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Updated: 2015 OCT 31, 03:33 UT
Event Rank : 90
(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 2015 Dec 16 UT, the 44 km diameter asteroid (309) Fraternitas will occult a 12.4 mag star in the constellation Auriga for observers along a path across the North Island of New Zealand, from just south of Blenheim to Westport, and across southern Australia from directly over Sydney across central New South Wales, southern South Australia (including Port Augusta) and along the south coast of Western Australia, including Esperence and Albany.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.5 mag to 14.8 mag (the magnitude of the asteroid) for at most 3.4 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
-177 46 42 -48 0 0 15 6 0 8 330 -6 -176 55 4 -178 39 7 -176 1 8 -179 35 34
-179 14 6 -47 0 0 15 6 4 9 332 -7 -178 22 7 179 53 5 -177 27 51 178 56 9
179 15 18 -46 0 0 15 6 8 10 333 -9 -179 52 13 178 21 55 -178 57 29 177 24 18
177 41 9 -45 0 0 15 6 13 12 334 -10 178 34 19 176 47 1 179 29 42 175 48 31
176 3 1 -44 0 0 15 6 19 13 335 -12 176 57 4 175 7 55 177 53 18 174 8 17
174 20 23 -43 0 0 15 6 26 15 337 -13 175 15 33 173 24 3 176 12 52 172 22 59
172 32 37 -42 0 0 15 6 34 16 338 -15 173 29 12 171 34 45 174 27 51 170 31 51
170 38 55 -41 0 0 15 6 42 17 339 -17 171 37 15 169 39 5 172 37 37 168 33 54
168 38 14 -40 0 0 15 6 52 19 341 -18 169 38 48 167 35 56 170 41 17 166 27 49
Latitude Latitude Latitude Latitude
167 0 0 -39 13 57 15 7 1 20 342 -20 -38 45 10 -39 43 15 -38 15 12 -40 14 55
166 0 0 -38 47 2 15 7 7 21 343 -20 -38 18 33 -39 16 1 -37 48 53 -39 47 20
165 0 0 -38 21 2 15 7 12 21 344 -21 -37 52 50 -38 49 44 -37 23 28 -39 20 42
164 0 0 -37 55 57 15 7 18 22 345 -22 -37 28 2 -38 24 22 -36 58 55 -38 55 2
163 0 0 -37 31 47 15 7 24 23 346 -23 -37 4 7 -37 59 56 -36 35 15 -38 30 18
162 0 0 -37 8 32 15 7 30 23 347 -23 -36 41 5 -37 36 25 -36 12 29 -38 6 30
161 0 0 -36 46 10 15 7 36 24 348 -24 -36 18 57 -37 13 49 -35 50 34 -37 43 38
160 0 0 -36 24 42 15 7 42 24 348 -25 -35 57 43 -36 52 8 -35 29 33 -37 21 42
159 0 0 -36 4 8 15 7 48 25 349 -25 -35 37 21 -36 31 21 -35 9 24 -37 0 40
158 0 0 -35 44 28 15 7 55 25 350 -26 -35 17 52 -36 11 28 -34 50 6 -36 40 34
157 0 0 -35 25 41 15 8 1 26 351 -27 -34 59 16 -35 52 30 -34 31 41 -36 21 23
156 0 0 -35 7 47 15 8 8 26 352 -27 -34 41 32 -35 34 25 -34 14 8 -36 3 7
155 0 0 -34 50 46 15 8 15 26 353 -28 -34 24 41 -35 17 14 -33 57 27 -35 45 44
154 0 0 -34 34 38 15 8 21 27 354 -29 -34 8 42 -35 0 56 -33 41 37 -35 29 16
153 0 0 -34 19 22 15 8 28 27 355 -29 -33 53 35 -34 45 32 -33 26 38 -35 13 42
152 0 0 -34 4 59 15 8 35 27 356 -30 -33 39 19 -34 31 0 -33 12 31 -34 59 1
151 0 0 -33 51 28 15 8 42 28 357 -30 -33 25 56 -34 17 22 -32 59 15 -34 45 14
150 0 0 -33 38 49 15 8 49 28 358 -31 -33 13 24 -34 4 36 -32 46 50 -34 32 20
149 0 0 -33 27 2 15 8 56 28 359 -31 -33 1 43 -33 52 42 -32 35 15 -34 20 19
148 0 0 -33 16 7 15 9 3 28 360 -31 -32 50 54 -33 41 41 -32 24 32 -34 9 11
