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Offline Iceman

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Moon tilt illusion
« on: October 31, 2020, 04:27:29 PM »
Reading some of the back-and-forth in the sunsets in EA thread, I started getting confused about possible light ray paths from the sun to the moon then back down to an observer on earth at around sunset. In my mind, surely the high incidence angle of light hitting the moon before it begins its path toward observers on earth would have an effect on the nature and timing of moon rise and set, because the distance between the sun and moon change in FET over the course of the lunar cycle. This is argued to be the cause for the lunar phases, which makes sense, at least on its own.

This brought me to look at explanations for the lunar phases and the moon tilt illusion on the wiki. EA is invoked to explain the different apparent angle of the moon's illuminated side to the apparent position of the sun. The illuminated side of the moon consistently points up and away from the apparent position of the sun. 

What's not explained clearly (to me at least) is why the illuminated side of the moon would be pointed upward if the light that contacts the moon would, under EA hypothesis, be incident from the underside due to upward curvature of the suns rays away from earth's surface.

Thanks for any clarification.

Re: Moon tilt illusion
« Reply #1 on: October 31, 2020, 08:18:17 PM »
This was discussed at some length back in July. The Moon tilt illusion is only an optical illusion which you can test yourself in a few seconds with a ping pong ball. Since tonight is full moon (and a blue moon at that!) you will be able to try this simple experiment next week, clear skies permitting. The gist of it is, the gibbous moon's apparently wrong tilt is in fact a completely correct tilt and there is no complicated or esoteric explanation needed.

Quote
The Ping Pong Perspective

Holding a white ball at arm’s length in the direction of the Moon shows how lunar phases depend on where the Moon is in the sky with respect to the Sun. S&T: J. Kelly Beatty



The Moon's phases are actually related to orbital motion, and there's a simple and fun observation that shows how they're connected. All you'll need is a Ping-Pong ball to simulate the Moon—actually, any small, white sphere would work. Then head outside about an hour before sunset, or around the time of a first-quarter Moon. Find the Moon in the southern part of the sky, then hold the ball up at arm's length right beside it.

You'll see that the ball shows exactly the same phase as the Moon. The Sun illuminates both the ball and the Moon from the same direction, and you see them as partly sunlit and partly in shadow, their bright and dark portions mimicking each other perfectly. If the weather stays clear, you can repeat this observation on the next several afternoons. Each day the Moon's orbital motion has carried it farther east, and the sunlit portion of its disk has grown larger. If you hold your ball up near the Moon, you'll see that its “phase” has thickened too.

To sneak a preview of the Moon's appearance in the days to come, simply move the ball farther east. And if you move it all the way over so your arm points low in the eastern sky, the side of the ball that's facing you will be almost completely illuminated — nearly a “Full Ball,” so to speak. And, sure enough, a day or two before full Moon, the Moon hangs low in the eastern sky just before sunset and is almost completely illuminated.

https://skyandtelescope.org/astronomy-resources/what-are-the-phases-of-the-moon/
Once again - you assume that the centre of the video is the centre of the camera's frame. We know that this isn't the case.

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Offline Iceman

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Re: Moon tilt illusion
« Reply #2 on: October 31, 2020, 09:41:07 PM »
Nice. Yea I'd seen that applied to explain the phases of the moon - a great, simple demo.

Hoping for someone to elaborate on how they all work within EA, which I felt wasnt really explained in the wiki all that well (but again, that's just me!)