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  #1  
Old 17-03-2024, 12:30 PM
refractordude
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Anyone Else Have This Problem With The Moon?

Hello there


Craters turning inside out. Is there a way to stop this? Perhaps a certain time of year or when the Moon is at a certain angle. Thanks all
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Old 17-03-2024, 03:07 PM
Dave882 (David)
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Hmm not quite sure what you meanů. Can you post an image?
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Old 17-03-2024, 06:58 PM
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GUS.K (Ivan)
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Happens more when I'm really tired, I just look away for a couple of seconds and it usually reverts back to normal. If it keeps happening, it's time to pack up. I notice it happens more frequently closer to the terminator. See 'Crater illusion' on Wikipedia.

Last edited by GUS.K; 17-03-2024 at 07:40 PM.
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Old 17-03-2024, 09:59 PM
Stefan Buda
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It is a well-known optical illusion. The brain interprets the sideways illumination as coming from the opposite direction than it really is. The easiest remedy is look at the image in a different orientation.
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Old 18-03-2024, 06:09 AM
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I have never really liked the Moon, not for that reason, but it always interfered when the sky was clear and crisp and I wanted to do some imaging.

Leon
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Old 18-03-2024, 07:07 AM
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terrible
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Old 18-03-2024, 07:09 AM
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please explain
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Old 18-03-2024, 07:18 AM
refractordude
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[QUOTE=Stefan Buda;1607575]It is a well-known optical illusion. The brain interprets the sideways illumination as coming from the opposite direction than it really is. The easiest remedy is look at the image in a different orientation.

Thanks
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Old 18-03-2024, 07:26 AM
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Ok, here's the image rotated 180 degrees.
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Old 18-03-2024, 09:28 AM
EpickCrom (Joe)
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I have only ever experienced this once so far, while observing the moon using a red wratten filter.

The effect was quite trippy!
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Old 18-03-2024, 09:49 AM
refractordude
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This is what I come up with and will try next time out observing the moon. Still learning how to respond to replies of what I post. So I am kinda all over the place.
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Old 18-03-2024, 01:23 PM
Stefan Buda
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So, have you looked at the rotated image? If yes, do you still see domes?
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Old 18-03-2024, 08:03 PM
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Echoes of my undergrad years....

this is a well known illusion.

This one is very similar.

https://youtu.be/pH9dAbPOR6M?si=aj_1zLKdEt_Ee0_G
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Old 19-03-2024, 04:52 AM
refractordude
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Stefan Buda

Thanks for all your help. The image you posted did not work at 180 degrees. I snipped another image of craters from the WWW that worked. The original image shows the crater at the 6 o'clock position which creates the illusion. When I rotated it to the 9 o'clock position the illusion does not appear. It seems the way to deal with this illusion problem is to move the telescope diagonal. What say you?
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Old 19-03-2024, 04:57 AM
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I Thank you all for your help.
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Old 19-03-2024, 08:59 AM
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Have you tried it this way?
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Old 19-03-2024, 09:53 AM
refractordude
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Stefan Buda

That second angle of your image did not work for me. The reangled image below worked. I will be out Thursday night with my scope aimed at the Moon. Will report back with findings. Thanks
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Old 22-03-2024, 12:28 PM
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Stefan Buda


Nothing like traveling to the moon with my grab and go Mead LX70 R5. Sky conditions were good for 250 mag with a 90mm aperture mask. I experienced no crater illusion at several angles. Perhaps the Moon's angle prevented the illusion. Here is the position the Moon was in during my observation.
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Old 22-03-2024, 02:24 PM
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Quote:
Originally Posted by refractordude View Post
Stefan Buda

That second angle of your image did not work for me. The reangled image below worked. I will be out Thursday night with my scope aimed at the Moon. Will report back with findings. Thanks
Interesting, but I'm curious why. Both have similar direction and angle of illumination, only the contrast is different.

Can you please have a look at the combined image and tell us if the illusion persists?
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Old 23-03-2024, 03:48 AM
refractordude
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Stefan Buda


Which two combined images and did you see a crater illusion with the two you are referring to? I am thinking crater illusion effects people differently.
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