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Updated: 2017 JUL 27, 20:13 UT
Event Rank : 48
(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 2017 Sep 17 UT, the 33 km diameter asteroid (916) America will occult a 10.2 mag star in the constellation Pisces for observers along a narrow path across Australia from Mt Gambier and Adelaide across south-east to north-west South Australia and across north-western Western Australia to Broome.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.26 mag to 13.40 mag (the magnitude of the asteroid) for at most 5.4 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.
This work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
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 Alt
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 Crn
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
148 2 59 -48 0 0 15 28 24 20 358 -40 148 24 4 147 41 51 149 28 16 146 36 50 1.02
147 22 41 -47 0 0 15 28 34 21 359 -42 147 43 29 147 1 50 148 46 49 145 57 41 1.02
146 41 50 -46 0 0 15 28 44 22 360 -43 147 2 23 146 21 15 148 4 54 145 17 54 1.02
146 0 26 -45 0 0 15 28 55 23 0 -44 146 20 44 145 40 5 147 22 31 144 37 29 1.02
145 18 27 -44 0 0 15 29 6 24 1 -45 145 38 31 144 58 20 146 39 37 143 56 24 1.02
144 35 52 -43 0 0 15 29 18 25 2 -46 144 55 44 144 15 57 145 56 12 143 14 39 1.02
143 52 39 -42 0 0 15 29 30 26 2 -47 144 12 20 143 32 55 145 12 13 142 32 11 1.02
143 8 47 -41 0 0 15 29 43 27 3 -48 143 28 17 142 49 13 144 27 39 141 49 0 1.02
142 24 13 -40 0 0 15 29 56 28 4 -49 142 43 35 142 4 49 143 42 28 141 5 4 1.02
141 38 58 -39 0 0 15 30 10 29 5 -50 141 58 11 141 19 42 142 56 38 140 20 22 1.02
140 52 58 -38 0 0 15 30 24 30 5 -52 141 12 4 140 33 49 142 10 9 139 34 51 1.02
140 6 12 -37 0 0 15 30 39 31 6 -53 140 25 11 139 47 9 141 22 56 138 48 30 1.02
139 18 38 -36 0 0 15 30 54 32 7 -54 139 37 32 138 59 41 140 35 0 138 1 18 1.02
138 30 14 -35 0 0 15 31 10 33 8 -55 138 49 3 138 11 21 139 46 16 137 13 11 1.02
137 40 57 -34 0 0 15 31 27 34 9 -56 137 59 43 137 22 8 138 56 44 136 24 9 1.02
136 50 46 -33 0 0 15 31 43 34 10 -57 137 9 28 136 31 59 138 6 21 135 34 7 1.02
135 59 37 -32 0 0 15 32 1 35 11 -59 136 18 18 135 40 52 137 15 4 134 43 5 1.02
135 7 27 -31 0 0 15 32 19 36 12 -60 135 26 7 134 48 43 136 22 51 133 50 58 1.02
134 14 15 -30 0 0 15 32 37 37 13 -61 134 32 55 133 55 31 135 29 38 132 57 44 1.02
133 19 56 -29 0 0 15 32 56 38 14 -62 133 38 38 133 1 11 134 35 23 132 3 20 1.02
132 24 28 -28 0 0 15 33 16 39 15 -63 132 43 11 132 5 40 133 40 3 131 7 41 1.01
131 27 46 -27 0 0 15 33 36 39 16 -64 131 46 32 131 8 54 132 43 32 130 10 44 1.01
130 29 46 -26 0 0 15 33 57 40 18 -66 130 48 37 130 10 50 131 45 49 129 12 25 1.01
129 30 24 -25 0 0 15 34 18 41 19 -67 129 49 20 129 11 22 130 46 48 128 12 39 1.01
128 29 34 -24 0 0 15 34 40 41 20 -68 128 48 37 128 10 26 129 46 24 127 11 20 1.01
127 27 12 -23 0 0 15 35 2 42 22 -69 127 46 23 127 7 56 128 44 33 126 8 23 1.01
126 23 12 -22 0 0 15 35 25 43 23 -70 126 42 32 126 3 46 127 41 10 125 3 41 1.00
125 17 26 -21 0 0 15 35 49 43 25 -71 125 36 58 124 57 49 126 36 7 123 57 7 1.00
124 9 48 -20 0 0 15 36 13 44 26 -72 124 29 32 123 49 57 125 29 19 122 48 33 1.00
123 0 8 -19 0 0 15 36 38 44 28 -73 123 20 7 122 40 2 124 20 36 121 37 50 1.00
121 48 18 -18 0 0 15 37 3 44 30 -74 122 8 34 121 27 55 123 9 52 120 24 47 1.00
120 34 7 -17 0 0 15 37 30 45 31 -75 120 54 42 120 13 24 121 56 55 119 9 13 1.00
119 17 22 -16 0 0 15 37 57 45 33 -75 119 38 19 118 56 17 120 41 35 117 50 53 0.99
117 57 50 -15 0 0 15 38 24 45 35 -76 118 19 11 117 36 19 119 23 40 116 29 32 0.99
Uncertainty in time = +/- 9 secs
Prediction of 2017 Jul 27.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
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[Asteroid Occultation Results]
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