I see the rising Moon
I see the high Moon

but what I don't see is why they change size. It shrinks as it climbs into the heavens, only to expand again as it sets.


Is this a real image size change, or does the mind fool us into thinking the Moon is larger or does the Moon actually shrink as it rises into less density (like a bubble) ?

LOL

A problem discussed by many, solved by few.

i am sure that you, zarkov, know what no one else knows. as usual.

:-)

zarkov
If you want to be familiar, why not just call him John?

or does the Moon actually shrink as it rises into less density (like a bubble) ?

I fail to see just how the moon beras any relation to a bubble in water.

I'm sure that I've read the answer to this optical illusion somewhere...

i was pete. i always think of him a zarkov.

the moon appears to be larger near the horizon because the atmosphere acts as a lens. the light from the moon passes through a much greater amount of atmosphere at the horizon to get to you than when it is straight above you.

>> the moon appears to be larger near the horizon because the atmosphere acts as a lens >>

Debunked, because a photograph of the rising Moon shows it really is just as large as the high Moon.

>> the moon appears to be larger near the horizon because the atmosphere acts as a lens >>

Debunked, because a photograph of the rising Moon shows it really is just as large as the high Moon.

True, the atmosphere has nothing to do with it. And it's NOT an optical illusion at all but rather a trick of the mind. It even has a name - it's called the Ponzo Illusion.

Here's a quick copy/paste about it:

"What's going on here is that your brain is interpreting the sky as being farther away near the horizon, and closer near the zenith (directly overhead). This isn't surprising; look at the sky on a cloudy day and the clouds overhead may be a few kilometers above you, but near the horizon they might be hundreds of kilometers away. The Moon, when it's on the horizon, is interpreted by your brain as being farther away. Since it's the same apparent size as when it's high up, your brain figures it must be physically bigger. Otherwise, the distance would make it look smaller. "

I don't believe that.

I don't believe that.

I don't see any indication of whom you're replying to, but if it happens to be me, look it up yourself. Simply do a Google search on "Ponzo Illusion" and you'll find credible references for it.

I think the idea that it's a brain illusion is a hoax. I can see more detail in the moon at the horizon.

>> NOT an optical illusion at all but rather a trick of the mind >>

ah ha.... we are not actually seeing what we are seeing ?

so you could be an alien with a pointed head, but I see you as a human ?

LOL

Yes I have heard that one as well.

No, the mind's eye is actually correctly interpreting what we actually see with our eyes....

I think the idea that it's a brain illusion is a hoax. I can see more detail in the moon at the horizon.

Very well, carry on. But when you finally decide to check it out, you're going to feel a little foolish. :D

You can test it by holding out your thumb and measuring the difference. I'll get back to you.

..."What's going on here is that your brain is interpreting the sky as being farther away near the horizon, and closer near the zenith (directly overhead). This isn't surprising; look at the sky on a cloudy day and the clouds overhead may be a few kilometers above you, but near the horizon they might be hundreds of kilometers away. The Moon, when it's on the horizon, is interpreted by your brain as being farther away. Since it's the same apparent size as when it's high up, your brain figures it must be physically bigger. Otherwise, the distance would make it look smaller. "I think this is almost correct for the main effect but note that you also have no way to know that the clouds at near the horizon are "hundreds of kilometers away" any more than you know the true distance to the moon. (at even less than a kilomenter all of you good depth perception (and there are many, convergence angles of the eyes, move head & paralax effects etc) fail. basically the ones you have left to judge distance with (texture {trees are smaller retinal images etc} increase haze , etc) are of lower quality.

What is able to help you form the unconscious opinion that the "sky dome" on which the moon and star appear to move at the horizon is farther away than the "dome of the sky" over head is the angular rate that clouds, birds and airplanes move and in the case of the last two, their actual size is constant.

Weeeeel, all wrong

The anomaly is due to a real optical effect

called the tele-photo effect

The image on the retnia is actually as large as your mind's eye sees it to be. So there is no illusion, the mind is not making information up.


and this can be seen to be true if you compare size of the images of a far tree when the eyes are focused on the tree and then again when the eyes are focused upon a much closer object.

The wide accomodation of the human eye allows considerable overlap in focus.

see http://www.omegafour.com/forum/viewtopic.php?t=99&sid=565c0122e2aee32bbdfe0ce73e146997

for a work in progress.

Weeeeel, all wrong

The anomaly is due to a real optical effect

called the tele-photo effect

The image on the retnia is actually as large as your mind's eye sees it to be. So there is no illusion, the mind is not making information up.


and this can be seen to be true if you compare size of the images of a far tree when the eyes are focused on the tree and then again when the eyes are focused upon a much closer object.

The wide accomodation of the human eye allows considerable overlap in focus.

see http://www.omegafour.com/forum/viewtopic.php?t=99&sid=565c0122e2aee32bbdfe0ce73e146997

for a work in progress.

Sorry, Uri, I still believe you're incorrect.

And by the way, your link doesn't seem to work.

from link
>> From reports and observation, the Moon appears larger than it really is when it is near a close horizon. When it is setting on the horizon of the ocean, it appears the correct size.

Photographic evidence clearly shows that the Moon remains the same size when high or low in the sky.

So why do people see the Moon much larger than it real is.

I have noticed that the closer the 'horizon' is the greater the illusion.

Does the mind faithfully 'see' what the eye sees ?

The clues lie in the observation that the Moon appears the correct size near a sea horizon and yet the Moon appears to grow in size the closer the local scene horizon becomes.

When the eye scans a scene in respect to distance, the mind frames the scene into something like close, short range, mid range and far away distance frames.

Objects within a distance "range" are 'squashed' into the same optical plane by the mind's eye, so the actual eye's focus is relaxed.>>>

http://www.iolky.com/spaceprogram/earthrise_as17-151-23188.jpg
http://www.iolky.com/spaceprogram/earthrise_as17-151-23188.jpg

Why is it that we can see EarthRise on moon , when fact is that from moon earth should always be seen fixed in the sky ?

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