This previously unknown event involving the Trojan asteroid (1583) Antilochus has been predicted by Isao Sato in Tokyo and forwarded to the RASNZ Occultation Section by David Dunham of IOTA. Set out below is the predicted track by Sato (not in the usual format) as well as finder charts prepared by Stephen Kerr using Guide 7 by Project Pluto.

Summary:

Sato's path crosses the extreme south-east tip of New Guinea (17:56 UTC), the tip of the Cape York Peninsula (17:56:30 UTC), the Gove Peninsula in the Northern Territory (17:56:50) and the extreme northen areas of the Kimberleys. More easterly observers may experience some interference from the coming daylight.

• Date and approx. UT time of event: December 26, 1999 @ 17:56 UT
• Magnitude of target star: 7.5
• Magnitude drop [mag]: 8.1
• Estimated maximum duration [s]: 6.2
• Path description: See above.

• Approximate width [km]: 105 km

• Name: HIP 031285 = GSC 189 1016
• Constellation: Monoceros
• J2000 position [h,m,s; ^o,',"]: 06h 33m 41.0811s; -07^o 12' 12.502"
• Position source: ACT
• V mag [mag]: 7.5
• B-V [mag]: +0.02
• The target star is in south-western Monoceros. It is 1.2^o east-south east of Beta Mon.

• Number, name: (1583) Antilochus
• Approx. diameter [km]: 102

• UT date and time of least geocentric approach: 17:56 UT
• Approx. V mag of minor planet at event [mag]: 15.6
• Magnitude drop [mag]: 8.1
• Estimated maximum duration [s]: 6.2
• Apparent motion of minor planet ["/h]: 21.5
• Angular distance to moon, phase of moon [deg,%]: 56, 79%
• Update computed by: Isao Sato

Finder Chart for Antilochus Occultation - HIP 031258

Detailed Chart for Antilichus Occultation - HIP 031258

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.