1. FlightMuj

    FlightMuj Active Member

    We are discussing about the eclipse, but are flat Earth even seeing this? Even if they are seeing this I certainly believe their beliefs and "truth story" will still stay but let us just hope that I am wrong about this. Whatever the thing is, I have gained a lot of knowledge about our place in the universe and have learned about different people and their hard attitude and denial.
  2. Rory

    Rory Senior Member

    They tend to see what they want to see. I guess that's true for most of us, to varying degrees. But moreso for some. ;)
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  3. FlightMuj

    FlightMuj Active Member

    About science I will always believe what evidence will say, even if it will go against my beliefs that I have held for years, because SCIENCE IS THE TRUTH!!! Although I do come up with with my on philosophies regarding metaphysics, like is their any purpose of why we are here? What is beyond our understanding that transcends time and space? What is love, and how it descends in our thoughts, a classical example would be from Interstellar when Dr. Brand describes love and its meaning to Cooper.
    Last edited: Sep 1, 2017
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  4. Astro

    Astro Active Member

    That's awesome. I tried to get earthshine but my long exposure shots had too much internally reflected light in the telescope from the bright corona. Drat.
    You can kind of see how some of the features very faintly show up, but the scope has a characteristic blue internal reflection I've seen before with bright stars, and the corona produced it as well.

    Anyway, just to add my two cents, I did the math on the approximate path of the moon's shadow across the earth's surface, by first calculating the coordinates the shadow is projected out into space as being 180 degrees from the sun's position relative to the center of the moon. I then calculated the position of the earth's center relative to the center of the moon, and finally, the angular separation and position angle of the shadow's coordinates relative to the earth's coordinates as seen from the center of the moon. Using that information I calculated the shadow's latitude and longitude on earth by calculating the latitude and longitude of the sub lunar point and the following formulae:

    Latitude = arcsin(Sin(Moon Latitude)*cos(p)+cos(Moon Latitude)*sin(p)*cos(-theta))
    where Moon Latitude = Latitude of the sub lunar point
    p = arcsin(d/angular size of earth from moon)-d
    where d = the angular displacement of moon's shadow from center of earth as seen from the center of the moon
    theta = position angle of the displacement of the moon's shadow, with 0 degrees at north.
    Longitude = arcsin((sin(p)*sin(-theta))/cos(latitude))-moon longitude
    where moon longitude = Longitude of the sub lunar point
    latitude = latitude of the moon's shadow calculated in the first equation.

    The equations I used assumed a spherical earth, which isn't exactly true, but the result is close enough to demonstrate the general west-to-east path of the moon's shadow across the earth during the eclipse. Actually given my approximation I was pleasantly surprised by how close the resulting path was to the true path:
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  5. Great thread, I learned some cool stuff about how the moon travels I forgot or never knew. Been lurking for a few catching up on old threads.
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  6. Pedro Sequeira

    Pedro Sequeira New Member

    Hi everyone
    I saw the scale model video from the first page on youtub and it led me here

    I just wanted to share a couple of short videos I made around the last eclipse to show 2 things. The cool thing (i think) is that you can, in about 5 minutes, download the program I used, + the model, and play with it youself, speed it up or down, even change distances, make the earth spin faster, or the moon slower, or further away, etc. The instructions to download the models are in the vid descriptions

    1) why the shadow goes from west to east:

    Source: https://youtu.be/WK-ykoAsLHo

    2) why the shadow of the moon is smaller than the moon (the umbra)
    video model:

    Source: https://youtu.be/SogwFoT7f68

    real life video:

    Source: https://youtu.be/F0lSqucfFlk
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  7. Z.W. Wolf

    Z.W. Wolf Senior Member

    A new YT video. The same old mistake. The assumption is that the Moon's shadow is circling the Earth.


    The author of this video borrowed a diagram explaining geostationary satellites. To keep pace with the surface of the Earth, the geostationary satellite has to orbit the Earth faster than the surface of the Earth is rotating. The simplest way to picture this is to think of a wheel or merry-go-round. The rim rotates faster than the hub. He has extended this idea, and calculates how fast the Moon would have to move in order for the Moon's shadow to keep pace with the surface of the Earth.

    He's visualizing the line, in his diagram, from the Moon to the Earth's surface, as a fixed structure. Like a spoke on a wheel. Okay, that's fine if you want to visualize how geostationary satellites work. What he has done is calculate (accurately?) how fast the Moon would have to move to stay stationary in our sky.

    What he's not visualizing about the Moon's shadow: The Sun would also have to be orbiting the Earth; and just fast enough to keep pace with the Moon in our sky. In his diagram, the Sun would have to stay on the that same line, or spoke. But the Sun is a fixed light source. The Moon is passing in front of the Sun, and the Moon's shadow is moving across the Earth's surface; not around it.
    Last edited: Dec 29, 2018
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