Re: Observations of NEAR

Jim Scotti (jscotti@LPL.Arizona.EDU)
Tue, 20 Feb 1996 09:27:45 -0700 (MST)

On Tue, 20 Feb 1996, Jay Respler wrote:

> On Mon, 19 Feb 1996, Jim Scotti wrote:
> 
> > With the help of George Lewis at JPL, we were able to get images of the 
> > NEAR spacecraft about 15-16 hours after launch on Sunday morning using 
> > the Spacewatch telescope on Kitt Peak.  Robert Jedicke carried out the 
> > observation, getting 6 images over a bit more than half an hour.  The 
> > spacecraft and its booster appear as 2 faint trails in the images, the 
> > brighter being around V magnitude 20.0-20.5 while the fainter is about a 
> > magnitude fainter.  The spacecraft was between about 310,000 and 320,000 
> > kilometers from Earth at the time.  I have made the images available as a 
> 
> 
> Good job!  Is this a record distance for observation of a spacecraft?

Thanks.  No, my observation of the Galileo spacecraft in November, 1992 at
a distance of just over 8 million kilometers is the record as far as I
know.  Galileo was about V magnitude 22 at the time.  I have images of it
on our Spacewatch images page which can be found at URL: 

http://www.lpl.arizona.edu/spacewatch/images.html

which is pointed to from my home page as well as the Spacewatch homepage at

http://www.lpl.arizona.edu/spacewatch

We see a lot of spacejunk, but only follow up objects with rates of motion
less than about 60 degrees/day.  Some of that stuff is apparently on
geocentric orbits, but of course, we're after the Near-Earth asteroids, so
we drop the geocentric stuff as soon as we determine that it isn't in
heliocentric orbit.  I'd be interested in consolidating one or two of
those geocentric objects if we were set up to do a geocentric orbit
solution and were able to compute a search ephemeris for the next night or
later. 

I was a bit surprised at how faint NEAR was considering how bright Galileo
was - Galileo is mostly black, but it is also pretty big, while NEAR
probably was oriented with its dark solar panels aimed back towards Earth
and it is pretty small.  NEAR has an absolute magnitude about 5 magnitudes
fainter than Galileo! 

Jim.

Jim Scotti                              
Lunar & Planetary Laboratory         jscotti@lpl.arizona.edu 
University of Arizona                520/621-2717 
Tucson, AZ 85721 USA                 http://www.lpl.arizona.edu/~jscotti/