147 0 0 -33 6 4 15 9 10 28 1 -32 -32 40 56 -33 31 32 -32 14 40 -33 58 56
146 0 0 -32 56 52 15 9 17 29 2 -32 -32 31 49 -33 22 15 -32 5 38 -33 49 34
145 0 0 -32 48 32 15 9 24 29 3 -33 -32 23 33 -33 13 51 -31 57 26 -33 41 4
144 0 0 -32 41 3 15 9 31 29 4 -33 -32 16 9 -33 6 18 -31 50 5 -33 33 27
143 0 0 -32 34 26 15 9 38 29 5 -33 -32 9 35 -32 59 37 -31 43 35 -33 26 42
142 0 0 -32 28 40 15 9 45 29 6 -33 -32 3 51 -32 53 48 -31 37 55 -33 20 50
141 0 0 -32 23 45 15 9 52 29 7 -34 -31 58 59 -32 48 51 -31 33 5 -33 15 49
140 0 0 -32 19 41 15 9 59 29 7 -34 -31 54 58 -32 44 45 -31 29 5 -33 11 41
139 0 0 -32 16 29 15 10 7 29 8 -34 -31 51 47 -32 41 31 -31 25 56 -33 8 26
138 0 0 -32 14 8 15 10 14 29 9 -34 -31 49 27 -32 39 9 -31 23 37 -33 6 2
137 0 0 -32 12 38 15 10 21 28 10 -34 -31 47 57 -32 37 38 -31 22 9 -33 4 30
136 0 0 -32 11 59 15 10 28 28 11 -34 -31 47 19 -32 36 59 -31 21 30 -33 3 51
135 0 0 -32 12 11 15 10 35 28 12 -35 -31 47 31 -32 37 11 -31 21 42 -33 4 4
134 0 0 -32 13 15 15 10 42 28 13 -35 -31 48 34 -32 38 15 -31 22 44 -33 5 9
133 0 0 -32 15 9 15 10 48 28 14 -35 -31 50 27 -32 40 11 -31 24 37 -33 7 6
132 0 0 -32 17 55 15 10 55 27 15 -35 -31 53 12 -32 42 59 -31 27 19 -33 9 55
131 0 0 -32 21 33 15 11 2 27 16 -34 -31 56 47 -32 46 38 -31 30 53 -33 13 37
130 0 0 -32 26 2 15 11 9 27 17 -34 -32 1 13 -32 51 10 -31 35 16 -33 18 11
129 0 0 -32 31 22 15 11 15 27 18 -34 -32 6 31 -32 56 33 -31 40 31 -33 23 38
128 0 0 -32 37 34 15 11 22 26 19 -34 -32 12 39 -33 2 49 -31 46 36 -33 29 57
127 0 0 -32 44 37 15 11 28 26 20 -34 -32 19 39 -33 9 56 -31 53 32 -33 37 10
126 0 0 -32 52 33 15 11 35 25 20 -34 -32 27 30 -33 17 56 -32 1 18 -33 45 15
125 0 0 -33 1 20 15 11 41 25 21 -34 -32 36 12 -33 26 49 -32 9 56 -33 54 13
124 0 0 -33 11 0 15 11 47 25 22 -33 -32 45 47 -33 36 34 -32 19 25 -34 4 4
123 0 0 -33 21 31 15 11 54 24 23 -33 -32 56 13 -33 47 12 -32 29 45 -34 14 48
122 0 0 -33 32 56 15 12 0 24 24 -33 -33 7 30 -33 58 42 -32 40 56 -34 26 27
121 0 0 -33 45 12 15 12 6 23 25 -32 -33 19 40 -34 11 6 -32 52 59 -34 38 58
120 0 0 -33 58 22 15 12 11 23 26 -32 -33 32 42 -34 24 23 -33 5 53 -34 52 24
119 0 0 -34 12 24 15 12 17 22 26 -32 -33 46 37 -34 38 34 -33 19 40 -35 6 44
118 0 0 -34 27 20 15 12 23 21 27 -31 -34 1 24 -34 53 39 -33 34 18 -35 21 59
117 0 0 -34 43 9 15 12 28 21 28 -31 -34 17 3 -35 9 37 -33 49 49 -35 38 8
116 0 0 -34 59 51 15 12 33 20 29 -30 -34 33 36 -35 26 30 -34 6 11 -35 55 11
115 0 0 -35 17 27 15 12 39 20 29 -30 -34 51 2 -35 44 17 -34 23 27 -36 13 11
114 0 0 -35 35 58 15 12 44 19 30 -29 -35 9 21 -36 2 59 -34 41 35 -36 32 5
113 0 0 -35 55 22 15 12 48 18 31 -29 -35 28 34 -36 22 35 -35 0 36 -36 51 56
112 0 0 -36 15 41 15 12 53 17 32 -28 -35 48 41 -36 43 7 -35 20 31 -37 12 42
111 0 0 -36 36 55 15 12 58 17 32 -27 -36 9 42 -37 4 35 -35 41 18 -37 34 25
110 0 0 -36 59 4 15 13 2 16 33 -27 -36 31 37 -37 26 58 -36 2 59 -37 57 4
Uncertainty in time = +/- 3 secs
Prediction of 2015 Oct 31.0
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