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Updated: 2011 SEP 24, 03:07 UT
Event Rank : 16
(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 Nov 19 UT, the 21 km diameter asteroid (3901) Nanjingdaxue will occult a 9.3 mag star in the constellation Perseus for observers along a narrow but quite uncertain path across Australia centred from just north of Brisbane to Longreach, and in Western Australia near Port Hedland, Karratha and Broome. In Queensland, Rockhampton is just outside the 1-sigma uncertainty area.
In the case of an occultation, the combined light of the asteroid and the star will drop by 8.2 mag to 17.5 mag (the magnitude of the asteroid) for at most 1.3 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, 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
163 4 23 -33 0 0 15 48 17 14 335 -23 163 23 47 162 44 50 166 0 29 159 54 51
161 40 56 -32 0 0 15 48 22 15 336 -25 162 0 47 161 20 54 164 40 48 158 26 14
160 13 4 -31 0 0 15 48 27 17 337 -26 160 33 28 159 52 28 163 17 27 156 52 6
158 40 11 -30 0 0 15 48 34 18 338 -28 159 1 15 158 18 53 161 50 2 155 11 33
157 1 30 -29 0 0 15 48 41 20 339 -29 157 23 24 156 39 22 160 17 58 153 23 23
155 16 4 -28 0 0 15 48 50 21 340 -31 155 38 58 154 52 52 158 40 37 151 25 57
153 22 30 -27 0 0 15 48 59 23 341 -33 153 46 40 152 57 58 156 57 6 149 16 51
151 18 57 -26 0 0 15 49 10 24 343 -35 151 44 46 150 52 41 155 6 18 146 52 24
Latitude Latitude Latitude Latitude
150 0 0 -25 24 28 15 49 17 25 344 -36 -25 12 36 -25 36 25 -23 35 59 -27 19 22
149 0 0 -24 58 54 15 49 22 26 344 -37 -24 47 8 -25 10 44 -23 11 25 -26 52 37
148 0 0 -24 34 33 15 49 28 26 345 -38 -24 22 53 -24 46 16 -22 48 0 -26 27 9
147 0 0 -24 11 24 15 49 34 27 346 -39 -23 59 51 -24 23 1 -22 25 44 -26 2 59
146 0 0 -23 49 27 15 49 39 27 347 -39 -23 37 59 -24 0 58 -22 4 36 -25 40 3
145 0 0 -23 28 40 15 49 45 28 348 -40 -23 17 18 -23 40 6 -21 44 35 -25 18 23
144 0 0 -23 9 4 15 49 51 29 348 -41 -22 57 46 -23 20 25 -21 25 42 -24 57 56
143 0 0 -22 50 36 15 49 57 29 349 -42 -22 39 24 -23 1 53 -21 7 55 -24 38 42
142 0 0 -22 33 18 15 50 3 29 350 -42 -22 22 9 -22 44 30 -20 51 13 -24 20 40
141 0 0 -22 17 7 15 50 9 30 351 -43 -22 6 3 -22 28 16 -20 35 37 -24 3 49
140 0 0 -22 2 4 15 50 15 30 352 -44 -21 51 3 -22 13 9 -20 21 6 -23 48 9
139 0 0 -21 48 8 15 50 22 31 353 -44 -21 37 11 -21 59 10 -20 7 39 -23 33 40
138 0 0 -21 35 19 15 50 28 31 354 -45 -21 24 24 -21 46 17 -19 55 16 -23 20 19
137 0 0 -21 23 35 15 50 34 31 354 -45 -21 12 44 -21 34 31 -19 43 57 -23 8 8
136 0 0 -21 12 58 15 50 40 31 355 -46 -21 2 8 -21 23 51 -19 33 41 -22 57 5
