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General Astronomy >> General Observing and Astronomy

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mike174
scholastic sledgehammer

Reged: 01/04/05

Loc: Central, NJ

Seeing moon craters inside out!
#5686098 - 02/17/13 10:30 PM

Hi,

I was observing the moon and noticed that craters especially ones toward the south pole appeared inside-out like a wart on a smooth surface. I've never experienced this before. Has anyone heard of this before and can Lyme disease cause this?

I'm a bit concerned about this because it's affecting my observing and I enjoy looking at the moon more now.

Tnx,

MIke

Post Extras:

azure1961p
Postmaster

Reged: 01/17/09

Loc: USA

Re: Seeing moon craters inside out! new

[Re: mike174]
#5686198 - 02/17/13 11:38 PM

It means your not schizophrenic. Apparently the image reversal that the moon can provide this illusion doesn't occur with people having that disorder - well so I've read. It's all in perception though it would seem. Show a person a photo of the moon whose never ever seen it before - whose to say which is correct and where the illusion would fall with whom?

Pete

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Carol L

Reged: 07/05/04

Loc: Tomahawk, WI 45N//89W

Re: Seeing moon craters inside out! new

[Re: mike174]
#5686266 - 02/18/13 12:20 AM

Yeah, it's odd to see an 'outie' instead of an 'innie'.

But there's nothing to worry about, Mike - it's just an occasional optical illusion.
Sometimes it happens when we're looking at lunar images, too.

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Mike B
Starstruck

Reged: 04/06/05

Loc: shake, rattle, & roll, CA

Re: Seeing moon craters inside out! new

[Re: Carol L]
#5686375 - 02/18/13 02:40 AM

Yup, seen it too. Not recently, but i do recall the effect... it's actually kinda funny.

Then, once you get it visually back to "normal", i've tried making myself see it "reversed" again. Sometimes can do it, sometimes can't.

The trick i've found is to *blink* your eyes while viewing... sometimes this will pop things straight. That, or flit your vision across the cratered Moonscape, back-and-forth quickly... see if that resets your vision.

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mike174
scholastic sledgehammer

Reged: 01/04/05

Loc: Central, NJ

Re: Seeing moon craters inside out! new

[Re: Mike B]
#5686724 - 02/18/13 10:11 AM

Wondering if it's age related. Never did experience this until now. I think I first noticed it when watching a YouTube video of someone panning the moon.

MIke

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BigC
Carpal Tunnel

Reged: 09/29/10

Loc: SE Indiana

Re: Seeing moon craters inside out! new

[Re: mike174]
#5686764 - 02/18/13 10:41 AM

I experience that often when looking at Moon photos but not with telescope viewing.

Sometimes turning the photo upside down reverses the illusion.

There are a few lava filled craters that really are like warts just to confuse things .

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Jim Nelson
scholastic sledgehammer

Reged: 05/10/05

Loc: SE Michigan

Re: Seeing moon craters inside out! new

[Re: mike174]
#5686945 - 02/18/13 12:43 PM

Check out this picture: LINK

Wefigure out whether something in concave or convex based partially on the assumption that any light source is "up", a pretty good assumption in our daily life. All bets are out the window for astronomical photographs, where light sources may be coming from darn near any direction.

This has nothing to do with aging. I swear that in relatively close-up photographs of the moon or of Mars from orbiters, it seems like I see things the wrong way at least twice as often as the right way, and this has always been true, since childhood.

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dan777
professor emeritus

Reged: 11/16/07

Loc: Indiana

Re: Seeing moon craters inside out! new

[Re: Jim Nelson]
#5686984 - 02/18/13 02:00 PM

to add to what Jim said...
This is an optical illusion that is a result of the direction of the sun and hence direction of shadows relative to what our brain expects the shadow's direction to be. We experience this with lunar observing because the sun is not overhead relative to the moon and it therefore can create shadows that seemingly point the wrong way.

Try this experiment, the next time you experience this, change the direction you look into the eyepiece at by 180°.

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Doc Willie
Pooh-Bah

Reged: 03/31/10

Loc: Mid-Hudson Valley, NY, USA

Re: Seeing moon craters inside out! new

[Re: dan777]
#5688524 - 02/19/13 09:17 AM

I frequently see this in moon photos. One trick to get it to flip to normal is find a very small crater in the image. That will often "flip", then you gradually expand the field of view until the whole photo looks normal.

