QUESTION:
DO YOU BELIEVE IT IS RESPONSIBLE FOR US TO USE OUR TELESCOPES TO VIEW 
OTHER PLANETS WHEN WE STILL DO NOT HAVE ALL OF THE POSSIBLE THREATENING 
OBJECTS SUCH AS ASTEROIDS AND COMETS CATALOGUED?

ANSWER from Forrest Hamilton on May 2, 1996
Certainly.  

Especially in the case of the HST when it was used to observe
the Shoemaker-Levy 9 impact into Jupiter.  We collected much useful data from 
the HST observations.  HST itself certainly is not the instrument of choice for
finding threatening asteroids and comets.  It's field of view is much to small 
to be useful for such work.  Ideally you would want to use a groundbased 
telescope at a very dark site that has a large field of view and very sensitive
detectors.  There are a few such programs occuring as we speak that are looking
for comets or asteroids that may hit the Earth. 
    
Using a telescope such as HST to observe other planets helps us understand
what consequences arise (energies, longevity, atmospheric affects, etc...) due
to an impact of a comet or asteroid.  With this kind of data in hand, we can
make more informed decisions as to whether it would be wise to fund programs
the would find threatening objects.

Another ANSWER from Lisa E. Sherbert on May 8, 1996
I personally believe it would be irresponsible for us to focus all 
our telescopes on one problem instead of observing, and thus learning, as 
much as we can.
     
While it is true that many people could die in the event of a major 
impact (an object over 2 Km in size) it is also true that an event of 
this size is extremely rare. There is a project which is conducting a 
survey such as you suggested: it is called Spacewatch-there is even a web 
page for it: http://xlr8.lpl.arizona.edu/spacewatch/

There is also Asteroid and Comet Impact Hazard page at URL:
	http://ccf.arc.nasa.gov/sst/main.html