect, my attention was more on the erratic behavior of the driver ahead of me, than on the reflectors.  I braked to about fifty miles an hour and tracked him out of the corner of my eye as I closed the remaining 75 yards or so to the reflectors.  As I approached, I was surprised to make out portions of a silhouette below and above the sign, and to its left where the reflectors were.  Below the sign were two legs.  The left leg of the silhouette was bent to its left, my right, at the knee (which faced the highway), with the foot braced against the slope.  Its thick right leg (on the left from my perspective) was behind the thin left support post of the sign, was oriented with the knee facing the highway, and slightly bent.  The impression was that the silhouette was poised to push off the slope with its left leg and begin crossing the highway as soon as I passed.  Above the sign, was a hand, its left, grasping the sign at the palm, with the thumb behind the sign and the four fingers extending down flat against the sign crossing over the white reflective stripe that bordered the green sign.  To the left of the sign was another hand, its right, grasping the sign at the knuckles about twenty inches below the "reflectors".  The tips of the fingers of this hand were over the white reflective border stripe on that side.  The large "reflectors" were set in a large, head-like silhouette, and were clearly meant to represent large, widely spaced eyes.

 

I was about fifty feet away from it at this point and thought, "Bigfoot!?", then immediately corrected myself, thinking, "No! prank!".  I braked some more and leaned across the console to my right to get as good a look as possible at what I expected to be an elaborate two dimensional wooden cut out as I passed.  As I passed it, though, the shadowed body was clearly three dimensional, and the head and shoulders turned to look at me through the passenger's side window as I was staring back at it.  As the head on which the "reflectors" were mounted turned, the bright red reflection ended, and all I could see was a dim reflection of colorless light off of a surface with a liquid quality.

[Guest Suesquach]

Wow, JDL! This is the first time I read your sighting! Did you ever go back to the sign and check for prints?

[JDL]

No,

 

It was 3 AM, I was over five hundred miles into a 700 mile drive, and other than a cell phone camera, I didn't have anything with which to record anything I might find.  I have looked the site over from the road a few times on subsequent trips, more with an eye toward figuring out what in the area would attract a bigfoot and why it would choose that particular spot to cross the road.  As I said, there are dairy farms, but there are other spots where it could have crossed, or even passed under the road.

[NCBFr]

About 100 ft in my daughters case.  I could measure it if you need a precise answer.

[hiflier]

Hello JDL,

 

That was a very good telling of your account. Something like that should happen to everyone IMO. Even Me LOL. ESPECIALLY me. The remarkable thing was the size and intensity of the shine. And how it was reduces or non existent upon passing the sign. Interesting. I wonder if somewhere along the way eyeshine and eyeglow became synonymous. The reason being if a creature has a tapeta lucidum then eye"glow" wouldn't seem to be required. And visa versa. One would think that eye"glow" would reduce or eliminate stealth at night to a stage where the ones with plain ol' eyeshine would do away with the glow-ers by getting them at night.

 

If any were to live in caves my bet would be the bat-eating eye"glow"ers

Edited February 17, 2014 by hiflier

[Hammer102492]

Thanks for sharing that amazing story JDL!

I guess I don't really know the difference between eye shine and eye glow.

Some sort of light flashed at me for a few seconds and was gone. It was at the top of the small hill behind the house about 400' away.

I have seen deer eye shine and it was different from that.

[hiflier]

Hello Hammer102492,

It does sound as though you know the difference because you're describing two kinds of sightings. The deer and this other thing. Who's to say it is the same thing; it may not be. I guess the important thing is to understand the distinction between the two which you apparently do. And that's a good thing. There's been many debates just over definition issues so it's cool that you bring this up. Maybe there is someone around who knows more but just hasn't been here on the Forum recently. Good luck and wish I could've been more help.

Edited February 17, 2014 by hiflier

[Cotter]

Well, here's an interesting work-up of the distance you can see a firefly.  You have to make some adjustments for a BF's eye.

 

What distance is a firefly visible from?

Fireflies in Germany, by Quit007

To know how far an average person can see a firefly from, we need to know the brightness of a firefly and the minimum perceptible amount of light. We'll start with the second of those figures. Most people can see up to 6th apparent magnitudestars, and the amount of light reaching the earth's surface from such a star is 1.05 × 10-8 lux, which is lumens / m².

Consider a 100W light bulb for a moment. The output of a 100W lightbulb is 1850 lumens. The surface is a unit sphere is about 12.5 (actually 4Ï€) times its radius squared. So for a sphere with a radius of 1m, then 1m² will be the output of the source in lumens / 12.5. For the bulb this is 1850 / 12.5 = 148. Since lumens / m² is lux, you get 148 lux 1m away from a bulb. So, at what distance away from the bulb is lux 1.05 × 10-8? This will tell us how far you need to be away from a bulb to get the same apparent brightness as a 6th magnitude star.

The area of radius R sphere is 4Ï€R², so in this case we want 1850 / 4Ï€R² = 1.05 × 10-8. This rearranges to R = √(1850 / 4Ï€ × 1.05 × 10-8), which comes out as 118,409.428 which is the result in metres, so about 118km. That might seem quite a distance to be able to see a 100W lightbulb from, but remember that when the ISS astronaut lost her toolkit in orbit, that was visible in low earth orbit just from the sun reflecting off of it.

Now the output of a firefly is between 1/50 and 1/400 candlepower. The old candlepower measure is about 0.981 candela, and a candela is lumens per steradian, an angular area measurement. So (1/50) / 0.981 gives us the output of a firefly in candelas, and then multiplying that by about 12.5, since it's the same deal with a sphere, gives us 0.256 lumens for the output of a bright firefly.

We can plug this value back into our formula for the visible distance of a bulb to give us R = √(0.256 / 4π × 1.05 × 10-8), which comes out as 1,393.432m. So a bright firefly is visible from about 1393m. The formula for a dim firefly is √(0.0318 / (4π × 1.05 × 10-8)), which comes out as about 491m.

Notes

On a plane, 1 lmc = 1 cdc·rad. A full circle has a circumference of 2Ï€ radians, so a light source that uniformly radiates one circular candela (cdc) in all directions has a total luminous flux of 1 cdc·2Ï€ rad = 2Ï€ ≈ 6.28 circular lumens. Imagine a point light source with output of 1 circular candela. Then one radian of that has 1 circular lumen of flux. A surface one metre wide cutting across that angle will have 1 lux, whereas one cutting across the same angle but being two metres wide will have 1/2 lux.

Compare a straight surface to a flat surface of the same length across the radian segment. Are their average distances from the origin the same?

A candela is lumens per steradian. So a lumen is candelas * steradians. So candela is a sort of average? A candela through one radian = one lumen, but a candela through two radians = two lumens. (In circular terms,) two lumens through two radians is an average of one lumen per steradian. So the candela is an average measure in a way, dividing things down to one steradian.

Note rgb(165, 244, 1)a or rgb(112, 247, 0)b is about 550nm wavelength. There's also efg2's version, which doesn't agree with the other two. Wikipedia is tremendous on HSL and HSV.

Thanks to Doran, Mark Shoulsdon, Jeffry Archambeault, and Björn Höhrmann, for their help with this.

 

http://sbp.so/firefly