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Saturday, July 23, 2005

Solar System Live: Orbital Elements Upgrade

Building on the recent upgrade to Your Sky, Solar System Live now also supports orbital elements in the formats used by the IAU Minor Planet Center's Ephemeris Service and the DASTCOM Small-Body Orbital Elements database from the Solar System Dynamics group at JPL. This means you can plot the orbits of asteroids and comets by copying and pasting orbital elements in either of these formats into the Solar System Live request form. All orbital element formats previously supported by Solar System Live continue to work as well.

Support of JPL orbital elements means you can now look up periodic comets, asteroids by name, and asteroids by number in the Your Sky object catalogues, updated daily from the master JPL database, then cut and paste the orbital elements into Solar System Live for an Orrery view of the object's orbit. Eventually I'll add an "Orrery View" button to the Your Sky virtual telescope to automate this process.

This version of Solar System Live incorporates the Landgraf/Stumpff algorithm for near-parabolic motion from chapter 35 of Jean Meeus's Astronomical Algorithms, which permits computation of the position of comets on hyperbolic orbits with eccentricities as high as 1.1. Since no comet catalogued in the JPL database has an eccentricity higher than 1.06, this handles all bodies with well known orbits.

To demonstrate the new orbital element formats, the following links will display the orbit of the recently-clobbered comet Comet 9P/Tempel 1 with orbital elements in:

Both of these links will show the current position of the comet at the time they are clicked.

Posted at July 23, 2005 21:01