Planet's Julian Date of a point in orbit

[Philosophaie]

I would like to know the Earth Date or Julian Date of the Periapsis, Vernal Equinox or any other point in the orbit for every planet in the solar system excluding Earth.

[Janus]

Go here:

http://ssd.jpl.nasa.gov/horizons.cgi

Pick the palent you want.

change the options to give heliocentric range. Pick a date range and hit generate.

The chart will give the distance from the sun for the list of dates. Look for the date where the distance stops decreasing and starts increasing. this will be the date of periapis. (If it doesn't show up in the range of dates you used, try a new range of dates.) For instance, the next periapis for Mars falls on March 9, 2011.