THE UPDATED PATH

This update consists of two paths as the target star is the double star Burnham 281 (mags = 7.5 and 9.4 - measures in 1989 - sep = 1.6", PA = 170°). As such there are two paths - one associated with each star. Given the closeness of the pair, it is unlikely that occultations of the secondary will be monitorable visually without the combined light of the primary so the magnitude drops indicated on the chart above are overall for the system. Therefore, only occultations involving the primary are practical for visual observers.

The primary path update lies around 3 path widths to the southeast of Goffin's path and around a minute later. It runs from the Hervey Bay area of Queensland (13:21 UT) to the southwest across central New South Wales and Victoria. The path brushes the western edges of metropolitan Melbourne at 13:28 UT. The error margin of this calculation is quite small but all of the Melbourne metropolitan area stand a reasonable chance of an event. Slightly further from the path, Brisbane (13:24 UT), Sydney and Canberra (13:27 UT) are still worthwhile observing locations.

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, Bill Owen of Table Moutain Observatory, California, USA and Gordon Garradd of Loomberah, New South Wales, Australia supplemented with data from the AstDys database. The Hipparcos position of the target star has been used.

• Date and approx. UT time of event: 2001 October 22: 13:25 UT
• Magnitude of target star: 7.3
• Magnitude drop [mag]: 1.9 for primary path with secondary star included.
• Estimated maximum duration [s]: 10.5
• Angular distance to moon, phase of moon [deg,%]: 80, 35%
• Goffin's original chart reference: A01_1011

• Approximate width [km]: 72
• Uncertainty [path widths]: +/- 0.57 (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: HIP 223 = PPM 143008 = SAO 108903 = Burnhams 281 (double)
• Constellation: Pisces
• J2000 position [h,m,s; ^o,',"]: 0h 02m 47.1819s; +2^o 07' 48.389"
• Position source: Hipparcos
• Estimated accuracy ["]: 0.027" (0.025", 0.011")
• V mag [mag]: 7.29
• B-V [mag]: +0.69
• Remarks:
• The target star is in central Pisces. It lies 2.4 degrees east of 25 Piscium (magnitude = 6.3)

• Number, name: (67) Asia
• Approx. diameter [km]: 60.3
• Source of used astrometry: USNO - Flagstaff Station (Ron Stone), Table Mountain Observatory (Bill Owen), Gordon Garradd, AstDys
• Number of used observations: 396
• Number of rejected observations: 54
• Time covered by the observations: 1907 11 02 - 2001 10 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.