\documentstyle{article}
\begin{document}
\begin{center}
{\Large\bf Observation of Small Solar System Objects with Spacewatch}\\
{\sc James V. Scotti \& Robert Jedicke}\\
Lunar and Planetary Laboratory,
The University of Arizona
\end{center}

\section*{Abstract}
Since beginning an automated full-time survey for Near-Earth objects in 
September 1990, the Spacewatch project has discovered 88 new Near-Earth
asteroids (NEAs), 3 new comets, and 2 new Centaur asteroids.  
A Tektronix TK2048E CCD is used at the
$f/5$ Newtonian focus of the 0.91-m Spacewatch Telescope of the
University of Arizona on Kitt Peak.
Our Moving Object Detection
Program (MODP) is used to detect moving objects either by their
consistent motion or their trailed appearance.
MODP also identifies
the locations of Hubble Space Telescope Guide Star Catalog stars
in the image data so that automated astrometric solutions can be 
computed off-line.  Combined with automatically measured positions
of confirmed
moving objects, another program determines the astrometric solutions
and calculates the astrometric
positions for every asteroid detected.
Spacewatch typically identifies about 2000 main-belt 
asteroids each lunation while covering about 150 square degrees to a
limiting magnitude of $V_{lim} \sim 20.9$.
We report each of these measurements, usually only a single night for
main-belt asteroids, to the Minor Planet Center where known 
and multiply detected objects are identified from the astrometric list.
NEAs and other interesting objects are identified by their angular
rates of motion near opposition at the time of discovery
and are scheduled for astrometric follow-up on subsequent nights.  
Objects with exceptionally high rates of
motion, called very fast moving objects have been detected in
near real-time by the observer and followed for several hours to 
several days.  These objects are the smallest yet detected and
consolidated outside the Earth's atmosphere.  Careful analysis of
their discovery rates and orbits have indicated an enhancement of
their magnitude-frequency distribution over that anticipated before
their discovery -- of about a factor of 40 for objects near
absolute magnitude $H \sim 29$.
Additionally, a subset of these small objects which have nearly
circular orbits and perihelia near the orbit of Earth have been
recognized as having significantly different orbits from those 
of the previously known NEAs. 
Their origin is still under debate, with possible sources including
Earth or Lunar impact ejecta, Earth--Sun Trojans, or more
complicated secular resonance interactions 
of NEA orbits with the giant planets
combined with stochastic perturbational encounters with the inner 
planets.
The large volume of asteroid detections allows magnitude--frequency 
studies of the detected main-belt asteroids and Jupiter Trojans.
New discoveries of Comets and Centaur asteroids (whose orbits cross
those of the outer planets) may allow us to study their 
magnitude--frequency distributions as well.

%\end{abstract}

\end{document}
