Orbital Elements, value clarification |
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Orbital Elements, value clarification |
 Oct 21 2005, 08:03 PM
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#1
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Member  Group: Members Posts: 163 Joined: 16-March 05 From: Oakville, Ontario, Canada Member No.: 201  |
ok,
not sure where to ask this but I'm a teacher who dabbles in programming and I'm writing a program to illustrate transfer orbits etc and needed the orbital elelments of the planets and found them here. I just need clarification if the "L mean longitude" tells me where the planet was on the date specified. ie earth's mean logitude is 100.5. Does that mean that earth is 100.5 degrees from the perihelion? Please say yes so I'm on the right track  or how far am I off? Any direction is appreciated cheers jb |
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Oct 21 2005, 08:25 PM
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#2
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Senior Member Group: Members Posts: 1636 Joined: 9-May 05 From: Lima, Peru Member No.: 385 |
Planetary Mean Orbits (J2000)
(epoch = J2000 = 2000 January 1.5) Planet (mean) a e i Omega ~omega L AU deg deg deg deg Mercury 0.38709893 0.20563069 7.00487 48.33167 77.45645 252.25084 Venus 0.72333199 0.00677323 3.39471 76.68069 131.53298 181.97973 Earth 1.00000011 0.01671022 0.00005 -11.26064 102.94719 100.46435 I think that L deg of Earth (100.46435) means that at the January 1, 2000, the Earth was at 100.46... degree of longitudel position around the sun. Not sure and hope someone will jump to correct this. A good source to clarify your doubts is by consult the encyclopedia: http://en.wikipedia.org/wiki/Planet Rodolfo |
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Oct 21 2005, 09:13 PM
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#3
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 Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
Som links:
NREL Solarpos documentation and source Source code and pretty good documentation for a solar position\intensity calculator. This is a compact step by step tutorial on calculating basic keplerian orbits for the planets by Paul Schlyter |
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Oct 21 2005, 10:57 PM
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#4
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Member Group: Members Posts: 163 Joined: 16-March 05 From: Oakville, Ontario, Canada Member No.: 201 |
now it makes more sense.. angle is celestial sphere angle..not sure why my brain got mixed up.. my positions don't look right with the change but it at least is a start...
need to get a overhead map of jan '00 and compare. thanks guys... |
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Oct 22 2005, 12:05 AM
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#5
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Member Group: Members Posts: 163 Joined: 16-March 05 From: Oakville, Ontario, Canada Member No.: 201 |
SUCCESS..thanks guys..turns out my rotation matrix had the -ve signs backwards.. which is why the new changes were messed up... and to think I always tell my physics students that that is the biggest error
I'm amazed how accurate it is... or appears to be lol cheers jb |
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Dec 24 2005, 09:51 AM
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#6
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Junior Member Group: Members Posts: 72 Joined: 22-December 05 Member No.: 616 |
Waaaw!
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