This prediction update has been computed by Jan Manek based on astrometry from Ron Stone of the US Navel Observatory - Flagstaff Station, Bill Owen of TMO and the Hipparcos astrometric satellite mission. The Hipparcos position of the target star has been used.

Summary:

This update indicates a path shift to the south with virtually no change in time relative to that given by Goffin. The path crosses the southern New South Wales coast around Ulladulla (17:52:45 UT - target star altitude = 23°). The path runs just to the south of Canberra, including the towns of Albury, Wangaratta and Bendigo. The path runs just to the north of Melbourne (17:53:10 UT - target star altitude = 27°). The path then crosses the South Australian coastline to the north of Millicent (17:53:30 UT - target star altitude = 31°). The path now misses the southern coast of Western Australia (17:55:45 UT) though is still quite close and well worth monitoring.

Note that with an expected magnitude of 10.2, observers can expect to be able to see the asteroid. In this case, an occultation will appear as a dimming rather than a disapperence of the star. Careful attention is therefore required to monitor this event (see note below about nearby star). Observations made by non-visual techniques (eg. video) are most welcome.

With the very extensive set of astrometry used in this calculation, the path uncertainty for this event is only 0.55 of a path width. Consequently, an organised program of observers spread across the predicted path could easily result in a detailed study of the size and shape of (5) Astraea.

THE EVENT AT ONE GLIMPSE:

• Date and approx. UT time of event: May 22, 2000 @ 17:53 UT
• Magnitude of target star: 9.2
• Magnitude drop [mag]: 1.4
• Estimated maximum duration [s]: 12.3
• Path description: See above.
• Goffin's original chart reference: A00_0502

• Approximate width [km]: 140
• Uncertainty [path widths]: 0.55
• Uncertainty in time [s]: 10
• Map: See below
• 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. Note that the times given on the map below have a negative (-) symbol in front of them. This is to indicate that the predicted times are before 18:00 UT.