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Old 28-12-2014, 01:12 AM
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JB80 (Jarrod)
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The Dome Illusion!

Perspective can be a funny old thing at times and coupled with the way our brains interpret what it is seeing it can make for some really interesting optical illusions. One such illusion on the lunar surface that to my eyes and hopefully yours too I have captured in the image below occurs when the sunlight seemingly strikes the moon from below causing the shadows of the craters to extend upwards. We have a difficult time interpreting this view as our brains are used to seeing a more normal view of things so it auto-corrects the image you see so what are craters and valleys on the lunar surface appear like domes and mountain ridges.
It's a rather cool effect and gives a certain 3D pop to the image.

Hopefully you can see this easy enough and if you are having trouble just look at the top image and relax, use a kind of blank stare and once you see it it will be like a switch has been turned on. There will be domes, mountains and little ball like structures all over.
I find that looking at the valley and crater in the central part of the picture(Vallis & Crater Rheita) for about 10 seconds and then trying to look out of the corner of my eye to the other largeish crater on the right hand edge(Crater Stevinus) flips the switch.

The last image is the view corrected by flipping 180 which should normalise the view.

Hope it works for you!
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Old 28-12-2014, 08:02 AM

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Although I have often had this happen to me, these images all seem correct to me no matter how long I look. I have previously been able to 'flip the switch' by just blinking, maybe my brain is still under the influence of chocolates from Christmas. Thanks for posting these Jarrod.
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Old 28-12-2014, 08:55 AM
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csb (Craig)
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Great. I always find once I see the inverted craters then it is difficult to get the correct view back.
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Old 28-12-2014, 12:44 PM
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michaellxv (Michael)
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I have seen this effect at the eye piece and even though I know better find it hard flick the switch to get the correct image in my brain. I don't think I have ever noticed it in an image and I don't see it in yours either.
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Old 29-12-2014, 12:27 AM
cjb (Chris)
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Very cool - I can definitely get the inverted image in the first one by letting my eyes go "fuzzy" - I've never seen this at the eyepiece but I often see this effect when looking at moon images on glossy paper - i.e. magazines and books

Thanks for posting

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Old 30-12-2014, 01:15 AM
Star Catcher (Ted Dobosz)
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Good stuff Jarrod. I get caught out with inversions, particularly when the shadows are short.
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