RASNZ Occultation Section - Impala Occultation Update

ASTROMETRIC UPDATE:
OCCULTATION BY (1320) IMPALA - 2001 JUNE 18

CHECK THIS PAGE REGULARLY FOR FURTHER UPDATES AND CHANGES TO THE TRACK.

YOU MUST RELOAD THIS PAGE USING YOUR BROWSER'S
RELOAD/REFRESH BUTTON TO OBTAIN UPDATES!

[Prediction by Edwin Goffin]

[Prediction using OCCULT software]

The path given by Edwin Goffin runs from around Rockhampton on the central Queensland coast southwest across southern Queensland and western New South Wales and Victoria to enter the southern ocean around the Victoria/South Australian border. The path given by Occult runs north to south through the Tasman sea without any landfall. It lies around 0.7" to the east with little difference in expected time.

UPDATE: 15 June 2001

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

Summary:

This updated path lies around 1 path width to the northwest and around 90 seconds earlier than that given by Goffin. The path crosses the central Queensland coast just east of Gladstone (15:36 UT) running southwest. Running just east of Roma in southern Queensland and Bourke in western New South Wales, the path passes close to Mildura on the New South Wales/Victoria border (15:38:15 UT). In southeastern South Australia, the path passes through the Millicent district (15:39 UT) before leaving the Australian landmass.

Additional details of this and other events are available at Steve Preston's website at http://www.oz.net/~stevepr/Asteroids/asteroid.htm

THE EVENT AT ONE GLIMPSE:

Date and approx. UT time of event: June 18, 2001 @ 15:37 UT
Magnitude of target star: 10.88
Magnitude drop [mag]: 3.1
Estimated maximum duration [s]: 4.9
Path description: See above.
Goffin's original chart reference: A01_0645

The Occultation Path:

Approximate width [km]: 72
Uncertainty [path widths]: 1.4 (1 sigma error band)
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 5606-01036-1 = PPM 717724
Constellation: Libra
J2000 position [h,m,s; ^o,',"]: 15h 20m 50.969s; -14^o 51' 42.56"
Position source: UCAC 1
Estimated accuracy ["]: 0.058" (0.030", 0.050")
V mag [mag]: 10.88
B-V [mag]: +1.35
Remarks:
The target star is in central Libra. It lies only 41' north of omicron Librae (magnitude = 6.1) and only 8' south-southeast of the star HIP 75085 = SAO 159185 (magnitude 7.4).

Data for the minor planet:

Number, name: (1320) Impala
Approx. diameter [km]: 45.6
Source of used astrometry: US Naval Observatory - Flagstaff Station (Ron Stone), AstDys
Number of used observations: 152
Number of rejected observations: 25
Time covered by the observations: 1934 05 13 - 2001 06 07
Uncertainy Ellipse ["] (major axis, minor axis, PA): 0.028", 0.023", -166°.

Data for the event:

UT date and time of least geocentric approach: 2001 June 18, 15:40.6 UT
Approx. V mag of minor planet at event [mag]: 13.88
Geocentric parallax of minor planet ["]: 6.07
Magnitude drop [mag]: 3.1
Estimated maximum duration [s]: 4.9
Apparent motion of minor planet ["/h]: 31.86
Angular distance to moon, phase of moon [deg,%]: 179, 10%
Update computed by: Steve Preston, Medina, Washington, USA. (OrbFit)

Impala 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]

This page may have been updated since 15 June 2001.
Hit your browser's RELOAD button to get the latest version.
[Site Map] [What's an Occultation?]
[Total Occultations] [Grazing Occultations] [Planetary Occultations] [Jovian Satellite Eclipses]
[Timing Occultations] [Reporting Observations] [Coming Events] [Software]
[About Us] [Publications] [Membership] [Links]

[Top of Page][Return to Home Page]