RASNZ Occultation Section - Clarissa Occultation Update

ASTROMETRIC UPDATE:
OCCULTATION BY (302) CLARISSA - 2001 MAY 30

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 crosses the northern New South Wales coast in the Forster area, South Australia around Port Pirie and skimming the southern Western Australian coastline from Esperence to Margaret River. The path given by Occult lies around 2 path widths to the south passing over Newcastle in New South Wales, the northern outskirts of Adelaide and just missing the Western Australian south coast.

UPDATE: 25 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 UCAC1 position of the target star has been used.

Summary:

This updated path lies around three path widths to the north of that given by Goffin and around 1 minute later. The new path crosses the far northern New South Wales coast around Ballina at 16:34:45 UT - Brisbane lies well within the error tolerance of this calculation. Running west the path crosses northern New South Wales and central South Australia to clip the head of the Great Australian Bight (16:37:30 UT). In Western Australia, the path passes just to the south of Kalgoorlie and crosses the northern outskirts of Perth at 16:39:15 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 30, 2001 @ 16:35 UT
Magnitude of target star: 10.5
Magnitude drop [mag]: 3.9
Estimated maximum duration [s]: 3.3
Path description: See above.
Goffin's original chart reference: A01_0516

The Occultation Path:

Approximate width [km]: 38
Uncertainty [path widths]: 3.0 (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 6804-00174-1
Constellation: Scoprius
J2000 position [h,m,s; ^o,',"]: 16h 38m 28.682s; -27^o 03' 29.87"
Position source: UCAC1
Estimated accuracy ["]: 0.054" (0.041", 0.035")
V mag [mag]: 10.48
B-V [mag]: +1.3
Remarks:
The target star is in central Scorpius and lies only 2.1 degrees east southeast of Antares (alpha Sco - magnitude = 1.1). There is a faint 13th magnitude companion 14 " to the south of the target star (GSC 6804 1400).

Data for the minor planet:

Number, name: (302) Clarissa
Approx. diameter [km]: 38
Source of used astrometry: US Naval Observatory - Flagstaff Station (Ron Stone)
Number of used observations: 40
Number of rejected observations: 6
Time covered by the observations: 1998 07 05 - 2001 05 12
Uncertainy Ellipse ["] (major axis, minor axis, PA): 0.044", 0.026", 97°.

Data for the event:

UT date and time of least geocentric approach: 2001 May 30, 16:39.8 UT
Approx. V mag of minor planet at event [mag]: 14.36
Geocentric parallax of minor planet ["]: 5.30
Magnitude drop [mag]: 3.9
Estimated maximum duration [s]: 3.3
Apparent motion of minor planet ["/h]: 36.36
Angular distance to moon, phase of moon [deg,%]: 83, 59%
Update computed by: Steve Preston, Medina, Washington, USA. (OrbFit)

Clarissa 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 25 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]