This prediction update has been computed by Stephen Kerr based on astrometry from Ron Stone of the US Naval Observatory - Flagstaff Station. The Tycho-1 position of the target star has been used.

Summary:

This update indicates a small shift of around 0.5 of a path width to the north-west and around 2 minutes later relative to that given by Goffin. The new path runs just to the north of Mount Gambier (8:23 UT) and to the south-east of Mildura ( 8:25 UT). The path then runs near Nyngan (8:28 UT) in New South Wales before passing near Dalby (8:32 UT) and just to the south-east of Bundaberg in Queensland (8:33 UT). Brisbane lies very close to the path (8:32 UT) with the closest approach to Adelaide occurring at 8:23 UT. When consulting the map below, observers are urged to note that the circles near the ruled path are the actual path centreline - not the time graduated lines. !!

• Date and approx. UT time of event: July 14, 2000 @ 8:30 UT
• Magnitude of target star: 10.2
• Magnitude drop [mag]: 3.7
• Estimated maximum duration [s]: 29.5
• Path description: See above.
• Goffin's original chart reference: A00_0728

• Approximate width [km]: 85
• Map: See below
• Circles along the path are OCCULT calculated exact centerline points !!!!

• Name: TYC 6784-01060-1 = PPM 732518
• Constellation: Scorpius
• J2000 position [h,m,s; ^o,',"]: 16h 03m 15.264s; -25^o 08' 23.03"
• Position source: Tycho 1
• Estimated accuracy ["]: 0.07" (0.04", 0.05")
• V mag [mag]: 10.16
• B-V [mag]: +1.8
• Remarks:
• The target star is in western Scorpius. The target star lies 1.4 degrees north-east of pi Scorpii (magnitude = 2.9) and 44' due north of SAO 184068 (magnitude 5.0). The double star beta 38 (ie by S. W. Burnham - Mags = 7.4, 9.4; 4.4" at PA = 347^o) lies only 8.6' to the north-west of the target star.

• Number, name: (465) Alekto
• Approx. diameter [km]: 76.6
• Source of used astrometry: US Naval Observatory - Flagstaff Station (Ron Stone)
• Number of used observations: 39
• Number of rejected observations: 0
• Time covered by the observations: 2000 02 29 - 2000 07 02

• UT date and time of least geocentric approach: 2000 July 14, 8:40.4 UT
• Approx. V mag of minor planet at event [mag]: 13.82
• Geocentric parallax of minor planet ["]: 5.09
• Magnitude drop [mag]: 3.7
• Estimated maximum duration [s]: 29.5
• Apparent motion of minor planet ["/h]: 7.45
• Angular distance to moon, phase of moon [deg,%]: 25, 96%
• Update computed by: Stephen Kerr - Win Occult 1.2

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.