What do we call these points?

  • Thread starter Eagle9
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  • #1
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Good day!
On the image depicted below you see the Earth and Space Elevator, both they are tilted to plane of ecliptic at 23 degrees. The plane of ecliptic is shown as dark-green circle, Earth’s equator-grey ring and big red ring is the imaginary path drawn by the Space Elevator’s counterweight (there is inscription “Space Elevator”) at the certain altitude.

You can also see four yellow balls placed at that red ring. They are placed at some certain point of the ring, more precisely balls 0 and 180 are placed at this ring and at the plane of ecliptic at the same time, in other words they are placed exactly at the points where the red ring crosses plane of ecliptic (this can happen only at two places). Ball 90 is placed at the point where the red ring occupies the highest position in space (relative to the plane of ecliptic), ball 270-the lowest position.

I would like to know this: when I write that the Earth (with the Space Elevator) rotates around its axis the counterweight reaches these four point during 24 hours, so what do we call these points/balls? What can I write in my paper when I want to state that the counterweight reached on of these points? As far as I know balls 0 and 180 are called orbital nodes (http://en.wikipedia.org/wiki/Orbital_node), what about the points 90 and 270? :)
http://img692.imageshack.us/img692/6884/15237974.jpg [Broken]
 
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Answers and Replies

  • #2
phyzguy
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The 0 and 180 points are in fact called the orbital nodes - 0 would be the ascending node and 180 the descending node. If the other two have formal names, I have not been able to find them. I have sometimes heard them referred to as the point of maximum elevation and the point of maximum depression.
 
  • #3
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The 0 and 180 points are in fact called the orbital nodes - 0 would be the ascending node and 180 the descending node. If the other two have formal names, I have not been able to find them. I have sometimes heard them referred to as the point of maximum elevation and the point of maximum depression.

Maximum elevation
Maximum depression
It’s interesting :wink: I tried to find some information about these terms (regarding astronomy) in Wikipedia, Google but I could not, could you please tell me where did you hear/see about them?
 
  • #4
phyzguy
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No, I don't have a reference. That was just from memory and may not be accurate. But I'm sure about the other two (ascending and descending nodes).
 
  • #5
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No, I don't have a reference. That was just from memory and may not be accurate. But I'm sure about the other two (ascending and descending nodes).

Me too, but I would like to be sure regarding points 90 and 270 :wink:
 
  • #6
237
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What do other people in this forum say about this? Do you think that it would be OK if in my paper I write something like this: “When the Space Elevator’s counterweight reaches Maximum elevation/depression……………..” :smile:
 

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