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Updated: 2008 NOV 13, 23:55 UT
Event Rank : 91
(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 Nov 30 UT, the 97 km diameter asteroid (940) Kordula will occult a 11.5 mag star in the constellation Gemini for observers along a fairly broad path across Western Australia, from Eucla to Exmouth.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.6 mag to 15.1 mag (the magnitude of the asteroid) for at most 11.5 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 Limits Error Limits
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
135 28 1 -38 0 0 18 9 5 26 356 -14 136 37 26 134 17 34 137 47 17 133 4 36
134 21 56 -37 0 0 18 9 17 27 357 -15 135 31 25 133 11 25 136 41 17 131 58 18
133 14 26 -36 0 0 18 9 30 28 358 -16 134 24 3 132 3 43 135 34 0 130 50 23
132 5 22 -35 0 0 18 9 43 29 360 -18 133 15 13 130 54 23 134 25 21 129 40 42
130 54 39 -34 0 0 18 9 57 30 1 -19 132 4 49 129 43 17 133 15 14 128 29 9
129 42 8 -33 0 0 18 10 12 31 2 -20 130 52 44 128 30 16 132 3 32 127 15 33
128 27 40 -32 0 0 18 10 27 32 3 -22 129 38 48 127 15 11 130 50 6 125 59 45
127 11 5 -31 0 0 18 10 43 33 5 -23 128 22 54 125 57 51 129 34 48 124 41 34
125 52 13 -30 0 0 18 10 59 34 6 -25 127 4 50 124 38 5 128 17 28 123 20 45
124 30 50 -29 0 0 18 11 17 35 7 -26 125 44 25 123 15 38 126 57 56 121 57 5
123 6 43 -28 0 0 18 11 35 36 9 -28 124 21 26 121 50 14 125 35 59 120 30 15
121 39 33 -27 0 0 18 11 54 36 11 -29 122 55 37 120 21 35 124 11 23 118 59 54
120 9 2 -26 0 0 18 12 14 37 12 -31 121 26 39 118 49 19 122 43 52 117 25 37
118 34 45 -25 0 0 18 12 35 38 14 -33 119 54 13 117 12 58 121 13 6 115 46 54
116 56 14 -24 0 0 18 12 57 38 16 -34 118 17 52 115 32 1 119 38 43 114 3 7
115 12 54 -23 0 0 18 13 21 39 18 -36 116 37 6 113 45 46 118 0 17 112 13 28
113 24 1 -22 0 0 18 13 45 39 20 -38 114 51 17 111 53 23 116 17 14 110 16 57
111 28 40 -21 0 0 18 14 11 40 22 -39 112 59 39 109 53 45 114 28 54 108 12 12
Uncertainty in time = +/- 8 secs
[Prediction of 2008 Nov 13.0]
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
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