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Updated: 2011 JUL 02, 02:06 UT
Event Rank : 86
(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 Aug 31 UT, the 141 km diameter asteroid (308) Polyxo will occult a 12.9 mag star in the constellation Aquarius for observers along a path passing near Cobar, Broken Hill, Port Pirie and Adelaide.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.3 mag to 11.7 mag (the magnitude of the asteroid) for at most 12.8 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
158 49 9 -27 24 31 19 32 59 6 269 -2 ... .. .. .. .. .. 154 23 7 -27 2 40 ... .. .. .. .. .. 150 54 1 -26 31 35
154 47 29 -28 6 10 19 33 8 9 271 -6 159 42 42 -28 26 39 151 33 45 -27 39 49 ... .. .. .. .. .. 148 37 10 -27 6 35
151 55 1 -28 43 47 19 33 16 12 273 -8 155 22 16 -29 9 42 149 13 6 -28 15 19 163 13 0 -29 26 19 146 36 22 -27 40 41
149 32 52 -29 19 39 19 33 25 14 274 -10 152 24 18 -29 47 56 147 9 54 -28 49 52 156 55 31 -30 16 40 144 46 49 -28 14 11
147 28 49 -29 54 32 19 33 33 15 275 -12 149 59 28 -30 24 16 145 18 44 -29 23 46 153 37 2 -30 56 28 143 5 43 -28 47 16
145 37 8 -30 28 46 19 33 42 17 276 -14 147 53 52 -30 59 33 143 36 28 -29 57 14 151 2 32 -31 33 44 141 31 15 -29 20 2
143 54 34 -31 2 33 19 33 50 18 277 -15 146 1 11 -31 34 10 142 1 7 -30 30 23 148 51 10 -32 9 44 140 2 8 -29 52 34
142 19 2 -31 36 2 19 33 58 20 278 -17 144 17 56 -32 8 19 140 31 21 -31 3 18 146 54 39 -32 44 57 138 37 28 -30 24 57
140 49 10 -32 9 16 19 34 7 21 279 -18 142 41 58 -32 42 9 139 6 10 -31 36 2 145 8 40 -33 19 40 137 16 33 -30 57 11
139 23 58 -32 42 21 19 34 15 22 280 -19 141 11 47 -33 15 46 137 44 52 -32 8 39 143 30 40 -33 54 1 135 58 51 -31 29 20
138 2 40 -33 15 18 19 34 24 23 281 -20 139 46 22 -33 49 12 136 26 51 -32 41 11 141 58 56 -34 28 8 134 43 57 -32 1 26
136 44 41 -33 48 11 19 34 32 24 282 -21 138 24 56 -34 22 32 135 11 42 -33 13 39 140 32 18 -35 2 4 133 31 28 -32 33 29
135 29 36 -34 21 1 19 34 41 25 283 -22 137 6 54 -34 55 48 133 59 2 -33 46 6 139 9 54 -35 35 54 132 21 9 -33 5 31
134 17 2 -34 53 50 19 34 49 25 284 -23 135 51 47 -35 29 1 132 48 35 -34 18 33 137 51 6 -36 9 40 131 12 45 -33 37 34
133 6 40 -35 26 39 19 34 57 26 285 -24 134 39 13 -36 2 14 131 40 4 -34 51 0 136 35 23 -36 43 23 130 6 3 -34 9 38
131 58 16 -35 59 30 19 35 6 27 286 -25 133 28 54 -36 35 28 130 33 17 -35 23 30 135 22 21 -37 17 7 129 0 52 -34 41 44
130 51 36 -36 32 23 19 35 14 27 287 -25 132 20 34 -37 8 44 129 28 4 -35 56 2 134 11 38 -37 50 51 127 57 4 -35 13 53
129 46 30 -37 5 20 19 35 23 28 289 -26 131 13 59 -37 42 4 128 24 14 -36 28 37 133 3 0 -38 24 39 126 54 31 -35 46 6
128 42 49 -37 38 21 19 35 31 29 290 -27 130 8 59 -38 15 27 127 21 40 -37 1 17 131 56 13 -38 58 30 125 53 5 -36 18 23
127 40 23 -38 11 27 19 35 40 29 291 -28 129 5 24 -38 48 56 126 20 14 -37 34 3 130 51 3 -39 32 27 124 52 40 -36 50 45
126 39 5 -38 44 40 19 35 48 30 292 -28 128 3 6 -39 22 31 125 19 50 -38 6 54 129 47 22 -40 6 29 123 53 10 -37 23 14
125 38 50 -39 17 59 19 35 56 30 293 -29 127 1 57 -39 56 12 124 20 22 -38 39 52 128 45 0 -40 40 39 122 54 31 -37 55 48
124 39 30 -39 51 26 19 36 5 31 294 -29 126 1 50 -40 30 2 123 21 44 -39 12 57 127 43 50 -41 14 57 121 56 36 -38 28 30
123 41 1 -40 25 1 19 36 13 31 295 -30 125 2 40 -41 4 0 122 23 52 -39 46 10 126 43 45 -41 49 23 120 59 22 -39 1 19
122 43 18 -40 58 45 19 36 22 32 296 -30 124 4 20 -41 38 7 121 26 41 -40 19 32 125 44 38 -42 23 59 120 2 46 -39 34 16
Uncertainty in time = +/- 8 secs
Prediction of 2011 Jul 2.0
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