Hello from a new subscriber.

Jim Scotti (jscotti@LPL.Arizona.EDU)
Mon, 18 Dec 1995 11:16:50 -0700 (MST)

I just joined your mailing list and here's my brief (well, maybe a bit
lengthy...) "Hello" message. 

I am a Planetary Scientist at the Lunar and Planetary Laboratory at the
University of Arizona.  My job is with the Spacewatch project.  We survey
the sky looking for Near-Earth asteroids and in the process, we see a wide
variety of objects in the sky, from stars and galaxies, to asteroids and
meteors, to Earth orbiting satellites.  If you've heard about the close
approach of some little 10 meter boulder, it was most likely one of our
observing team who discovered it.  Occasionally, we find an object which
clearly has a geocentric orbit after following it for several hours.  For
us, that is a disappointment since we are hunting for chunks of rock, a
bit of an unidentified Earth orbiting satellite is not what we are after. 
One thing that we do not have at the moment is an angles only geocentric
orbit determination program.  We usually can tell if an object is on a
geocentric orbit rather than a heliocentric one by its very Earth-like
heliocentric orbit and how the residuals of the observations with that
orbit behave.  One of our discoveries that was definitely in a
heliocentric orbit made the press back at the end of 1991, but may have
been a man-made spacecraft.  That object was called 1991 VG and we
estimated that it was between 9 and 18 meters in diameter if it had a
typical asteroidal albedo. 

I have specifically imaged a man-made object in November 1992 when I was
able to observe the Galileo spacecraft as it made one of its Earth flybys
along its way to Jupiter.  As far as I know, it is the most distant
observation of a man-made object ever made.  It appeared as a stellar
object of about magnitude V=22 while the spacecraft was just over 8
million kilometers from Earth at the time.  You can see a mosaic of three
images of the spacecraft by visiting "Selected Spacewatch images" on my
home page (URL given in my signature below) or by going to


Galileo is one of the faintest images moving downward in the sequence of 3
images from left to right ending up at about 3:30 or 4:00 from the
brighter star near the center of the image. 

I've observed Earth orbiting satellites visually since I first got into
Astronomy more than 20 years ago.  I remember watching Skylab fly overhead
around Christmas time 1973 and I saw Skylab within a couple of orbits of
its re-entry in the summer of 1979.  Last month, I also caught Mir and
Atlantis in the morning a few hours after they undocked. 


Jim Scotti                                  
e-mail:     jscotti@lpl.arizona.edu
snail-mail: Lunar & Planetary Laboratory
            University of Arizona
            P.O. Box 210092
            Tucson, AZ 85721-0092 USA

Work phone: 520/621-2717
Home Page:  http://www.lpl.arizona.edu/~jscotti/