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Updated: 2013 FEB 27, 22:59 UT
Event Rank : 33
(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 2013 Mar 21 UT, the 24 km diameter asteroid (1555) Dejan will occult a 9.6 mag star in the constellation Taurus for observers along a fairly narrow path across the South Island of New Zealand, from Palmerston to Milford Sound (at low elevation), and across south-eastern Australia, crossing the coast near Batemans Bay, passing slightly south of Canberra, and crossing southern New South Wales in evening twilight.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.0 mag to 10.1 mag (the combined magnitude of the asteroid and the other component of the double star) for at most 1.1 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: .
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
177 23 41 -51 0 0 9 7 31 1 316 -26 176 57 55 177 49 20 175 12 40 ... .. ..
175 49 54 -50 0 0 9 7 31 2 318 -25 175 24 17 176 15 25 173 39 34 ... .. ..
174 15 8 -49 0 0 9 7 30 4 319 -25 173 49 36 174 40 32 172 5 12 ... .. ..
172 39 8 -48 0 0 9 7 29 5 320 -25 172 13 39 173 4 29 170 29 20 ... .. ..
171 1 41 -47 0 0 9 7 28 7 321 -24 170 36 12 171 27 3 168 51 44 173 8 13
169 22 33 -46 0 0 9 7 26 8 323 -23 168 56 59 169 47 59 167 12 9 171 29 18
167 41 27 -45 0 0 9 7 24 10 324 -23 167 15 45 168 7 0 165 30 15 169 48 43
165 58 4 -44 0 0 9 7 21 11 325 -22 165 32 10 166 23 49 163 45 42 168 6 11
164 12 4 -43 0 0 9 7 18 13 326 -21 163 45 53 164 38 5 161 58 7 166 21 24
162 23 3 -42 0 0 9 7 15 14 328 -20 161 56 29 162 49 24 160 7 1 164 33 59
160 30 31 -41 0 0 9 7 11 16 329 -19 160 3 28 160 57 20 158 11 50 162 43 33
158 33 54 -40 0 0 9 7 6 17 331 -18 158 6 16 159 1 18 156 11 53 160 49 37
156 32 32 -39 0 0 9 7 1 19 332 -17 156 4 8 157 0 39 154 6 19 158 51 35
Latitude Latitude Latitude Latitude
155 0 0 -38 16 0 9 6 57 20 334 -16 -38 29 33 -38 2 32 -39 25 18 -37 9 2
154 0 0 -37 48 18 9 6 54 21 334 -15 -38 1 45 -37 34 56 -38 57 4 -36 41 48
153 0 0 -37 21 15 9 6 51 22 335 -14 -37 34 37 -37 7 59 -38 29 31 -36 15 14
152 0 0 -36 54 53 9 6 47 22 336 -14 -37 8 9 -36 41 43 -38 2 39 -35 49 19
151 0 0 -36 29 12 9 6 44 23 337 -13 -36 42 23 -36 16 7 -37 36 29 -35 24 4
150 0 0 -36 4 12 9 6 41 24 338 -12 -36 17 17 -35 51 12 -37 11 1 -34 59 29
149 0 0 -35 39 54 9 6 37 25 339 -11 -35 52 54 -35 26 59 -36 46 17 -34 35 35
148 0 0 -35 16 19 9 6 34 25 339 -11 -35 29 14 -35 3 29 -36 22 15 -34 12 23
147 0 0 -34 53 26 9 6 30 26 340 -10 -35 6 16 -34 40 40 -35 58 57 -33 49 53
146 0 0 -34 31 16 9 6 27 27 341 -9 -34 44 2 -34 18 35 -35 36 23 -33 28 5
145 0 0 -34 9 49 9 6 23 27 342 -8 -34 22 31 -33 57 13 -35 14 34 -33 7 0
144 0 0 -33 49 7 9 6 19 28 343 -8 -34 1 44 -33 36 34 -34 53 29 -32 46 37
143 0 0 -33 29 8 9 6 15 28 344 -7 -33 41 41 -33 16 39 -34 33 9 -32 26 58
142 0 0 -33 9 53 9 6 11 29 345 -6 -33 22 22 -32 57 29 -34 13 34 -32 8 2
141 0 0 -32 51 24 9 6 8 29 346 -5 -33 3 49 -32 39 2 -33 54 45 -31 49 50
140 0 0 -32 33 38 9 6 3 30 347 -4 -32 46 0 -32 21 21 -33 36 41 -31 32 22
139 0 0 -32 16 38 9 5 59 30 348 -3 -32 28 57 -32 4 24 -33 19 23 -31 15 38
138 0 0 -32 0 23 9 5 55 31 349 -2 -32 12 39 -31 48 12 -33 2 52 -30 59 38
137 0 0 -31 44 54 9 5 51 31 350 -2 -31 57 6 -31 32 46 -32 47 6 -30 44 23
136 0 0 -31 30 10 9 5 47 31 351 -1 -31 42 19 -31 18 5 -32 32 7 -30 29 53
Uncertainty in time = +/- 5 secs
Prediction of 2013 Feb 28.0
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