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Updated: 2011 AUG 05, 16:39 UT
Event Rank : 9
(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 2011 Dec 06 UT, the 11 km diameter asteroid (5067) Occidental will occult a 6.4 mag star in the constellation Sextans for observers along a very narrow path of significant uncertainty across Australia from near Exmouth across Western Australia and South Australia to Victoria, from Mildura to Echuca and then Sale. The one sigma limit includes most of Victoria except the south-west, including Melbourne, and south-western New South Wales.
In the case of an occultation, the combined light of the asteroid and the star will drop by 11.3 mag to 17.7 mag (the magnitude of the asteroid) for at most 1.0 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: .
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
151 41 25 -42 0 0 16 35 28 35 45 -14 151 32 30 151 50 18 149 14 5 154 3 24
150 37 9 -41 0 0 16 35 14 35 47 -16 150 28 14 150 46 3 148 9 30 152 59 15
149 31 12 -40 0 0 16 35 1 35 48 -17 149 22 15 149 40 8 147 2 57 151 53 38
148 23 25 -39 0 0 16 34 47 35 50 -18 148 14 25 148 32 23 145 54 16 150 46 26
147 13 38 -38 0 0 16 34 32 35 52 -20 147 4 35 147 22 41 144 43 17 149 37 30
146 1 41 -37 0 0 16 34 18 34 53 -21 145 52 32 146 10 48 143 29 46 148 26 41
144 47 20 -36 0 0 16 34 3 34 55 -23 144 38 5 144 56 33 142 13 28 147 13 48
143 30 20 -35 0 0 16 33 48 34 57 -24 143 20 58 143 39 41 140 54 4 145 58 39
142 10 25 -34 0 0 16 33 32 33 59 -26 142 0 53 142 19 55 139 31 12 144 40 58
140 47 14 -33 0 0 16 33 17 33 60 -27 140 37 30 140 56 55 138 4 27 143 20 30
139 20 21 -32 0 0 16 33 1 32 62 -29 139 10 24 139 30 16 136 33 17 141 56 55
137 49 18 -31 0 0 16 32 45 31 64 -30 137 39 4 137 59 30 134 57 1 140 29 49
136 13 27 -30 0 0 16 32 29 31 66 -32 136 2 53 136 23 59 133 14 47 138 58 45
134 32 2 -29 0 0 16 32 12 30 67 -33 134 21 2 134 42 58 131 25 28 137 23 7
132 44 1 -28 0 0 16 31 55 28 69 -35 132 32 31 132 55 28 129 27 33 135 42 14
130 48 5 -27 0 0 16 31 38 27 71 -37 130 35 55 131 0 9 127 18 51 133 55 8
128 42 19 -26 0 0 16 31 20 26 73 -38 128 29 19 128 55 13 124 56 4 132 0 38
Latitude Latitude Latitude Latitude
127 0 0 -25 15 1 16 31 7 24 74 -40 -25 20 51 -25 9 12 -26 51 41 -23 42 30
126 0 0 -24 50 13 16 30 59 23 75 -40 -24 56 0 -24 44 28 -26 26 1 -23 18 28
125 0 0 -24 26 35 16 30 52 23 75 -41 -24 32 19 -24 20 52 -26 1 34 -22 55 32
124 0 0 -24 4 5 16 30 45 22 76 -42 -24 9 46 -23 58 25 -25 38 18 -22 33 44
123 0 0 -23 42 43 16 30 38 21 77 -42 -23 48 22 -23 37 6 -25 16 12 -22 13 1
122 0 0 -23 22 30 16 30 32 20 77 -43 -23 28 6 -23 16 54 -24 55 17 -21 53 23
121 0 0 -23 3 23 16 30 26 19 78 -43 -23 8 57 -22 57 50 -24 35 32 -21 34 51
120 0 0 -22 45 22 16 30 20 18 78 -44 -22 50 54 -22 39 51 -24 16 55 -21 17 23
119 0 0 -22 28 28 16 30 14 18 79 -44 -22 33 58 -22 22 59 -23 59 27 -21 0 59
118 0 0 -22 12 39 16 30 9 17 79 -45 -22 18 7 -22 7 12 -23 43 6 -20 45 38
117 0 0 -21 57 55 16 30 4 16 80 -45 -22 3 22 -21 52 30 -23 27 53 -20 31 21
116 0 0 -21 44 16 16 29 59 15 80 -46 -21 49 41 -21 38 52 -23 13 46 -20 18 6
115 0 0 -21 31 41 16 29 55 14 81 -46 -21 37 4 -21 26 18 -23 0 45 -20 5 53
114 0 0 -21 20 9 16 29 51 13 81 -46 -21 25 31 -21 14 48 -22 48 50 -19 54 43
113 0 0 -21 9 41 16 29 47 12 82 -46 -21 15 2 -21 4 21 -22 38 1 -19 44 34
Uncertainty in time = +/- 10 secs
Prediction of 2011 Nov 27.0
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