ASTROMETRIC UPDATE:
OCCULTATION BY (308) POLYXO - 2001 NOVEMBER 21
[Prediction using OCCULT software + finder charts]
The prediction given by OCCULT runs centrally across the North Island of New Zealand.
UPDATE: 15 November 2001
THE UPDATED PATH
This updated path lies around two path widths to the north of that given by Occult and around 10 seconds later. The path crosses the North Island centred on Auckland at 8:23 UT. The nominal path covers the area between Whangarei and Hamilton although the error band covers most of the North Island north of Wanganui and Napier.
The event will occur at quite low altitude with Auckland sighting the star at 15 degrees at the time of the apulse.
Calculation Source
This prediction update has been computed by Steve Preston of Medina, Washington (state) in the United States based on astrometry from Ron Stone of the US Naval Observatory - Flagstaff Station, USA and Bill Owen of Table Mountain Observatory - JPL supplemented with data from the AstDys database. The UCAC position of the target star has been used.
Additional details of this and other events are available at Steve Preston's website at http://www.oz.net/~stevepr/Asteroids/asteroid.htm
EVENT DETAILS SUMMARY:
- Date and approx. UT time of event: 2001 Novembe 21, 8:23 UT
- Magnitude of target star: 10.9
- Magnitude drop [mag]: 2.8
- Estimated maximum duration [s]: 3.3
- Angular distance to moon, phase of moon [deg,%]: 37, 35%
The Occultation Path:
- Approximate width [km]: 169
- Uncertainty [path widths]: +/- 0.59 (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 !!!!
Data for the target star:
- Name: TYC 6273-01425-1
- Constellation: Sagittarius
- J2000 position [h,m,s; o,',"]: 18h 20m 58.7261s; -20o 03' 50.491"
- Position source: UCAC
- Estimated accuracy ["]: 0.042" (0.030", 0.032")
- V mag [mag]: 10.9
- B-V [mag]: +0.47
- Remarks:
- The target star is in central northern Sagittarius. It lies only 1.1 degrees northwest of 21 Sagittarii (magnitude = 4.9). Finder charts are available along with the prediction by clicking here.
Data for the minor planet:
- Number, name: (308) Polyxo
- Approx. diameter [km]: 140
- Source of used astrometry: US Naval Observatory - Flagstaff Station (Ron Stone), TMO-JPL (Bill Owen), AstDys
- Number of used observations: 745
- Number of rejected observations: 64
- Time covered by the observations: 1902 10 07 - 2001 08 17
- 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]
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[Observing Details]
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[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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