Obliquity calculation and valid spin angular momentums for the bodies about mercury HOT 8 CLOSED

Use NASA JPL ephemeris for that.

from mercury.

Oh that's a cool hint. unfortunately I cannot retrieve these 3 Parameters in solar masses*AU^2/day.
I've gotten:

  VX     x-component of velocity vector (AU/day)                           
  VY     y-component of velocity vector (AU/day)                           
  VZ     z-component of velocity vector (AU/day)                           
  LT     One-way down-leg Newtonian light-time (day)                       
  RG     Range; distance from coordinate center (AU)                       
  RR     Range-rate; radial velocity wrt coord. center (AU/day)            

Is there a way to do an alternative output or do I have to do some algebra?
There is the Velocity-vector, but I dont know the formular for the angular spin.

from mercury.

I don't get you. If you need in angular momentum you can just multiply position vector to velocity vector.

from mercury.

Hi,

That's the angular momentum for the orbit of the earth around the sun.
I think we need the momentum of the spin of the earth.
code:
c Calculate spin rate and longitude & inclination of spin vector
temp = sqrt(s(1)_s(1) + s(2)_s(2) + s(3)*s(3))
(s is the vector-data I need)

from mercury.

Sorry, I still can't get you. What in general do you want to calculate? The inclination of the orbit?

from mercury.

Hi,

I want to calculate the obliquity. http://en.wikipedia.org/wiki/Axial_tilt
I've got a formular - L = 2/5 m/r² * 2π/T - but it produce a scalar not a vector.

from mercury.

Hi I made a step forward I think.
The formular is L = 2/5 m * r² * 2π/T for the scalar value. Then you have to do a vector-transformation - at short (0, sin(i)|L|, cos(i)|L|). T is the time for one rotation.

That's the vector I've calculated for the earth:
0. -5.473037341070530E-15 1.262325722406288E-14

the results are good with the example-data.

thank you

from mercury.

In generally I'm not familiar with this part of astrometry. I will be on vacation next week. I ll try to think about this.

from mercury.