135 0 0 -21 3 25 15 50 47 32 356 -47 -20 52 38 -21 14 16 -19 24 28 -22 47 10
134 0 0 -20 54 58 15 50 53 32 357 -47 -20 44 13 -21 5 47 -19 16 18 -22 38 23
133 0 0 -20 47 35 15 50 59 32 358 -47 -20 36 52 -20 58 22 -19 9 10 -22 30 44
132 0 0 -20 41 17 15 51 6 32 359 -48 -20 30 35 -20 52 3 -19 3 5 -22 24 11
131 0 0 -20 36 4 15 51 12 32 360 -48 -20 25 23 -20 46 48 -18 58 1 -22 18 45
130 0 0 -20 31 54 15 51 19 32 1 -49 -20 21 14 -20 42 37 -18 54 0 -22 14 26
129 0 0 -20 28 48 15 51 25 32 2 -49 -20 18 9 -20 39 31 -18 51 0 -22 11 13
128 0 0 -20 26 47 15 51 31 32 3 -49 -20 16 8 -20 37 29 -18 49 3 -22 9 7
127 0 0 -20 25 49 15 51 38 32 4 -49 -20 15 10 -20 36 31 -18 48 6 -22 8 7
126 0 0 -20 25 55 15 51 44 32 4 -49 -20 15 16 -20 36 37 -18 48 12 -22 8 14
125 0 0 -20 27 5 15 51 51 32 5 -50 -20 16 26 -20 37 47 -18 49 20 -22 9 26
124 0 0 -20 29 19 15 51 57 32 6 -50 -20 18 39 -20 40 1 -18 51 29 -22 11 46
123 0 0 -20 32 36 15 52 3 32 7 -50 -20 21 56 -20 43 20 -18 54 40 -22 15 11
122 0 0 -20 36 58 15 52 10 32 8 -50 -20 26 17 -20 47 43 -18 58 52 -22 19 43
121 0 0 -20 42 24 15 52 16 31 9 -50 -20 31 42 -20 53 10 -19 4 7 -22 25 22
120 0 0 -20 48 55 15 52 22 31 10 -50 -20 38 11 -20 59 42 -19 10 25 -22 32 8
119 0 0 -20 56 30 15 52 28 31 11 -50 -20 45 44 -21 7 19 -19 17 44 -22 40 1
118 0 0 -21 5 10 15 52 35 31 12 -50 -20 54 22 -21 16 1 -19 26 6 -22 49 2
117 0 0 -21 14 55 15 52 41 30 12 -49 -21 4 5 -21 25 49 -19 35 32 -22 59 11
116 0 0 -21 25 46 15 52 47 30 13 -49 -21 14 54 -21 36 42 -19 46 0 -23 10 28
115 0 0 -21 37 43 15 52 53 29 14 -49 -21 26 48 -21 48 42 -19 57 32 -23 22 53
114 0 0 -21 50 47 15 52 59 29 15 -49 -21 39 48 -22 1 49 -20 10 8 -23 36 29
113 0 0 -22 4 57 15 53 5 29 16 -48 -21 53 55 -22 16 2 -20 23 48 -23 51 13
112 0 0 -22 20 14 15 53 10 28 17 -48 -22 9 8 -22 31 24 -20 38 33 -24 7 9
111 0 0 -22 36 40 15 53 16 28 17 -47 -22 25 30 -22 47 53 -20 54 23 -24 24 15
110 0 0 -22 54 13 15 53 22 27 18 -47 -22 42 59 -23 5 31 -21 11 19 -24 42 34
109 0 0 -23 12 56 15 53 27 26 19 -47 -23 1 37 -23 24 19 -21 29 20 -25 2 5
108 0 0 -23 32 49 15 53 33 26 20 -46 -23 21 25 -23 44 17 -21 48 29 -25 22 49
107 0 0 -23 53 52 15 53 38 25 20 -45 -23 42 23 -24 5 26 -22 8 45 -25 44 48
106 0 0 -24 16 7 15 53 44 24 21 -45 -24 4 32 -24 27 46 -22 30 9 -26 8 2
105 0 0 -24 39 33 15 53 49 24 22 -44 -24 27 52 -24 51 19 -22 52 42 -26 32 32
104 0 0 -25 4 13 15 53 54 23 22 -44 -24 52 25 -25 16 5 -23 16 24 -26 58 19
Uncertainty in time = +/- 6 secs
Prediction of 2011 Sep 24.0
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