Eccentricity

[KvickFlygarn87]

Anyone know how to calculate the eccentricity of an orbit? What will I need to know? Can I find this in KSP?

Edited November 24, 2013 by KvickFlygarn87
Minor tag failure

[Frederf]

Circle is zero, ellipse is sqrt(1 - (a/b)^2) for a long dimension, b short dimension. 1 for parabola, sqrt(1 + (a/b)^2 ) for hyperbola.

EDIT: The a/b number for orbiting is going to be R+Ap/R+Pe where R is the body radius. The twos cancel.

Edited November 24, 2013 by Frederf

[RSwordsman]

Circle is zero, ellipse is sqrt(1 - (a/b)^2) for a long dimension, b short dimension. 1 for parabola, sqrt(1 + (a/b)^2 ) for hyperbola.

EDIT: The a/b number for orbiting is going to be R+Ap/R+Pe where R is the body radius. The twos cancel.

Boom shakalaka. Orbits are just ellipses, which are mathematically defined. Info on their properties is all over the place.

[Specialist290]

To expand a bit on that thought, an orbit is an ellipse, with the center of mass of the body being orbited at one focus. To find the eccentricity of an ellipse, all you really need to know is the diameter of the planet and the periapsis and apoapsis altitudes of the orbit. By adding these together, you can find the major axis of the ellipse; divide that in half, and you have the semi-major axis.

Once you know that, you can find the distance between the center of the ellipse and one focus by subtracting the periapsis altitude and the radius of the planet (i.e. half the diameter) from the semi-major axis. Divide the result of that by the value for the semi-major axis, and you have the ellipse of the circle.

[KvickFlygarn87]

Oh, great. Thanks for the thorough answers, I appreciate that!

EDIT: I checked Wikipedia and being the dumb fool I am, I couldn't get what the crap was written.

Edited November 25, 2013 by KvickFlygarn87