ASTROMETRIC UPDATE:
OCCULTATION BY (250) BETTINA - 2001 MAY 16
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 just east of Darwin to just north of Perth. Occult's path just clips the north-west coast of Western Australia running from just east of Port Hedland to Carnarvon.
UPDATE: 12 May 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. The Tycho-2 position of the target star has been used.
Summary:
This updated path clips the north-west tip of Western Australia running from east of Port Hedland (20:25 UT) to an area just to the north of Carnarvon (20:26 UT). The closest approach to Perth will occur at 20:27 UT.
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: May 16, 2001 @ 20:26 UT
- Magnitude of target star: 11.1
- Magnitude drop [mag]: 2.2
- Estimated maximum duration [s]: 8.0
- Path description: See above.
- Goffin's original chart reference: A01_0510
The Occultation Path:
- Approximate width [km]: 79
- Uncertainty [path widths]: 2.9 (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 7899-06866-1
- Constellation: Corona Australis
- J2000 position [h,m,s; o,',"]: 18h 07m 57.225s; -37o 52' 24.18"
- Position source: Tycho-2
- Estimated accuracy ["]: 0.107" (0.075", 0.076")
- V mag [mag]: 11.10
- Remarks:
- The target star is in northwestern Corona Australis near the border with Sagittarius. It is 2.2 degrees southwest of eta Sagittarii (magnitude = 3.1).
Data for the minor planet:
- Number, name: (250) Bettina
- Approx. diameter [km]: 85.5
- Source of used astrometry: US Naval Observatory - Flagstaff Station (Ron Stone)
- Number of used observations: 65
- Number of rejected observations: 2
- Time covered by the observations: 1998 10 29 - 2001 05 07
- Uncertainy Ellipse ["] (major axis, minor axis, PA): 0.044", 0.015", 94°.
Data for the event:
- UT date and time of least geocentric approach: 2001 May 16, 20:30.1 UT
- Approx. V mag of minor planet at event [mag]: 13.11
- Geocentric parallax of minor planet ["]: 3.29
- Magnitude drop [mag]: 2.2
- Estimated maximum duration [s]: 8.0
- Apparent motion of minor planet ["/h]: 19.87
- Angular distance to moon, phase of moon [deg,%]: 70, 37%
- 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.
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 12 May 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]
