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Updated: 2009 OCT 29, 21:53 UT
Event Rank : 12
(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 2009 Dec 18 UT, the 18 km diameter asteroid (3896) Pordenone will occult a 10.2 mag star in the constellation Sextans for observers along a narrow path of significant uncertainty running along the coast of Western Australia from Kalbarri to Perth and then to Walpole.
In the case of an occultation, the combined light of the asteroid and the star will drop by 6.4 mag to 16.6 mag (the magnitude of the asteroid) for at most 1.9 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, 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
110 10 38 -21 57 4 17 26 27 30 80 -43 110 20 17 -21 54 14 110 0 55 -21 59 53 112 1 1 -21 23 44 108 12 49 -22 30 7
110 41 46 -22 38 32 17 26 36 31 80 -42 110 51 23 -22 35 41 110 32 6 -22 41 22 112 31 40 -22 4 59 108 44 37 -23 11 49
111 11 51 -23 20 7 17 26 46 31 79 -42 111 21 26 -23 17 15 111 2 14 -23 22 58 113 1 21 -22 46 21 109 15 14 -23 53 38
111 40 56 -24 1 50 17 26 55 31 78 -41 111 50 28 -23 58 57 111 31 20 -24 4 43 113 30 8 -23 27 51 109 44 43 -24 35 35
112 9 2 -24 43 42 17 27 4 32 78 -40 112 18 33 -24 40 48 111 59 28 -24 46 35 113 58 2 -24 9 30 110 13 7 -25 17 41
112 36 12 -25 25 42 17 27 14 32 77 -39 112 45 43 -25 22 47 112 26 39 -25 28 38 114 25 5 -24 51 17 110 40 29 -25 59 56
113 2 29 -26 7 53 17 27 23 32 76 -38 113 11 59 -26 4 57 112 52 56 -26 10 49 114 51 19 -25 33 14 111 6 50 -26 42 21
113 27 52 -26 50 14 17 27 32 32 76 -38 113 37 23 -26 47 17 113 18 19 -26 53 12 115 16 46 -26 15 21 111 32 14 -27 24 57
113 52 25 -27 32 47 17 27 41 33 75 -37 114 1 56 -27 29 48 113 42 51 -27 35 45 115 41 26 -26 57 39 111 56 40 -28 7 45
114 16 8 -28 15 31 17 27 51 33 74 -36 114 25 40 -28 12 31 114 6 33 -28 18 31 116 5 22 -27 40 8 112 20 11 -28 50 44
114 39 2 -28 58 28 17 28 0 33 73 -35 114 48 36 -28 55 26 114 29 26 -29 1 29 116 28 33 -28 22 49 112 42 48 -29 33 57
115 1 8 -29 41 37 17 28 9 33 73 -34 115 10 43 -29 38 35 114 51 30 -29 44 40 116 51 1 -29 5 44 113 4 31 -30 17 23
115 22 27 -30 25 1 17 28 18 33 72 -34 115 32 4 -30 21 57 115 12 46 -30 28 6 117 12 46 -29 48 52 113 25 21 -31 1 4
115 42 58 -31 8 40 17 28 28 33 71 -33 115 52 39 -31 5 34 115 33 15 -31 11 46 117 33 49 -30 32 14 113 45 19 -31 45 0
116 2 43 -31 52 34 17 28 37 33 71 -32 116 12 27 -31 49 27 115 52 57 -31 55 41 117 54 10 -31 15 51 114 4 24 -32 29 11
116 21 42 -32 36 45 17 28 46 33 70 -31 116 31 29 -32 33 36 116 11 51 -32 39 54 118 13 50 -31 59 44 114 22 37 -33 13 40
116 39 54 -33 21 13 17 28 56 33 69 -30 116 49 45 -33 18 3 116 29 59 -33 24 23 118 32 47 -32 43 53 114 39 58 -33 58 27
116 57 19 -34 5 59 17 29 5 33 68 -30 117 7 15 -34 2 47 116 47 19 -34 9 11 118 51 4 -33 28 20 114 56 25 -34 43 32
117 13 56 -34 51 4 17 29 14 33 68 -29 117 23 58 -34 47 50 117 3 52 -34 54 17 119 8 38 -34 13 6 115 11 59 -35 28 57
117 29 46 -35 36 29 17 29 23 33 67 -28 117 39 53 -35 33 13 117 19 36 -35 39 44 119 25 31 -34 58 11 115 26 38 -36 14 43
117 44 47 -36 22 15 17 29 33 33 66 -27 117 55 0 -36 18 57 117 34 31 -36 25 32 119 41 40 -35 43 36 115 40 22 -37 0 50
117 58 58 -37 8 23 17 29 42 33 66 -26 118 9 18 -37 5 4 117 48 35 -37 11 42 119 57 6 -36 29 22 115 53 8 -37 47 20
Uncertainty in time = +/- 12 secs
Prediction of 2009 Dec 16.0
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