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THE ASTRONOMER Electronic Circular No 1642      2001 May 27 15.03UT
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise,  Basingstoke,
Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074
INTERNET: GUY@TAHQ.DEMON.CO.UK             GMH at AST.STAR.RL.AC.UK
WORLD WIDE WEB                    http://www.demon.co.uk/astronomer
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OCCULTATION OF TYC 6240 00697 by 1994 JR1
Richard Miles e-mails:
There is a very unusual event predicted for this Sunday night
(May 27/28) close to midnight, namely the occultation of a
magnitude 11 star by the TNO, 1994 JR1.  The following note was
sent recently by David Dunham of IOTA on this subject.

The chance of any single observer witnessing a positive event
(disappearance of the star) is relatively small but certainly not
zero!  The scientific value of even negative observations could be
substantial.

Do please try to observe this event, if at all possible.

Message from David Dunham:

Shortly after 0hUT on May 28, an occultation of the 11.1-mag. star
TYC 6240 00697 by the approximately 95-km Trans-Neptunian object
1994 JR1 has been predicted by Edwin Goffin to cross southern
Europe.  But since the 23rd-mag. object subtends only 0.004" and
the astrometric uncertainties are larger than the horizontal
parallax, the event could occur anywhere in Europe or Africa, or
neither if the path shifts off the Earth's surface.  But observers
throughout those continents and the Middle East are encouraged to
monitor the star located at:
RA 17h 04m 59.7s, Dec -19 deg. 11' 18" (2000).
I think there is a finder chart on the European prediction site
that you can link to from the top of the asteroidal occultation
page of the main IOTA site (http://www.lunar-occultations.com/iota)
for a possible occultation between at least 0:10 and 0:30 UT; a
central occultation should last about 4 seconds (but the size of
the object is rather uncertain - that is a main value of the
observations).
I am afraid the object is too faint to get any useful astrometric
update for the event, but now that UCAC is available, maybe someone
can try.  The nominal path crosses Europe near lat. +39, starting
in Armenia at 0:18 UT; across Turkey, near Ankara; at 0:19, over
Greece, near Athens; southern Italy; Sardinia at 0:20; then over
northern Spain.  But as noted above, the uncertainty in the path
location is greater than the Earth's radius.

Guy M Hurst