People who see *randomly* re-entering space junk (as opposed
to the Space Shuttle and a few other deliberately deorbited
objects) are *lucky*! To start with (using generalizations):

50% of re-entries occur in daylight
30% occur over land

That leaves .5 * .3 = 15%, or 6.67-to-one of a night re-entry
over land. Then beyond that:

??% occur over uninhabited land (% of land unhabited = ?)
??% occur over cloudy sky (ave. % of Earth's cloud cover = ?)
??% occur over an area when most of its inhabitants are asleep

Another factor is that due to the Earth's equatorial bulge,
the percentage re-entering over the tropics is increased (due
to more exposure to atmospheric drag).

Another factor is the number of objects in low-inclination
orbits (roughly 29 degrees from equator or less), all of which
of course re-enter in or near the tropics.

One other factor is a significant number whose perigees are
fixed in the far southern hemisphere (Molniya-type orbits,
all of which are Soviet-Russian or USA military satellites
and their launch vehicles) and which thus are most likely to
re-enter there.

The result is that it's not very likely for anyone to get to
see a random re-entry. So, if you have any reason to think
that you might have a shot at seeing one, give it a try if at
all possible! As has been mentioned, that requires knowing
about the possibility AHEAD OF TIME!

Except for the last three months when he's been otherwise
occupied with astronomical observatory tasks in Hawaii, for
some years the single best source of re-entry predictions has
been Alan Pickup:

http://www.wingar.demon.co.uk/satevo/#decayPredictions

However, as has been mentioned, the best source of last-hours
information is the SeeSat mailing list, where another re-entry
analyst, Harro Zimmer, frequently publishes predictions as
well as Alan Pickup. You don't have to subscribe to SeeSat-L;
it is archived automatically -- and well -- at this location:

http://www2.satellite.eu.org/sat/seesat/

There also is NASA's Orbital Information Group (OIG), who do
the previously mentioned Sixty Day Forecast, whose URL is
horrible -- but here's OIG's home page:

http://oig1.gsfc.nasa.gov/scripts/foxweb.exe/app01?

Go to "Main Page", "Reports", "Sixty-Day Forecast Report".

Good luck, including clear, dark nights with many fireballs!

Ed Cannon - ecannon@... - Austin, Texas, USA
http://wwwvms.utexas.edu/~ecannon/meteorlinks.html

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