RASNZ Occultation Section - Alauda Occultation Update

ASTROMETRIC UPDATE:
OCCULTATION BY (702) ALAUDA - 2000 APRIL 26

THIS UPDATE REPLACES THE PREVIOUS UPDATE OF 20 APRIL.

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]

[Detailed finder chart by Jan Manek]

Goffin's predicted path crosses central Chile at low altitude, crosses the southern Pacific Ocean and covers the north-eastern extremeties of the North Island of New Zealand. The path then covers the western portions of Papua New Guinea and the extreme north-eastern areas of Irian Jaya. The path predicted by OCCULT lies around half a path width to the north at essentially the same time.

UPDATE: 23 April 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 suggests a path shift of around 3 pathwidths to the east and around 0.8 minute later than that given by Goffin. The new path completely misses New Zealand and the main island of New Guinea. The path passes near New Caledonia (10:32 UT) and crosses the east end of the island of New Britain around 10:34:20 UT.

The asteroid is currently at -40 degrees declination. This results in rather a large scatter in positions and gives a poorer accuracy of prediction. Consequently, observers are still urged to monitor this event.

THE EVENT AT ONE GLIMPSE:

Date and approx. UT time of event: April 26, 2000 @ 10:30 UT
Magnitude of target star: 10.3
Magnitude drop [mag]: 2.0
Estimated maximum duration [s]: 15.6
Path description: See above.
Goffins original chart reference: A00 0428

The Occultation Path:

Approximate width [km]: 205 km
Uncertainty [path widths]: 2.0
Uncertainty in time [s]: 30
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 7774 1412 - 1 = PPM 291150

Constellation: Centaurus

J2000 position [h,m,s; ^o,',"]: 13h 14m 36.287s; -39^o 14' 49.01"

Position source: Tycho 2

Estimated accuracy ["]: 0.05" (0.03", 0.04")

Johson V mag [mag]: 10.29

B-V [mag]: +0.30

Remarks:

The target star is in northern Centaurus, about 2.8 degrees SW from 2.8 mag star iota Centauri. Target star has a close 11.8 mag companion (GSC 7774 1364) only approximately 45" east. To see a detailed finder chart, click here.

Data for the minor planet:

Number, name: (702) Alauda
Approx. diameter [km]: 202
Source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
Number of used observations: 50 USNO, 12 TMO
Number of rejected observations: 2 USNO, 1 TMO
Time covered by the observations: 1998 11 15 - 2000 04 19
RMS residuals ["] (RA,DE): 0.12", 0.17"
Estimated positional accuracy at epoch of event ["]: 0.20"

Data for the event:

UT date and time of least geocentric approach: 2000 April 26, 10:28.4 UTC
Approx. V mag of minor planet at event [mag]: 12.1
Geocentric parallax of minor planet ["]: 3.903
Magnitude drop [mag]: 2.0
Estimated maximum duration [s]: 15.6
Apparent motion of minor planet ["/h]: 28.58
Angular distance to moon, phase of moon [deg,%]: 88, 54%
Update computed by: Jan Manek

Alauda 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 23 April 2000.
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]