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Updated: 2013 JUL 05, 16:18 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 2013 Aug 25 UT, the 105 km diameter asteroid (387) Aquitania will occult a 12.5 mag star in the constellation Sagittarius for observers along a path beginning near Lake Argyle in northern Western Australia. The path travels south-east and passes over Adelaide, and Warrnambool and then over Tasmania.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.2 mag to 10.7 mag (the magnitude of the asteroid) for at most 13.5 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
125 18 7 -11 0 0 13 32 54 70 239 -59 124 45 41 125 50 42 124 27 35 126 9 1
125 40 7 -12 0 0 13 33 10 70 242 -59 125 7 27 126 12 56 124 49 13 126 31 22
126 2 48 -13 0 0 13 33 25 70 244 -59 125 29 54 126 35 52 125 11 32 126 54 27
126 26 13 -14 0 0 13 33 41 70 247 -60 125 53 3 126 59 33 125 34 32 127 18 17
126 50 24 -15 0 0 13 33 56 70 250 -60 126 16 57 127 24 1 125 58 17 127 42 55
127 15 23 -16 0 0 13 34 12 70 253 -61 126 41 37 127 49 19 126 22 47 128 8 23
127 41 12 -17 0 0 13 34 28 70 256 -61 127 7 7 128 15 28 126 48 7 128 34 44
128 7 55 -18 0 0 13 34 43 69 259 -61 127 33 29 128 42 32 127 14 17 129 2 0
128 35 34 -19 0 0 13 34 59 69 261 -62 128 0 46 129 10 34 127 41 22 129 30 15
129 4 13 -20 0 0 13 35 15 69 264 -62 128 29 1 129 39 37 128 9 23 129 59 32
129 33 53 -21 0 0 13 35 31 68 266 -62 128 58 16 130 9 44 128 38 24 130 29 54
130 4 41 -22 0 0 13 35 47 68 269 -62 129 28 36 130 40 59 129 8 30 131 1 25
Latitude Latitude Latitude Latitude
131 0 0 -23 42 29 13 36 14 67 272 -62 -24 48 20 -22 35 27 -25 24 44 -21 57 22
132 0 0 -25 26 28 13 36 42 66 276 -63 -26 29 39 -24 22 15 -27 4 36 -23 45 48
133 0 0 -27 3 41 13 37 8 64 278 -63 -28 4 26 -26 2 0 -28 38 5 -25 27 2
134 0 0 -28 34 45 13 37 33 63 280 -63 -29 33 18 -27 35 21 -30 5 45 -27 1 43
135 0 0 -30 0 11 13 37 56 62 282 -62 -30 56 44 -29 2 53 -31 28 5 -28 30 27
136 0 0 -31 20 29 13 38 18 61 284 -62 -32 15 12 -30 25 5 -32 45 33 -29 53 45
137 0 0 -32 36 3 13 38 38 60 285 -62 -33 29 4 -31 42 24 -33 58 30 -31 12 4
138 0 0 -33 47 15 13 38 58 58 286 -62 -34 38 43 -32 55 12 -35 7 18 -32 25 48
139 0 0 -34 54 26 13 39 16 57 286 -61 -35 44 28 -34 3 52 -36 12 16 -33 35 18
140 0 0 -35 57 53 13 39 33 56 287 -61 -36 46 36 -35 8 41 -37 13 40 -34 40 55
141 0 0 -36 57 52 13 39 50 55 287 -61 -37 45 21 -36 9 57 -38 11 45 -35 42 54
142 0 0 -37 54 39 13 40 6 54 288 -60 -38 40 59 -37 7 54 -39 6 45 -36 41 31
143 0 0 -38 48 25 13 40 20 53 288 -60 -39 33 41 -38 2 46 -39 58 53 -37 37 1
144 0 0 -39 39 23 13 40 35 52 288 -59 -40 23 40 -38 54 45 -40 48 18 -38 29 36
145 0 0 -40 27 44 13 40 48 51 288 -59 -41 11 5 -39 44 3 -41 35 12 -39 19 26
146 0 0 -41 13 37 13 41 1 50 288 -58 -41 56 5 -40 30 50 -42 19 44 -40 6 43
147 0 0 -41 57 11 13 41 13 49 288 -58 -42 38 50 -41 15 14 -43 2 2 -40 51 36
148 0 0 -42 38 34 13 41 25 48 287 -57 -43 19 27 -41 57 24 -43 42 14 -41 34 13
149 0 0 -43 17 54 13 41 36 47 287 -57 -43 58 4 -42 37 28 -44 20 26 -42 14 43
150 0 0 -43 55 17 13 41 47 46 287 -56 -44 34 46 -43 15 33 -44 56 46 -42 53 11
151 0 0 -44 30 50 13 41 58 45 286 -56 -45 9 41 -43 51 45 -45 31 20 -43 29 46
152 0 0 -45 4 39 13 42 7 44 286 -55 -45 42 53 -44 26 11 -46 4 12 -44 4 32
153 0 0 -45 36 48 13 42 17 43 286 -55 -46 14 29 -44 58 55 -46 35 29 -44 37 36
Uncertainty in time = +/- 4 secs
Prediction of 2013 Jul 4.0
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