Perihelion Pass Dates for Planets - Alex's JS Orrery

[twinsen]

Hey

I am writing a basic javascript orrery which will display the position of the planets orbiting the sun. Using keplers equation I am going to find the true anomaly and the radius at the current time and then plot the points to a 2d grid.

The problem is I need to know the time that has elapsed since perihelion so I can calculate the Mean anomaly. I plan to use the iterative Newton method to get the Eccentric Anaomaly and from that work out the true anomaly.

Do you guys know where I can find a list of previous perihelion dates where the planets were at their closest approach?


Thanks
Alex

 

[russ_watters]

This obsolte/defunct, but excellent piece of shareware gives that kind of data: http://www.personalmicrocosms.com/Pages/ss_alw32.aspx

 

[D H]

The definitive source of ephemeris data is the HORIZONS system at JPL. Website: http://ssd.jpl.nasa.gov/?horizons.

 

[rewebster]

The definitive source of ephemeris data is the HORIZONS system at JPL. Website: http://ssd.jpl.nasa.gov/?horizons.

It's nice that that site still lists that we have '9 planets'.

 

[NoobixCube]

It's nice that that site still lists that we have '9 planets'.

BAH! Semantics !

 

[twinsen]

Thanks guys

Ill check out the site tommorow looks like ill have to do a bit more in depth reading onto all the different parrameters I've not really covered this stuff in my course yet but so far I see its just basic trig geometry.

Cheers

Alex