UPDATE: 2002 JUL 23, 02:24 UT

Additional details of this and other events are available at Steve Preston's website at http://www.oz.net/~stevepr/Asteroids/asteroid.htm

• Event Rank : 98
  (The event Rank is a measure of the likelihood of observing an event. Currently, the Rank equals
  the probability of at least one successful observation by a team of two observers spaced 1/8 path
  width just inside opposite sides of the predicted path. This probability is a function of the size
  of the asteroid in the sky (in arc seconds), the uncertainty in the position of the asteroid, and
  the uncertainty in the position of the star. Eventually, the Rank will also consider factors such
  as the brightness of the star, the magnitude drop, and the duration of the event).
  
  
• Date and approx. UT time of event : 2002 Aug 22, 18:32 - 2002 Aug 22, 18:45 UT
  (Refer to map for your own location)
• Magnitude of target star : 5.9
• Magnitude drop [mag] : 7.6
• Estimated maximum duration [s] : 8.5
• Phase of moon, angular distance : 100 % sunlit, 29° distance
• Sun : 152° distance
• Rough path description : Tasmania (Australia)

• Approximate projected width [km] : 142
• Uncertainty interval [path widths] : +/- 0.35 (1 sigma)
• Uncertainty interval approx RA,DE ["] : (+/- .028 +/- .024) (1 sigma)
• Uncertainty ellipse (major, minor, PA) : ( .031", .019", 55° ) (1 sigma)
• Remarks :

• Name : HIP 117761
• Constellation : Pisces
• J2000 position [h,m,s ; °,',"]: RA: 23 52 55.5793 DE: -03 09 19.845
• Position source : Hipparcos
• Standard error : RA,DE ["]: ( .013, .008 )
• V mag [mag] : 5.9
• Remarks : (none)

• Number, name : (98) Ianthe
• Approx. diameter [km] : 104
• Approx. diameter [arcsec] : .064
• Source of used astrometry : FASTT Garradd Astdys
• Number of used observations : 275
• Number of rejected observations : 36
• Time covered by the observations : 1901 Sep 19 - 2002 Jul 21
• 1 sigma uncertainty ellipse (major, minor, PA) : 0.029, 0.018, 49°
• Remarks :
• Update computed by : Steve Preston, Medina, Washington, USA. (OrbFit).

IMPORTANT NOTE!

Astrometric updates such as these should not be taken as definitive, but rather only as an indication of where the true track may lie relative to the original predicted track. Observers must bear in mind that later astrometry, in which the target star is measured in the same field as the asteroid, may still reveal substantial changes to the predicted track and time of the event. For this reason it is most important that observers far from the predicted track still monitor the event.