Get Orbital Elements or Positions for Eros, Mathilde, and the first four Asteroids

This page gives access to the latest orbital elements for the asteroids Mathilde and Eros, both visited by the NEAR spacecraft. It also includes the first four asteroids discovered since they are fairly easy to observe using binoculars or small telescopes. Mathilde and Eros are usually rather faint and require larger telescopes to see.

The default ephemerides give the position of the asteroid(s) each day for 20 days at 0:00 TT (nearly UT) each day. To get the default ephemerides simply click the button "Get ephemerides/summary" after making any selection to the desired objects in the section below. The summary option simply gives the current position and brightness of the selected asteroids.

Ephemerides may be generated for a specified time in the second section below.

Orbital Elements are obtained through the third section below. The returned format allows convenient entry into the selected program. For programs not listed try several formats to find one close to what is needed.

This page is a simplified version of the Minor Planet Ephemeris Service web page.

Supplementary Information

Summary

The summary lists the current J2000.0 coordinates, visual magnitude and solar elongation of the selected minor planets, as well as information on the date of last observation (where available), forthcoming opposition data and details on the latest published orbit. The opposition data lists the date of the next opposition and the declination and visual magnitude at that time.

Formats

The list of available formats for the orbital elements was correct at the time this document was prepared. It is possible that the Minor Planet Center now supports futher formats. If you select the summary option, any newly supported formats will be listed.

Elements

The elements supplied are the latest published elements for the specified objects. Elements will be found even if the designation you enter is a non-principal designation in an identification or if the object has been numbered.

Ephemerides can be supplied for objects with only Väisälä elements, but the elements themselves are not supplied.

Ephemerides

The ephemerides supplied are unperturbed. Ephemerides from perturbed orbit solutions are generated from elements at the nearest 200-day epoch. The accuracy of the ephemerides for most objects will be entirely sufficient to locate the objects for current astrometric observation. Objects must be identified in images by their motion, not by their apparent closeness to a predicted position.

The time-scale of the supplied ephemerides is strictly TT (Terrestrial Time). For practical purposes the difference between TT and UT (Universal Time), currently a little over 1 minute, may be ignored.

If you desire a topocentric ephemeris, enter your observatory code in the appropriate box. As an aide-mémoire, the packed form of the object's designation (as used on the astrometric observation record) is displayed immediately above the ephemeris.

This service utilises the Minor Planet Ephemeris Service, courtesty of the IAU's Minor Planet Center. It has been made possible by Process Software Corporation, and their excellent VMS Web server, Purveyor.