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2

DSCOVR is in a large Lissajous orbit around the Sun-Earth L1 point, about 1,500,000 kilometers from the Earth. At this point it is far from the line drawn between the Sun and Earth; if the Sun were behind you and you were looking at the Earth-Moon-DSCOVR system, you would say that the spacecraft is down and to the right by several hundred thousand kilometers....


10

This is a digitally enhanced composite set of images of the Moon, with successive images taken 24 hours and 40 minutes apart. There's also a long gap in time between the left half and right half of the composite. The creator of the photograph took artistic license to enlarge the Moon; she thought that that made the composite image look better. Images of the ...


8

I don't believe that this can be a simple repeated exposure of the moon. On the right, we see a thin crescent, such a moon is only possible when the moon is a couple of days old, and so must be in the West. On the left, we see an old moon, Such a moon is only visible in the very early morning, and that must be in the East, so the image must span nearly 180 ...


2

I refer to the book : Astronomical Algorithms (Second Edition) by Jean Meeus. To calculate the values of position angle of the bright limb and position angle you will need to calculate the apparent RA and DEC of the Sun and the Moon. Code the equations for the Sun RA and DEC using Chapter 25. Please note that L0 (equ. 28.2) is in error To calculate T (...


6

The key concept is called Tidal locking. Earth's gravity forced the Moon to rotate in that way during the first few tens of millions of years after the Moon formed and then kept it that way. The wikipedia page describes the mechanism: Consider a pair of co-orbiting objects, A and B. The change in rotation rate necessary to tidally lock body B to the larger ...


3

Imagine you are watching a car drive down the street from right to left (in front of a building. It goes from right to left. Now imagine watching that car with your head on your left shoulder. The car goes from the bottom of your point of view to the top. If you move your head as the car is driving past, you will see it come from the right but leave to the ...


0

Thank you to those people that have tried to help me with this, both back when I first posted the question, and later. With the solid advice of @barrycarter in the comments, I looked into using the SPICE library to compute the positions of the various celestial bodies of interest. After some reading, and further advice from NAIF themselves, I took it upon ...


8

The reason the Moon doesn't orbit the Earth's equator is to do with the Laplace plane. This is the plane around which a satellite's orbit precesses: close to the planet, the equatorial bulge is the dominant contribution to the orbital precession, so the plane matches the equatorial plane. Away from the planet, the Sun is the main contribution. The transition ...


11

In addition to what @JamesK said, I would like to point out that the statement that the moon's inclination "somehow changes over time from 18° to 28°" is rather misleading. Even if the moon orbited the Earth in a perfect circle, in exactly the same plane as the Earth orbits the Sun (known as the ecliptic plane), you would seem to see the moon ...


33

The moon is so big that the processes that circularize and reduce the equatorial inclination would take much longer. The moon is big because of how it formed: a huge collision in the early solar system. (Unlike, say the Galilean moons that probably formed along with Jupiter, or Triton, that looks like a captured TNO) The other fact that makes its orbit ...


3

If the Moon is 9 days past full, then it can't be occulting (or even at its closest approach to) Venus. Since Venus is an interior planet, it never gets far from the Sun in the sky as seen from Earth; its maximum elongation (maximum angle between Sun and Venus) is 47°. So to occult Venus, the Moon would also have to be that close to the Sun in the sky. ...


2

There are two distinct questions in your post. I'll answer the first one. There is a slight misconception in your question. A supermoon isn't just when the Moon is a periapsis, but when it is at periapsis during a full moon. Since the orbital period of the Moon is not the same as the time between two full moons, supermoons don't occur every month. (On a ...


9

The Moon's orbit about the Earth is only approximately elliptical. The Moon's orbit precesses both axially and nodally, and the eccentricity of the Moon's orbit varies. That the Moon's orbit precesses axially means that perigee sometimes occurs when the Moon is close to new, sometimes when it is close to half-full, and sometimes when it is close to full. ...


5

The moon's orbit is elliptical. This is what the moon's orbit looks like from above (A is the Earth, and C is moon, c is the orbit of the moon around the Earth) As you see with an eccentricity of 0.056 it doesn't get very close to Earth, but if you look carefully enough, there is some variation. The moon in the diagram is at apoapsis, as far from the Earth ...


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