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Ed D
Carpal Tunnel

Reged: 04/30/10

Loc: Sunny South Florida

Re: Seeing moon craters inside out! new

[Re: Doc Willie]
#5690224 - 02/20/13 05:54 AM

A couple of nights ago I was observing the Lunar X and there was a crater off to the side of my view that was doing exactly that. Last evening I was looking at the same area again and it appeared totally different. The lighting can play tricks on what we see.

Ed D

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cpsTN
Carpal Tunnel

Reged: 04/26/07

Loc: Rutherford Co, TN

Re: Seeing moon craters inside out! new

[Re: Ed D]
#5690275 - 02/20/13 07:17 AM

I have seen it many times. Since I know it is not that way, if I concentrate, they will "go back in". Funny! I've seen it with street signs too. Sometimes, I see a sign and can't determine if it is facing me or angled away from me, especially if viewed from the side!

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Mark9473
Postmaster

Reged: 07/21/05

Loc: 51°N 4°E

Re: Seeing moon craters inside out! new

[Re: cpsTN]
#5690278 - 02/20/13 07:20 AM

I used to see this often, but I'm under the impression I don't ever see it when binoviewing.

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Ruimteman
member

Reged: 04/03/12

Loc: Tokyo

Re: Seeing moon craters inside out! new

[Re: Mark9473]
#5690398 - 02/20/13 09:00 AM

I'm a fan of this illusion and can often see it in photographs of craters but have never been able to see it at the eyepiece. Funny brain.

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mike174
scholastic sledgehammer

Reged: 01/04/05

Loc: Central, NJ

Re: Seeing moon craters inside out! new

[Re: Ruimteman]
#5690700 - 02/20/13 11:43 AM

It happened again the other night and while looking at a picture video. It's become a distraction now.

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kansas skies
sage

Reged: 12/02/12

Loc: Kansas, USA

Re: Seeing moon craters inside out! new

[Re: mike174]
#5690820 - 02/20/13 12:45 PM

Up until now, I've never seen this illusion. After reading about it here, I pulled up a picture of the moon and wouldn't you know, the craters were reversed. I closed my eyes for a moment, then looked again and the picture was back to normal. After that, I couldn't get it to repeat.

Bill

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rtomw77
Pooh-Bah

Reged: 10/06/04

Loc: Deer Valley, AZ

Re: Seeing moon craters inside out! new

[Re: kansas skies]
#5692120 - 02/21/13 02:11 AM

It happens to me occasionally at the scope, but I notice it more with photos.

Tom

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Unknownastron
professor emeritus

Reged: 04/06/05

Loc: CatsEye Observatory,Rural Sout...

Re: Seeing moon craters inside out! new

[Re: rtomw77]
#5692122 - 02/21/13 02:18 AM

Yes, it is a completely normal and not rare optical illusion. Kind of like the classic illusion where we are asked if we see two faces in profile facing each other or a goblet. The brain chooses one shape as the figure and the other as background. It has happened to me and does not seem to increase with age. With me, the more fatigued I am the more likely I am to see it.
Clear skies and clean glass,
Mike

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jpcannavo
professor emeritus

Reged: 02/21/05

Loc: Long Island New York

Re: Seeing moon craters inside out! new

[Re: mike174]
#5697499 - 02/23/13 10:43 PM Attachment (6 downloads)

This is in fact a very well know illusion used to illustrate aspects of visual processing. It is a consequence of our having evolved with natural light - the sun - typically coming from above. As such we tend to interpret a surface as having a raised vs. depressed region under the "processing assumption" that the lighting is from above. There are many, many references to this, simply google crater illusion. See image below to illustrate effect, and turn the screen upsidedown to reverse the effect.

Edited by jpcannavo (02/23/13 10:44 PM)

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jpcannavo
professor emeritus

Reged: 02/21/05

Loc: Long Island New York

Re: Seeing moon craters inside out! new

[Re: Jim Nelson]
#5697506 - 02/23/13 10:49 PM

Quote:

Check out this picture: LINK

Wefigure out whether something in concave or convex based partially on the assumption that any light source is "up", a pretty good assumption in our daily life. All bets are out the window for astronomical photographs, where light sources may be coming from darn near any direction.

This has nothing to do with aging. I swear that in relatively close-up photographs of the moon or of Mars from orbiters, it seems like I see things the wrong way at least twice as often as the right way, and this has always been true, since childhood.

Whoops!
Sorry about the redundant post. I didn't see this prior post by Jim.

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