This prediction update has been computed by Steve Preston of Medina, Washington (state) in the United States based on astrometry from Ron Stone of the US Naval Observatory - Flagstaff Station supplemented with data from the AstDys database. The Tycho 2 position of the target star has been used.

Summary:

This updated path is virtually identical to that given by Goffin and only around 10 seconds earlier. The path runs from the Southern Ocean through Bass Strait close to local sunrise (19:42 UT). The only landmass to lie within the nominal path is the far north-western tip of Tasmania and the southern tip of Wilson's Promentory. However, Melbourne lies within the error tolerance of this calculation at 19:41:30 UT. The event will occur in twilight but since the star is fairly bright, it should still be achievable in Melbourne with larger aperture telescopes. Hobart and Canberra also lie near the edge of the error band although the stronger twilight will make observation difficult at these sites.

The target star is the brighter and southern component of a wide double (60") - the two star images are merged in the predictions prepared by Edwin Goffin.

THE EVENT AT ONE GLIMPSE:

• Date and approx. UT time of event: September 16 : 19:42 UT
• Magnitude of target star: 9.19
• Magnitude drop [mag]: 2.4
• Estimated maximum duration [s]: 6.0
• Path description: See above.
• Goffin's original chart reference: A01_0909

• Approximate width [km]: 208
• Uncertainty [path widths]: 0.4 (1 sigma)
• Map: See below
• Circles along the path are OCCULT calculated exact centerline points !!!!

• Name: TYC 1311-03007-1 = PPM 94783 = SAO 77489
• Constellation: Taurus
• J2000 position [h,m,s; ^o,',"]: 5h 44m 41.7348s; +20^o 42' 12.336"
• Position source: TYC 2
• Estimated accuracy ["]: 0.033" (0.022", 0.025")
• V mag [mag]: 9.19
• B-V [mag]: +0.54
• Remarks:
• The target star is southeastern Taurus. It lies 1.7 degrees east-southeast of zeta Tauri (magnitude = 3.0).

• Number, name: (40) Harmonia
• Approx. diameter [km]: 111
• Source of used astrometry: US Naval Observatory - Flagstaff Station (Ron Stone), AstDys
• Number of used observations: 3376
• Number of rejected observations: 184
• Time covered by the observations: 1914 03 30 - 2000 11 02

• UT date and time of least geocentric approach: 2001 September 16, 19:42.6 UT
• Approx. V mag of minor planet at event [mag]: 11.44
• Geocentric parallax of minor planet ["]: 4.39
• Magnitude drop [mag]: 2.4
• Estimated maximum duration [s]: 6.0
• Apparent motion of minor planet ["/h]: 45.74
• Angular distance to moon, phase of moon [deg,%]: 79, 1%
• 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.