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Updated: 2010 JUL 20, 21:22 UT
Event Rank : 29
(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 2010 Aug 26 UT, the 125 km diameter asteroid (159) Aemilia will occult a 11.4 mag star in the constellation Sagittarius for observers along a widely uncertain north-to-south path across Australia centred from just west of Darwin to Esperance in Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.5 mag to 13.8 mag (the magnitude of the asteroid) for at most 42.8 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
128 57 2 -11 40 52 15 10 20 38 253 -86 129 50 42 -11 39 56 128 4 21 -11 41 20 134 10 17 -11 29 3 124 15 16 -11 38 14
128 22 47 -12 46 8 15 10 58 38 254 -85 129 16 11 -12 45 26 127 30 21 -12 46 24 133 33 59 -12 35 45 123 42 0 -12 42 30
127 50 4 -13 50 54 15 11 37 39 255 -84 128 43 16 -13 50 23 126 57 48 -13 50 58 132 59 39 -13 41 48 123 9 59 -13 46 20
127 18 48 -14 55 10 15 12 16 39 256 -83 128 11 52 -14 54 51 126 26 40 -14 55 4 132 27 10 -14 47 15 122 39 9 -14 49 46
126 48 56 -15 59 1 15 12 55 40 257 -82 127 41 54 -15 58 51 125 56 51 -15 58 46 131 56 27 -15 52 9 122 9 27 -15 52 50
126 20 24 -17 2 29 15 13 34 41 258 -81 127 13 19 -17 2 28 125 28 20 -17 2 5 131 27 24 -16 56 34 121 40 51 -16 55 35
125 53 9 -18 5 36 15 14 12 41 258 -80 126 46 5 -18 5 43 125 1 4 -18 5 4 130 59 58 -18 0 32 121 13 18 -17 58 2
125 27 9 -19 8 24 15 14 51 41 259 -79 126 20 9 -19 8 39 124 34 59 -19 7 45 130 34 5 -19 4 6 120 46 47 -19 0 14
125 2 22 -20 10 55 15 15 30 42 260 -78 125 55 28 -20 11 17 124 10 6 -20 10 10 130 9 43 -20 7 19 120 21 16 -20 2 12
124 38 47 -21 13 12 15 16 9 42 261 -77 125 32 2 -21 13 39 123 46 21 -21 12 21 129 46 49 -21 10 13 119 56 44 -21 3 58
124 16 22 -22 15 15 15 16 47 43 262 -76 125 9 49 -22 15 48 123 23 45 -22 14 19 129 25 23 -22 12 49 119 33 10 -22 5 33
123 55 7 -23 17 8 15 17 26 43 263 -75 124 48 48 -23 17 46 123 2 15 -23 16 7 129 5 22 -23 15 10 119 10 33 -23 7 0
123 35 2 -24 18 50 15 18 5 43 264 -74 124 29 0 -24 19 32 122 41 53 -24 17 45 128 46 46 -24 17 18 118 48 52 -24 8 19
123 16 5 -25 20 25 15 18 44 43 265 -73 124 10 23 -25 21 11 122 22 37 -25 19 15 128 29 36 -25 19 14 118 28 9 -25 9 33
122 58 18 -26 21 52 15 19 23 44 266 -72 123 52 58 -26 22 41 122 4 28 -26 20 40 128 13 51 -26 20 59 118 8 21 -26 10 42
122 41 41 -27 23 15 15 20 1 44 267 -71 123 36 45 -27 24 7 121 47 27 -27 21 59 127 59 33 -27 22 36 117 49 31 -27 11 48
122 26 15 -28 24 33 15 20 40 44 268 -70 123 21 46 -28 25 27 121 31 33 -28 23 16 127 46 41 -28 24 5 117 31 38 -28 12 52
122 12 0 -29 25 49 15 21 19 44 269 -70 123 8 2 -29 26 45 121 16 49 -29 24 30 127 35 18 -29 25 29 117 14 42 -29 13 56
121 58 59 -30 27 4 15 21 58 44 270 -69 122 55 33 -30 28 1 121 3 15 -30 25 43 127 25 27 -30 26 47 116 58 46 -30 15 1
121 47 13 -31 28 19 15 22 36 44 271 -68 122 44 24 -31 29 16 120 50 54 -31 26 57 127 17 8 -31 28 2 116 43 50 -31 16 8
121 36 45 -32 29 34 15 23 15 44 272 -67 122 34 34 -32 30 32 120 39 47 -32 28 12 127 10 26 -32 29 14 116 29 56 -32 17 18
121 27 37 -33 30 53 15 23 54 44 273 -66 122 26 9 -33 31 50 120 29 57 -33 29 31 127 5 24 -33 30 25 116 17 6 -33 18 33
121 19 52 -34 32 14 15 24 33 44 274 -65 122 19 10 -34 33 11 120 21 28 -34 30 53 127 2 7 -34 31 35 116 5 22 -34 19 55
121 13 34 -35 33 41 15 25 12 44 275 -64 122 13 41 -35 34 35 120 14 21 -35 32 21 127 0 38 -35 32 46 115 54 47 -35 21 23
121 8 48 -36 35 13 15 25 50 44 276 -63 122 9 48 -36 36 5 120 8 43 -36 33 55 127 1 3 -36 33 58 115 45 23 -36 23 0
Uncertainty in time = +/- 97 secs
Prediction of 2010 Jul 21.0
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