GMS@psuvm.BITNET (08/23/85)
Just in case there are some serious observers out there who are not
already aware of this -- on page 223 of the September, 1985 Sky and
Telescope magazine is an article describing the upcoming occultation
of a 6'th magnitude star by the periodic comet Giacobini-Zinner on
September 5'th at about 3:35 am EDT (7:35 UT).
This is particularly noteworthy because of the possibility that a
dense (relatively) inner coma of dust may make the apparant magnitude
of the star dim. Not much is known about the inner comas of comets (or
the rest for that matter). It is particularly important that some data
be gathered because of the upcoming close encounter of the ICE satellite
(USA - formerly ISEE-3) with the comet on September 11.
This is therefore a plea for any observers out there to grab your scopes
and set your alarms. Weather permitting, enough observations could provide
a lot of useful data regarding the densities of particles in the inner
coma. The magazine article includes finder charts and magnitudes of
comparison stars for brightness estimates.
While photoelectric measurements are important, visual observations can
be valuable also. (After all there will be only so many photoelectrically-
equipped instruments in use that night.) Enough geographically-disbursed
observations could yield a 2-d density profile similar to the profile maps
made of asteroids in similar occultations.
Ideally you should have a stopwatch (or more than one) and memorize the field
a day or two ahead of time. Any major drops in brightness could be timed
with the stopwatch and a radio capable of getting WWV (I think there is a
phone number also). Otherwise time estimates good to a few seconds and
static magnitude estimates are better than nothing.
I plan to observe if the weather is OK. The article states:
"All who carefully observe the event should immediately phone the
results to David Dunham (President of International Occultation Timing
Association)" His number is 301-585-0989. There will be a taped
message with last-minute info on the occultation in zhe days before the
event.
I am also interested in any observations.
-------------------------------------------------------------------------------
Gerry Santoro
Microcomputer Information and Support Center GMS @ PSUVM (bitnet)
Penn State University ...!psuvax1!santoro (uucp)
101 Computer Building santoro @ penn-state (csnet)
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