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Questions tagged [apparent-motion]

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Did Eudoxus describe the eclipitic on his sun motion model?

In the description of Eudoxus’s model for the sun he says one the three circles which describe solar motion is “the circle which runs along the middle of the zodiac”. Does this refer to the ecliptic ...
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What does “all stop” mean in reality?

In science fiction, when a starship captain commands "all stop," the audience simply assumes that, like a terrestrial naval ship anchored to the ocean floor, the ship literally comes to a complete ...
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What percentage of the celestial sphere can the Moon cover?

I was solving a task that said (paraphrasing): What percentage of the night sky can the Moon cover during the entire year, when observed from all points on Earth (what percentage of the night ...
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1answer
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What is the apparent rotation time for a planet relative to an other planet?

Just my curiosity. This is not my assignment etc. Let planet A take m Earth days to complete one full round around the Sun, and planet B take n Earth days for one full round around the Sun. Assuming ...
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Do other supercluster like Laniakea also get pulled by the Great Attractor?

I'm not sure, whether there is any other observable super cluster like our local one, Laniakea, and if they do exists, do they also get pulled by the Great Attractor? I am a little confused about ...
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1answer
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How to make motion of the Sun more apparent at seconds scale?

Each time I look at a shadow cast by a sunlit object it seems as if the shadow doesn't move at all. But if I look at it after say 5 minutes, I can notice that the shadow has actually moved a bit. This ...
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Are objects in the universe moving away from each other at the same acceleration?

This is a follow up question to Does the universe expand at the same rate everywhere in the universe?. If the universe is expanding, then it would seem necessary for each object (ie galaxy) to be ...
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How can one explain the apparent motion of the Sun from a heliocentric point of view?

From a horizontal frame of reference, the path of the Sun looks like a part of a circle in a tilted plane, as shown in this picture:            &...