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Updated: 2012 JAN 26, 12:11 UT
Event Rank : 99
(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 2012 Feb 07 UT, the 256 km diameter asteroid (15) Eunomia will occult a 11.8 mag star in the constellation Taurus for observers along a path in south-east Western Australia near Kalgoorlie.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.1 mag to 9.4 mag (the magnitude of the asteroid) for at most 19.8 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 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
154 25 24 -52 0 0 11 40 48 1 320 -17 150 49 8 ... .. .. 148 29 4 ... .. ..
153 0 44 -51 0 0 11 40 47 3 321 -17 149 28 7 156 30 49 147 10 16 ... .. ..
151 37 0 -50 0 0 11 40 47 4 322 -17 148 7 42 155 3 31 145 51 50 ... .. ..
150 14 2 -49 0 0 11 40 45 5 323 -17 146 47 44 153 37 19 144 33 40 155 46 15
148 51 41 -48 0 0 11 40 44 7 324 -18 145 28 4 152 12 3 143 15 37 154 18 59
147 29 49 -47 0 0 11 40 41 8 325 -18 144 8 36 150 47 33 141 57 33 152 52 40
146 8 17 -46 0 0 11 40 39 9 326 -18 142 49 11 149 23 40 140 39 22 151 27 10
144 46 56 -45 0 0 11 40 36 11 327 -18 141 29 41 148 0 15 139 20 55 150 2 18
143 25 39 -44 0 0 11 40 32 12 328 -18 140 9 59 146 37 9 138 2 6 148 37 55
142 4 19 -43 0 0 11 40 29 13 329 -18 138 49 57 145 14 15 136 42 46 147 13 54
140 42 47 -42 0 0 11 40 24 15 330 -18 137 29 28 143 51 24 135 22 48 145 50 5
139 20 56 -41 0 0 11 40 20 16 331 -18 136 8 24 142 28 29 134 2 4 144 26 21
137 58 37 -40 0 0 11 40 14 18 332 -17 134 46 36 141 5 21 132 40 25 143 2 34
136 35 42 -39 0 0 11 40 9 19 333 -17 133 23 56 139 41 53 131 17 43 141 38 36
135 12 3 -38 0 0 11 40 2 20 334 -17 132 0 15 138 17 57 129 53 47 140 14 18
133 47 32 -37 0 0 11 39 56 22 336 -17 130 35 23 136 53 23 128 28 27 138 49 33
132 21 58 -36 0 0 11 39 48 23 337 -16 129 9 9 135 28 4 127 1 31 137 24 12
130 55 11 -35 0 0 11 39 40 24 338 -16 127 41 22 134 1 49 125 32 47 135 58 6
129 27 0 -34 0 0 11 39 32 26 339 -15 126 11 48 132 34 29 124 2 1 134 31 6
127 57 14 -33 0 0 11 39 23 27 340 -15 124 40 15 131 5 54 122 28 55 133 3 2
126 25 38 -32 0 0 11 39 13 29 342 -14 123 6 25 129 35 52 120 53 11 131 33 42
124 51 57 -31 0 0 11 39 3 30 343 -13 121 29 59 128 4 10 119 14 27 130 2 57
123 15 55 -30 0 0 11 38 52 31 345 -12 119 50 37 126 30 33 117 32 18 128 30 32
121 37 12 -29 0 0 11 38 40 33 346 -11 118 7 51 124 54 47 115 46 11 126 56 13
119 55 24 -28 0 0 11 38 27 34 348 -10 116 21 13 123 16 32 113 55 29 125 19 45
118 10 4 -27 0 0 11 38 14 35 350 -9 114 30 3 121 35 28 111 59 24 123 40 49
116 20 39 -26 0 0 11 38 0 36 352 -8 112 33 36 119 51 10 109 56 55 121 59 3
114 26 30 -25 0 0 11 37 44 38 354 -7 110 30 52 118 3 8 107 46 40 120 14 5
112 26 45 -24 0 0 11 37 28 39 356 -5 108 20 31 116 10 47 105 26 50 118 25 23
110 20 19 -23 0 0 11 37 10 40 358 -4 106 0 48 114 13 24 102 54 42 116 32 22
Latitude Latitude Latitude Latitude
109 0 0 -22 23 42 11 36 59 41 360 -3 -24 17 46 -20 33 53 -25 33 18 -19 25 34
108 0 0 -21 57 31 11 36 50 41 1 -2 -23 50 54 -20 8 18 -25 5 57 -19 0 21
107 0 0 -21 32 8 11 36 41 41 2 -1 -23 24 52 -19 43 31 -24 39 28 -18 35 54
106 0 0 -21 7 34 11 36 33 42 4 0 -22 59 40 -19 19 31 -24 13 49 -18 12 14
Uncertainty in time = +/- 6 secs
Prediction of 2012 Jan 26.0
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