June 19, 2005

Moon Illusions are coming to a sky near you this week. Look Up!
posted by peacay 19 years ago
  • This week's full moon hangs lower in the sky than any full moon since June 1987, so the Moon Illusion is going to be extra strong. That's a cool tidbit. The oscillation in the moon's position north and south is kind of interesting.
  • But unfortunately, only for you northern hemispherites. *sigh* *rugs up against winter*
  • An interesting surfing find: the Great Moon Hoax of 1835 with full text.
  • That reminds me of Orson Welles effort with War of the Worlds on radio in um...'41 or thereabouts. Good find. You shame my feeble FPP with gloriously gilded hoax padding. There's probably a 10 link FPP to the blue in that strange little escapade.
  • That wasn't a hoax. that was a brief period in time when the truth was out there, before being covered up. The fire-wielding beavers and man-bats just want you to think it was a hoax.
  • peacay - if it makes you feel any better your article led me to an hour of surfing about the moon.. thanks for adding some direction to my foggy morning!
  • What I wouldn't give for some fog now. It's too damn hot here! I'll definitely be stepping out for a gander later in the evening!
  • Time for a rousing chorus of this old favourite, methinks. All together now...
  • aww come on, if you're talking moon celebrations it's go to be Van!!
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  • Thanks for posting peacay. When I lived in North Carolina, folks there often referred to this illusion as the "Carolina Moon." In fact, I was quite moved by the very moon mentioned in your link of June '87. I was driving on a deserted road through rural NC one evening. The moon cast an eerie orange hue through breaking clouds that surrounded it. I had to stop the car and look upwards for several minutes. I incorporated the mental image of it in a painting I did later. I'll take a look upwards this week, and hope the NYC skyline doesn't obscure the show...
  • That's a nice little serendipititious story sugarmilktea. May all your illusions rise to meet you.
  • It was a frustrating discussion with my grandmother on this exact subject years ago that led me to choose to call this sort of thing a perceptual illusion as distinct from an optical illusion. Folk physics has it that this is an optical illusion, vaguely explained by the Moon's light's traversal through the atmosphere at that angle. But the illusion doesn't happen outside our heads with the light, it happens inside our heads with our visual processing. I'm inclined to think that most or all of the proposed perceptual influences are in play with this illusion...and that's why it's particularly strong. The horizon effect: visible proximity to the Earth's horizon of something distant indicates to us relatively large size. The effect of parallel lines appearing to converge as it relates to perceptual estimation of relative sizes. Also the relative size perceptual effect whereby the Moon near the horizon has others objects visually nearby to indicate great relative size--with the Moon high in the sky, alone, having the opposite effect. I also wonder if the effect isn't more pronounced when the viewer is in motion because of how we estimate distance (and therefore size) via parallax. This all brings a point to mind that I think few people understand: our vision is not equivalent to a projection on a screen nor is it equivalent to two projections on two screen with parallax. That is to say that depth perception, for example, is not merely the product of parallax (as any one-eyed person can tell you). We're sort of naive about human vision, thinking of the raw representation of shape and color and motion to be (almost, at least) its totality. But our "information extraction" with regard to these other kinds of perceptual processing makes up a much larger portion of our comprehension of what we see than we think it does. This explains why computer vision has been such a surpringly intractable problem, as well as being nicely explanatory with regard to certain inabilities to comprehend a visual field even though what we assume are all the essentials are there.
  • Perceptual v Optical is just a matter of semantics I daresay. Technically incorrect perhaps but we often know what we mean in this day and age. I don't know that it's a function of our assuming all the essentials are necessarily there as you suggest. It's more in my eyes (oh yes I demand the pun) that we have certain ocular structures which we use to varying levels of competence in relation to the materials espyed in our life such that we imprint patterns of vision or comprehension, if you will. We see, according to our limitations. In other words, I think you place too much emphasis on a concious control or perception even, whereas I think the more significant contributor is past experience. And maybe I'm quibbling with semantics too.
  • Yes, I should have emphasized experience as well. I'm not sure everyone understands the difference between what I'm calling a perceptual illusion and an optical illusion. Certainly my grandmother--who was about 60 at the time and very intelligent and educated--seemed unable to grasp the distinction. There's a good number of visual illusions that happen in the physical realm: water in the desert is the most familiar example. And, again, it's a pretty common folk explanation for the Moon illusion that it's a magnifying effect of the atmosphere at that angle of incidence.
  • Oh for sure, there's an interplay with the environment. But I think it's often true that people will not even realize that the quality of their vision is skewed as compared with the 'reality' they're exposed to. Either you have to have it explained or you have to 'see' the aberrance and understand that you are in a perception void and either move so as to increase dimensional depth or close an eye to identify a trick (that's often the case with all the 'optical' illusions we see on pc for instance -- circles of circles that appear to move and change colours -- which is just constructed so as to take advantage of the inherant rod/cone structural limitations we have). That said, I hated optical physics when I did Sci. Fortunately we could avoid one area for the exam and guess which I flicked? Heh. But this sort of thing is fun. I liked that railway effect/explanation in the link. Anyway, I'm off. It's late on the side of the world that won't *sniff* be exposed to the moon expansion and my eyes are beginning to play their own tricks on me. Cheers.
  • We lak tha mooooooon.... We REALLY lak tha moon.
  • OK, just wanted to say I saw it and it was awesome. I headed down to Battersea Bridge, and once I'd found the right sightline there it was, big and orange, with additional glowing wispy clouds. Gorgeous. Any other moon-viewing monkeys?
  • Overcast skies all week. Meh.
  • I've seen the effect before; it's not visible at my locale in this instance, however, due to a great deal of cloud.
  • I saw a brief glimpse last night through the clouds, and it was lovely!
  • I love the way light bounces from a rough white wall and this longest night, o moon I could stare at you forever riding saffron above the treetops your ribs well-sprung your bright keel skimming the ridge a battered ship still brilliant with the light of vanished sun brightface, I watch you cast your finespun silk the net that links the trees to the rooftops to the horses drinking at the stone trough to the fire and the folk around it and in a fleeting instant carry all forward across the narrows
  • and... I missed it
  • mmmmmm what a nice moon Drove back into the foothills with Mr. B and watched the moon come up three times. Everytime it would crest a hill, we'd take the truck down further, and watch it come over the next hill. Lovely effect. The air was like milk, and the moon was bright. The beer was cold. What more can you ask of life?
  • Marijuana.
  • at first she peers around the corner of the night then sidles in and growing bolder sweeps her hair back from one side then lets at last her time-briused face turn full to stare at us and what we're doing to the planet earth
  • Ach! = bruised
  • You know, in the Northern Hemisphere, it's a face, but from down here, it's a hare.
  • Hmm. by golly, she brushes her hare as I brush my collie :]
  • Hmmm, they didn't sit in an emergency ward for a couple nights, did they? I'm sure there's some bias, but talk to emergency personnel. It's amazing how many of them are convinced that things go crazy during a FM. Holidays suck, too.
  • I will, I will!! ...except it's cloudy and wet for the next three days.
  • It's too bloody cold and windy here to stand outside and watch the whole movie, but I did see the orange ball with wisps of cloud scudding across. Now it's disappeared behind the haze. Earthshadow sips At Luna's Eclips'
  • We went out at 10:30 and saw the orange moon between the clouds. It was pretty cool.