THE UPDATED PATH

This updated path lies around four path widths to the southeast of that given by Goffin and around 3 minutes later. The path passes from the northeast through the Tasman Sea without making landfall. The closest approach to the North Island of New Zealand occurs at 10:42 UT while the closest approach to Tasmania occurs at 10:44 UT.

The error margin on this calculation is fairly large with Hobart well inside the boundary. Auckland on the other hand is less likely but not out of the question.

Observers should note that the target star is quite faint - magnitude = 11.9.

Calculation Source

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

• Date and approx. UT time of event: 2001 November 22 - 10:40 UT
• Magnitude of target star: 11.9
• Magnitude drop [mag]: 4.0
• Estimated maximum duration [s]: 9.1
• Angular distance to moon, phase of moon [deg,%]: 76, 45%
• Goffin's original chart reference: A01_1141

• Approximate width [km]: 135
• Uncertainty [path widths]: +/- 1.10 (1 sigma)
• Remarks: Uncertainities are given on the basis of the nominal star position errors and the expected asteroid positional accuracy.
• Circles along the path are OCCULT calculated exact centerline points !!!!

• Name: TYC 1220-00819-1
• Constellation: Aries
• J2000 position [h,m,s; ^o,',"]: 2h 18m 33.6392s; +21^o 38' 27.271"
• Position source: UCAC + Tycho 2 Proper Motion
• Estimated accuracy ["]: 0.041" (0.030", 0.030")
• V mag [mag]: 11.8
• Remarks:
• The target star is in central Aries. It lies 1.4 degrees northeast of eta Arietis (magnitude = 5.2).

• Number, name: (1173) Anchises
• Approx. diameter [km]: 135.0
• Source of used astrometry: USNO - Flagstaff Station (Ron Stone), AstDys
• Number of used observations: 341
• Number of rejected observations: 16
• Time covered by the observations: 1930 10 17 - 2001 11 11
• 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.