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Updated: 2008 APR 13, 21:21 UT
Event Rank : 93
(The event Rank is a measure of the likelihood of observing an event, and is equal to the probability of at least one successful observation by a team of two observers spaced 1/8 path width just inside opposite sides of the predicted path. An event rank of 100 indicates that the prediction is expected to be very accurate).
THE UPDATED PATH
Note: The duration given in the line below is the interval during which the occultation shadow sweeps across the Earth - please see the minute markers on the map to determine the approximate time for your location.
On 2008 May 25 UT, the 135 km diameter asteroid (690) Wratislavia will occult a 10.9 mag star in the constellation Libra for observers along a path passing near the south-west coast of Western Australia, possibly passing over the area from Albany to Bunbury.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.2 mag to 13.0 mag (the magnitude of the asteroid) for at most 9.2 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC.
Additional details of this and other events are available at Steve Preston's website at http://www.asteroidoccultation.com/
EVENT DETAILS SUMMARY :Important Note regarding Accuracy:
The uncertainty interval in path widths given above (and shown as a 1-sigma uncertainty ellipse on the plot) refers to RMS deviation and is applied as a +/- range. In other words, a path uncertainty of 1.0 path widths means that the actual center of the asteroid's shadow path should fall within plus or minus 1 path width of the plotted path center. However path errors larger than 1 sigma have been observed so observers should be alert for primary occultations within plus or minus 3 sigma of the updated path.
Further, almost all asteroidal satellites discovered so far have been found within 10 diameters of the asteroid (since this distance is deep enough within the gravitational well to be stable over long timescales). Therefore, if monitoring for secondary events, observing out to about 10 path-widths either side of the predicted track remains worthwhile.
We therefore recommend that you monitor for events if your observing location is up to +/- 10 path-widths from the predicted track. If not monitoring for occultations by secondary bodies you should observe from locations within 3 sigma of the nominal path.
In terms of time, the predictions are now usually accurate to about +/- 0.3 minute so you should be most attentive during the predicted minute of the event. However if intending to catch a potential satellite occultation you should start observing at least 10 times the predicted central duration before the predicted closest approach time for your location, and continue for a similar period afterwards.
Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2
E. Longitude Latitude U.T. Alt Az Alt
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
119 2 39 -38 33 44 10 18 59 27 99 -16 117 30 47 -38 40 31 120 30 40 -38 25 23 116 0 31 -38 45 15 121 50 12 -38 16 15
117 51 51 -37 35 15 10 19 6 26 100 -15 116 18 27 -37 40 45 119 21 9 -37 28 2 114 46 28 -37 44 8 120 41 43 -37 19 53
116 38 6 -36 35 23 10 19 13 25 101 -14 115 2 46 -36 39 26 118 9 0 -36 29 27 113 28 35 -36 41 17 119 30 50 -36 22 22
115 20 52 -35 33 54 10 19 20 24 102 -13 113 43 6 -35 36 18 116 53 47 -35 29 25 112 6 6 -35 36 21 118 17 13 -35 23 33
113 59 29 -34 30 30 10 19 27 23 103 -11 112 18 37 -34 30 58 115 34 56 -34 27 41 110 38 0 -34 28 52 117 0 21 -34 23 12
112 33 4 -33 24 47 10 19 35 21 104 -10 110 48 12 -33 22 56 114 11 44 -33 23 56 109 2 49 -33 18 10 115 39 39 -33 21 2
111 0 24 -32 16 13 10 19 42 20 105 -8 109 10 13 -32 11 27 112 43 14 -32 17 44 107 18 20 -32 3 17 114 14 20 -32 16 44
109 19 43 -31 4 0 10 19 49 18 107 -7 107 22 15 -30 55 29 111 8 6 -31 8 30 105 21 4 -30 42 39 112 43 20 -31 9 48
107 28 18 -29 46 56 10 19 56 16 108 -5 105 20 16 -29 33 11 109 24 22 -29 55 21 103 4 34 -29 13 25 111 5 9 -29 59 33
105 21 36 -28 22 59 10 20 3 14 109 -2 102 56 38 -28 1 14 107 29 0 -28 36 55 100 14 23 -27 29 13 109 17 33 -28 45 2
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
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[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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