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Updated: 2009 JUN 25, 18:57 UT
Event Rank : 39
(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 Aug 07 UT, the 29 km diameter asteroid (1196) Sheba will occult a 11.0 mag star in the constellation Ophiuchus for observers along an somewhat uncertain path beginning near Coral Bay in Western Australia. The path then passes near Paynes Find, Southern Cross, Norseman and Esperance. Later the path is centred over Hobart in Tasmania.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.7 mag to 14.7 mag (the magnitude of the asteroid) for at most 4.3 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
110 40 37 -18 0 0 15 18 31 49 260 -70 110 28 56 110 52 20 109 49 44 111 32 18
111 7 58 -19 0 0 15 18 49 48 261 -70 110 56 6 111 19 53 110 16 18 112 0 29
111 37 4 -20 0 0 15 19 7 48 262 -71 111 25 0 111 49 11 110 44 33 112 30 28
112 8 1 -21 0 0 15 19 25 48 263 -71 111 55 44 112 20 21 111 14 35 113 2 24
Latitude Latitude Latitude Latitude
113 0 0 -22 33 6 15 19 54 47 265 -71 -22 54 38 -22 11 19 -24 5 36 -20 55 37
114 0 0 -24 10 27 15 20 23 46 266 -72 -24 30 36 -23 50 5 -25 37 14 -22 39 34
115 0 0 -25 38 44 15 20 50 45 267 -72 -25 57 45 -25 19 32 -27 0 46 -24 13 15
116 0 0 -26 59 19 15 21 15 44 268 -72 -27 17 23 -26 41 7 -28 17 20 -25 38 22
117 0 0 -28 13 18 15 21 38 43 269 -72 -28 30 32 -27 55 56 -29 27 51 -26 56 11
118 0 0 -29 21 30 15 22 0 42 269 -72 -29 38 1 -29 4 51 -30 33 2 -28 7 42
119 0 0 -30 24 36 15 22 20 41 270 -72 -30 40 29 -30 8 35 -31 33 29 -29 13 41
120 0 0 -31 23 8 15 22 39 40 270 -72 -31 38 29 -31 7 42 -32 29 41 -30 14 47
121 0 0 -32 17 35 15 22 56 39 270 -72 -32 32 26 -32 2 38 -33 22 2 -31 11 29
122 0 0 -33 8 19 15 23 13 39 270 -71 -33 22 44 -32 53 50 -34 10 54 -32 4 14
123 0 0 -33 55 40 15 23 29 38 270 -71 -34 9 41 -33 41 35 -34 56 34 -32 53 24
124 0 0 -34 39 55 15 23 43 37 270 -71 -34 53 35 -34 26 12 -35 39 17 -33 39 17
125 0 0 -35 21 19 15 23 57 36 270 -70 -35 34 39 -35 7 55 -36 19 17 -34 22 10
126 0 0 -36 0 3 15 24 11 35 270 -70 -36 13 6 -35 46 57 -36 56 45 -35 2 15
127 0 0 -36 36 20 15 24 23 34 270 -69 -36 49 6 -36 23 30 -37 31 52 -35 39 46
128 0 0 -37 10 18 15 24 35 33 270 -69 -37 22 50 -36 57 44 -38 4 47 -36 14 52
129 0 0 -37 42 7 15 24 47 33 269 -69 -37 54 25 -37 29 47 -38 35 38 -36 47 42
130 0 0 -38 11 55 15 24 58 32 269 -68 -38 24 0 -37 59 47 -39 4 31 -37 18 27
131 0 0 -38 39 47 15 25 8 31 269 -68 -38 51 41 -38 27 51 -39 31 34 -37 47 11
132 0 0 -39 5 51 15 25 18 30 268 -67 -39 17 34 -38 54 6 -39 56 52 -38 14 3
