Universe Sandbox
Universe Sandbox Legacy => Universe Sandbox Legacy | Help => Topic started by: cprobertson1 on July 21, 2011, 03:06:12 PM
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Hi,
Firstly, my apologies if this seems noobish; I'm afraid I'm a chemist - not a physicist and certainly the antitheses of an astrophysicist!
Long story short, when I look up something, say, for instance - the moon - using the wiki link in-simulation, it comes up with the following data:
Orbital characteristics
Perigee 362,570 km (0.0024 AU)
(356,400-370,400 km)
Apogee 405,410 km (0.0027 AU)
(404,000-406,700 km)
Semi-major axis 384,399 km (0.00257 AU)[1]
Eccentricity 0.0549[1]
Orbital period 27.321582 d (27 d 7 h 43.1 min[1])
Synodic period 29.530589 d (29 d 12 h 44 min 2.9 s)
Average orbital speed 1.022 km/s
Inclination 5.145° to the ecliptic[1]
(between 18.29° and 28.58° to Earth's equator)
Longitude of ascending node regressing by one revolution in 18.6 years
Argument of perigee progressing by one revolution in 8.85 years
Satellite of Earth
What I cant figure out is how to derive the "NODE" input for the orbital elements in the sandbox nor the argument of periapsis (although I am to understand that should change a little with time in most if not all situations)
Is there an easy way to figure out the Longitudinal Node in a case like this?
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the Argument of Periapsisafjkl or watever.
is just which way the ellipse is pointing.
ehh, i'll try an analogy.
If the outer edge of a 2-dimensional egg is the orbit of an object, then the Argument of Peri is which way the eggs is pointing.
the longitude of the ascending node (or just node)
is which way the plane is pointing. (i think)
ehhh, just stare at this diagram for a couple hours
(http://upload.wikimedia.org/wikipedia/commons/e/eb/Orbit1.svg)
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Oh. The node is where along the orbit the object goes above the plane.
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uuummm that just confused me around 5 times more than i was previously...
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Here is how I line up the moons with my planet at the equatioral plane,
Find the max "z tilt" take earth, that should go to 23.5 and then -23.5 and then 23.5 and so on.
Next to help visualize you might want to add temporary rings to help line up your node.
Now, find the max "y tilt" before it goes down and into the negatives. Type that indo the node section of the orbit of the body.
???
Planet Awesomium!
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What I cant figure out is how to derive the "NODE" input for the orbital elements in the sandbox nor the argument of periapsis (although I am to understand that should change a little with time in most if not all situations)
Is there an easy way to figure out the Longitudinal Node in a case like this?
If you're not too worried about realistic accuracy, you can't just set it to zero.
What's a situation where you're wanting to set this?