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Updated: 2016 AUG 25, 22:46 UT
Event Rank : 100
(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 2016 Sep 13 UT, the 208 km diameter asteroid (85) Io will occult a 9.8 mag star in the constellation Aquarius for observers along a path across north-western Western Australia, at very low elevation.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.29 mag to 10.70 mag (the magnitude of the asteroid) for at most 32.3 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, astrometry for the asteroid kindly provided by Bill Owen, astrometry for the asteroid kindly provided by the IAU Minor Planet Center.
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 Limit1 Path Limit2 Error Limit1 Error Limit2 Alt
E. Longitude Latitude U.T. Alt Az Alt Crn
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
119 18 59 - 5 53 9 18 11 2 17 271 -57 122 53 4 - 5 51 44 116 21 31 - 5 53 55 123 37 46 - 5 51 22 115 52 11 - 5 54 0 -3.24
119 23 35 - 6 23 26 18 11 10 17 271 -57 122 59 36 - 6 21 59 116 25 1 - 6 24 13 123 44 50 - 6 21 37 115 55 32 - 6 24 19 -3.25
119 29 8 - 6 53 44 18 11 19 17 271 -57 123 7 24 - 6 52 15 116 29 17 - 6 54 32 123 53 15 - 6 51 52 115 59 38 - 6 54 38 -3.26
119 35 40 - 7 24 3 18 11 28 17 271 -56 123 16 29 - 7 22 31 116 34 22 - 7 24 52 124 3 4 - 7 22 7 116 4 30 - 7 24 58 -3.27
119 43 11 - 7 54 22 18 11 36 16 271 -56 123 26 57 - 7 52 48 116 40 16 - 7 55 13 124 14 22 - 7 52 23 116 10 11 - 7 55 20 -3.27
119 51 45 - 8 24 43 18 11 45 16 271 -56 123 38 51 - 8 23 5 116 47 0 - 8 25 36 124 27 15 - 8 22 39 116 16 40 - 8 25 42 -3.28
120 1 23 - 8 55 5 18 11 54 16 272 -56 123 52 18 - 8 53 23 116 54 37 - 8 56 0 124 41 49 - 8 52 56 116 24 0 - 8 56 7 -3.29
120 12 9 - 9 25 28 18 12 2 16 272 -55 124 7 23 - 9 23 42 117 3 7 - 9 26 26 124 58 12 - 9 23 14 116 32 12 - 9 26 33 -3.30
120 24 6 - 9 55 53 18 12 11 16 272 -55 124 24 15 - 9 54 2 117 12 33 - 9 56 53 125 16 34 - 9 53 32 116 41 17 - 9 57 0 -3.31
120 37 17 -10 26 19 18 12 20 15 272 -55 124 43 2 -10 24 22 117 22 57 -10 27 22 125 37 8 -10 23 51 116 51 19 -10 27 30 -3.32
120 51 48 -10 56 47 18 12 28 15 272 -54 125 3 58 -10 54 44 117 34 21 -10 57 53 126 0 9 -10 54 10 117 2 18 -10 58 1 -3.32
121 7 43 -11 27 17 18 12 37 15 272 -54 125 27 16 -11 25 6 117 46 48 -11 28 26 126 25 58 -11 24 30 117 14 19 -11 28 34 -3.33
121 25 8 -11 57 48 18 12 45 14 272 -54 125 53 14 -11 55 28 118 0 22 -11 59 1 126 54 59 -11 54 49 117 27 23 -11 59 10 -3.34
121 44 10 -12 28 21 18 12 54 14 272 -53 126 22 19 -12 25 51 118 15 6 -12 29 38 127 27 51 -12 25 8 117 41 34 -12 29 48 -3.35
122 4 57 -12 58 56 18 13 3 14 272 -53 126 55 1 -12 56 13 118 31 4 -13 0 18 128 5 23 -12 55 25 117 56 55 -13 0 28 -3.36
122 27 39 -13 29 32 18 13 11 13 272 -52 127 32 8 -13 26 35 118 48 21 -13 31 0 128 48 55 -13 25 41 118 13 32 -13 31 10 -3.37
122 52 27 -14 0 10 18 13 20 13 272 -52 128 14 47 -13 56 55 119 7 1 -14 1 44 129 40 37 -13 55 51 118 31 28 -14 1 55 -3.37
123 19 38 -14 30 50 18 13 29 12 272 -51 129 4 47 -14 27 12 119 27 12 -14 32 31 130 44 43 -14 25 53 118 50 49 -14 32 43 -3.38
123 49 28 -15 1 32 18 13 37 12 272 -51 130 5 26 -14 57 22 119 49 1 -15 3 21 132 11 58 -14 55 36 119 11 42 -15 3 34 -3.39
124 22 21 -15 32 14 18 13 46 11 272 -50 131 24 4 -15 27 17 120 12 35 -15 34 13 135 47 55 -15 23 11 119 34 14 -15 34 27 -3.40
124 58 48 -16 2 58 18 13 55 10 272 -49 133 28 16 -15 56 31 120 38 5 -16 5 8 ... .. .. .. .. .. 119 58 34 -16 5 23 -3.42
125 39 31 -16 33 42 18 14 3 10 272 -48 ... .. .. .. .. .. 121 5 44 -16 36 5 ... .. .. .. .. .. 120 24 52 -16 36 22 -3.43
126 25 30 -17 4 26 18 14 12 9 272 -47 ... .. .. .. .. .. 121 35 45 -17 7 5 ... .. .. .. .. .. 120 53 21 -17 7 24 -3.45
127 18 16 -17 35 8 18 14 21 8 272 -47 ... .. .. .. .. .. 122 8 27 -17 38 8 ... .. .. .. .. .. 121 24 15 -17 38 28 -3.49
128 20 20 -18 5 46 18 14 29 7 271 -45 ... .. .. .. .. .. 122 44 13 -18 9 12 ... .. .. .. .. .. 121 57 55 -18 9 35 -3.54
129 36 34 -18 36 15 18 14 38 6 271 -44 ... .. .. .. .. .. 123 23 32 -18 40 19 ... .. .. .. .. .. 122 34 43 -18 40 44 -3.64
131 19 21 -19 6 22 18 14 47 4 270 -42 ... .. .. .. .. .. 124 7 5 -19 11 27 ... .. .. .. .. .. 123 15 11 -19 11 55 -3.93
135 11 42 -19 34 23 18 14 55 0 269 -39 ... .. .. .. .. .. 124 55 47 -19 42 36 ... .. .. .. .. .. 124 0 1 -19 43 8 -16.32
.. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. 125 51 1 -20 13 45 ... .. .. .. .. .. 124 50 12 -20 14 22 ....
.. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. 126 54 57 -20 44 51 ... .. .. .. .. .. 125 47 10 -20 45 35 ....
.. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. 128 11 27 -21 15 50 ... .. .. .. .. .. 126 53 16 -21 16 45 ....
.. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. 129 49 4 -21 46 35 ... .. .. .. .. .. 128 12 44 -21 47 49 ....
.. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. 132 17 44 -22 16 35 ... .. .. .. .. .. 129 55 9 -22 18 36 ....
Uncertainty in time = +/- 3 secs
Prediction of 2016 Aug 25.0
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