This prediction update has been computed by Steve Kerr of Rockhampton, Queensland, Australia based on astrometry from Ron Stone of the US Naval Observatory - Flagstaff Station. The Tycho 2 position of the target star has been used.

Summary:

This updated path lies around one path width to the south of that given by Goffin and around 30 seconds later. This path is virtually identical to that given by Occult and runs from the northern outskirts of Perth in Western Australia (10:41 UT) during twilight across central South Australia and southern Queensland to the Sunshine Coast area (10:47 UT). Brisbane certainly lies within the error band of this calculation.

Observers should note that this will be a very difficult occultation to observe. The asteroid is expected to be of virtually the same brightness as the target star giving a small magnitude fall in the event of an occultation. This combined with the fact that the star is quite faint (Magnitude = 11.9) will make this observation virtually impossible for observers with smaller aperture telescopes. Should the asteroid magnitude estimate be in error and brighter than expected (quite possible depending on the rotational aspect of the asteroid), the observation may be impossible to monitor visually.

THE EVENT AT ONE GLIMPSE:

• Date and approx. UT time of event: September 11 : 10:45 UT
• Magnitude of target star: 11.93
• Magnitude drop [mag]: 0.8
• Estimated maximum duration [s]: 14.0
• Path description: See above.
• Goffin's original chart reference: A01_0926

• Approximate width [km]: 150
• Uncertainty [km]: 300 (95% confidence)
• Map: See below
• Circles along the path are OCCULT calculated exact centerline points !!!!

• Name: TYC 6854-00309-1
• Constellation: Sagittarius
• J2000 position [h,m,s; ^o,',"]: 18h 04m 10.615s; -28^o 27' 35.43"
• Position source: TYC 2
• V mag [mag]: 11.93
• Remarks:
• The target star is southwestern Sagittarius. It lies 1.1 degrees north of gamma-1 Sagittarii (magnitude = variable - 4.3 - 5.1).

• Number, name: (196) Philomela
• Approx. diameter [km]: 146
• Source of used astrometry: US Naval Observatory - Flagstaff Station (Ron Stone)
• Number of used observations: 29
• Number of rejected observations: 0
• Time covered by the observations: 2001 05 01 - 2001 08 30

• UT date and time of least geocentric approach: 2001 September 11, 10:41.6 UT
• Approx. V mag of minor planet at event [mag]: 12.05
• Geocentric parallax of minor planet ["]: 3.30
• Magnitude drop [mag]: 0.8
• Estimated maximum duration [s]: 14.0
• Apparent motion of minor planet ["/h]: 19.48
• Angular distance to moon, phase of moon [deg,%]: 173, 43%
• Update computed by: Steve Kerr, Rockhampton, Queensland Australia. (Win Occult V1.4).

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.