At 08:06 AM 11/3/2002 -0500, you wrote:

>Where do you get astrometry at?

In its simplest form, you point a telescope at the sky, take a picure, and
then do a least-sqares plate solution on the picture and measure the
position of the object of interest. Charon does a very nice job of this.

>Is there a web site where this data is found?

Other peoples' astrometry? Not much fun in that.

For deep sky objects, astrometry is available from SIMBAD. For major
planets, astrometry is scattered throughout the literature; some
institutions, such as JPL, have collections, but not necessarily published
ones. For minor planets (which means asteroids, comets, trans-Neptunian
objects, etc), the Minor Planet Center publishes the Minor Planet Circulars
which contain observations, and which can be subscribed to for a modest
fee. Positions for important objects - typically NEO's, recently discovered
comets, and otherwise interesting objects, can be found in the Minor Planet
Electronic Circulars, which are, I believed, archived free, but are a paid
resource if you want the data hot off the presses. For supernovae, novae,
and other transient objects, astrometry is available from the IAU CBAT.
Astrometry for bright stars is available from some of the (pre-reduction)
Tycho publications. Astrometry for faint stars (typically from the PMM
engine at USNO) is unpublished, due to the volume of data generated (but
the reduced results are, obviously, published). Finally, for gamma-ray
bursters, positions are available in real-time from the GRB Coordinates
Network, run by NASA.

Last-minute occultation astrometry tends to not be published, but rather
passed around between the interested parties as the occultation approaches.


--
Jeff Medkeff
Sierra Vista, Arizona
http://www.roboticobservatory.com/jeff/