133 0 0 -39 30 12 15 25 28 29 268 -67 -39 41 45 -39 18 36 -40 20 31 -38 39 8
134 0 0 -39 52 54 15 25 37 29 267 -66 -40 4 18 -39 41 28 -40 42 34 -39 2 30
135 0 0 -40 14 2 15 25 46 28 267 -66 -40 25 18 -40 2 44 -41 3 7 -39 24 16
136 0 0 -40 33 41 15 25 54 27 266 -65 -40 44 49 -40 22 30 -41 22 12 -39 44 29
137 0 0 -40 51 53 15 26 2 26 266 -65 -41 2 54 -40 40 50 -41 39 54 -40 3 13
138 0 0 -41 8 42 15 26 10 25 265 -64 -41 19 37 -40 57 45 -41 56 16 -40 20 31
139 0 0 -41 24 11 15 26 17 25 265 -64 -41 35 0 -41 13 21 -42 11 19 -40 36 27
140 0 0 -41 38 23 15 26 24 24 264 -63 -41 49 6 -41 27 38 -42 25 8 -40 51 3
141 0 0 -41 51 20 15 26 31 23 264 -63 -42 1 58 -41 40 39 -42 37 43 -41 4 21
142 0 0 -42 3 3 15 26 38 22 263 -62 -42 13 37 -41 52 27 -42 49 8 -41 16 25
143 0 0 -42 13 36 15 26 44 22 263 -62 -42 24 6 -42 3 4 -42 59 23 -41 27 16
144 0 0 -42 22 59 15 26 50 21 262 -61 -42 33 26 -42 12 31 -43 8 31 -41 36 55
145 0 0 -42 31 15 15 26 56 20 262 -61 -42 41 38 -42 20 50 -43 16 32 -41 45 25
146 0 0 -42 38 23 15 27 1 20 261 -60 -42 48 44 -42 28 1 -43 23 29 -41 52 46
147 0 0 -42 44 27 15 27 7 19 260 -60 -42 54 45 -42 34 7 -43 29 22 -41 59 1
148 0 0 -42 49 26 15 27 12 18 260 -59 -42 59 42 -42 39 9 -43 34 13 -42 4 9
149 0 0 -42 53 22 15 27 17 17 259 -59 -43 3 36 -42 43 6 -43 38 1 -42 8 12
150 0 0 -42 56 14 15 27 22 17 258 -58 -43 6 27 -42 46 0 -43 40 47 -42 11 11
151 0 0 -42 58 5 15 27 26 16 258 -58 -43 8 16 -42 47 51 -43 42 33 -42 13 6
152 0 0 -42 58 53 15 27 30 15 257 -57 -43 9 4 -42 48 40 -43 43 19 -42 13 58
153 0 0 -42 58 39 15 27 34 14 257 -57 -43 8 50 -42 48 27 -43 43 4 -42 13 46
154 0 0 -42 57 24 15 27 38 14 256 -56 -43 7 35 -42 47 12 -43 41 48 -42 12 31
155 0 0 -42 55 8 15 27 42 13 255 -56 -43 5 19 -42 44 55 -43 39 33 -42 10 13
156 0 0 -42 51 49 15 27 45 12 255 -55 -43 2 1 -42 41 36 -43 36 17 -42 6 52
157 0 0 -42 47 29 15 27 49 12 254 -55 -42 57 41 -42 37 14 -43 32 1 -42 2 27
158 0 0 -42 42 6 15 27 52 11 253 -54 -42 52 20 -42 31 50 -43 26 44 -41 56 58
159 0 0 -42 35 40 15 27 55 10 253 -54 -42 45 55 -42 25 23 -43 20 25 -41 50 25
160 0 0 -42 28 10 15 27 58 9 252 -53 -42 38 28 -42 17 51 -43 13 4 -41 42 47
161 0 0 -42 19 36 15 28 0 9 251 -52 -42 29 56 -42 9 15 -43 4 40 -41 34 3
162 0 0 -42 9 57 15 28 2 8 251 -52 -42 20 19 -41 59 33 -42 55 12 -41 24 12
163 0 0 -41 59 11 15 28 5 7 250 -51 -42 9 36 -41 48 44 -42 44 39 -41 13 12
Uncertainty in time = +/- 7 secs
Prediction of 2009 Jun 25.0
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