RASNZ Occultation Section - Asterope Occultation Update

ASTROMETRIC UPDATE:
OCCULTATION BY (233) ASTEROPE - 2000 MAY 5

THIS UPDATE REPLACES THE PREVIOUS UPDATE OF 29 APRIL.

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[Prediction by Edwin Goffin]

[Prediction using OCCULT software]

[Detailed finder chart by Jan Manek]

Goffin's predicted path crosses from the south-east including Flinders Island in Bass Strait, crossing Wilson's Promontory and metropolitan Melbourne and Ballarat. The path runs to the north-west including Port Augusta in South Australia and leaves the Western Australian coastline just south of Broome. The OCCULT path is perhaps half a path width to the south-west and around 30 seconds later.

UPDATE: 3 May 2000

This prediction update is supplied by Jan Manek of the Stefanik Observatory, Prague, and is based on USNO/Flagstaff and TMO astrometry for the minor planet and the TYC-2 star position.

Summary:

This update places the path around 3 path widths and 20 seconds later than that given by Goffin. The path now clips the extreme south-west corner of Tasmania (11:55:30 UT) and passes just beyond the south-western tips of Kangaroo Island and the Eyre Peninsula (11:57:30). The path crosses the coastline at the South Australia/Western Australian border (11:58:35 UT) and runs to the north-west crossing the coast between Onslow and Karratha (12:01:00 UT).

With the path uncertainties outlined below, observers in and around Adelaide/Kangaroo Island/ York and Eyre Peninsulas in South Australia and Exmouth in Western Australia are strongly urged to monitor this event.

THE EVENT AT ONE GLIMPSE:

Date and approx. UT time of event: May 5, 2000 @ 11:58 UT
Magnitude of target star: 10.7
Magnitude drop [mag]: 1.9
Estimated maximum duration [s]: 9.6
Path description: See above.
Goffins original chart reference: A00 0511

The Occultation Path:

Approximate width [km]: 130 km
Uncertainty [path widths]: 1.5
Uncertainty in time [s]: 15
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.

Data for the target star:

Name: TYC 5547 647-1 = PPM 717192

Constellation: Virgo

J2000 position [h,m,s; ^o,',"]: 13h 20m 57.493s; -11^o 04' 02.43"

Position source: Tycho 2

Estimated accuracy ["]: 0.07" (0.05", 0.05")

Johson V mag [mag]: 10.66

B-V [mag]: +1.13

Remarks:

The target star is just over one degree west of Spica (alpha Vir). The 6.7 mag star SAO 157869 lies 17' to the south-west of the target star.
To see a detailed finder chart, click here. Note that this chart is at a slightly different scale to those previously prepared by Jan.

Data for the minor planet:

Number, name: (233) Asterope
Approx. diameter [km]: 108
Source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
Number of used observations: 65 USNO, 7 TMO
Number of rejected observations: 6 USNO, 1 TMO
Time covered by the observations: 1998 11 04 - 2000 04 27
RMS residuals ["] (RA,DE): 0.07", 0.07"
Estimated positional accuracy at epoch of event ["]: 0.07"

Data for the event:

UT date and time of least geocentric approach: 2000 May 5, 11:57.4 UTC
Approx. V mag of minor planet at event [mag]: 12.4
Geocentric parallax of minor planet ["]: 4.673
Magnitude drop [mag]: 1.9
Estimated maximum duration [s]: 9.6
Apparent motion of minor planet ["/h]: 29.53
Angular distance to moon, phase of moon [deg,%]: 140, 2%
Update computed by: Jan Manek

Asterope Update

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.

Use these links for further information:
[Planetary Occultations] [Using the Predictions]
[Observing Details] [Timing Details] [Reporting Details] [Report Form]
[Asteroid Occultation Results]

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