links
JPL's Horizons System, the source for authoritative solar system information and ephemeris. The Horizons On-Line Solar System Data and Ephemeris Computation Service provides access to key solar system data and flexible production of highly accurate ephemerides for solar system objects (163000+ asteroids and comets, 128 natural satellites, 9 planets, the Sun, L1, L2, select spacecraft and system barycenters).
Julian Date Converter, back and forth between UT and JD.
Radial velocity fitting applet, from the University of Colorado.
Minor planet information center, information about comets and asteroids
Orbit fitting from observations, from Earth, we observe the position of a body on the sky, that is, RA and DEC. Knowing the Earth's orbit (and hence our shifting vantage) allows us to transform three positional measurments of an object on the sky into a set of orbital elements.
all that rises must converge, a non-beatmatched selection designed to fortify consumers of the otherwise 18th century content of week one - styrofoam, sigur ros, solvent, arab strap, red stars theory, 312, stars as eyes.