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Updated: 2017 Sep 14, 22:05 UT
Event Rank : 62
(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 Oct 31 UT, the 30 km diameter asteroid (920) Rogeria will occult a 8.7 mag star in the constellation Pisces for observers along a somewhat uncertain path across Queenland, north-western South Australia and south-eastern West Australia, passing near Townsville.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.71 mag to 14.40 mag (the magnitude of the asteroid) for at most 2.6 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, 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.
Occultation of HIP 9791 by 920 Rogeria on 2017 Oct 31
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
119 4 5 -37 0 0 17 48 18 37 315 -31 118 41 11 119 27 8 117 59 49 120 9 25 1.34
120 13 49 -36 0 0 17 48 5 37 313 -32 119 50 48 120 36 58 119 9 15 121 19 29 1.33
121 25 27 -35 0 0 17 47 51 37 312 -32 121 2 17 121 48 45 120 20 30 122 31 34 1.33
122 39 9 -34 0 0 17 47 38 37 310 -32 122 15 48 123 2 39 121 33 41 123 45 51 1.33
123 55 6 -33 0 0 17 47 24 37 308 -32 123 31 31 124 18 51 122 49 0 125 2 30 1.33
125 13 29 -32 0 0 17 47 10 36 306 -32 124 49 37 125 37 31 124 6 36 126 21 45 1.33
126 34 32 -31 0 0 17 46 56 36 305 -32 126 10 20 126 58 57 125 26 44 127 43 52 1.33
127 58 33 -30 0 0 17 46 41 36 303 -32 127 33 55 128 23 22 126 49 37 129 9 7 1.33
129 25 49 -29 0 0 17 46 26 35 301 -32 129 0 42 129 51 9 128 15 33 130 37 52 1.33
130 56 44 -28 0 0 17 46 11 35 300 -32 130 31 2 131 22 41 129 44 53 132 10 34 1.33
132 31 46 -27 0 0 17 45 56 34 298 -31 132 5 22 132 58 25 131 18 2 133 47 42 1.34
134 11 28 -26 0 0 17 45 40 33 296 -31 133 44 15 134 39 0 132 55 29 135 29 57 1.34
135 56 33 -25 0 0 17 45 24 32 294 -30 135 28 20 136 25 8 134 37 52 137 18 8 1.34
137 47 58 -24 0 0 17 45 8 31 293 -29 137 18 31 138 17 50 136 25 57 139 13 21 1.34
139 46 53 -23 0 0 17 44 52 30 291 -28 139 15 55 140 18 21 138 20 47 141 17 2 1.35
141 54 58 -22 0 0 17 44 35 28 289 -27 141 22 5 142 28 30 140 23 42 143 31 17 1.35
142 0 0 -21 57 45 17 44 34 28 289 -27 -21 42 52 -22 12 43 -21 16 1 -22 40 13 1.32
143 0 0 -21 31 22 17 44 26 28 289 -27 -21 16 36 -21 46 13 -20 49 58 -22 13 30 1.33
144 0 0 -21 6 1 17 44 19 27 288 -26 -20 51 22 -21 20 46 -20 24 55 -21 47 51 1.34
145 0 0 -20 41 43 17 44 12 26 287 -26 -20 27 10 -20 56 21 -20 0 54 -21 23 15 1.34
146 0 0 -20 18 26 17 44 5 25 287 -25 -20 3 59 -20 32 59 -19 37 53 -20 59 41 1.34
147 0 0 -19 56 11 17 43 58 25 286 -24 -19 41 49 -20 10 38 -19 15 53 -20 37 9 1.34
148 0 0 -19 34 57 17 43 51 24 285 -24 -19 20 40 -19 49 19 -18 54 53 -20 15 40 1.34
149 0 0 -19 14 44 17 43 45 23 285 -23 -19 0 32 -19 29 0 -18 34 53 -19 55 13 1.34
150 0 0 -18 55 31 17 43 39 22 284 -22 -18 41 24 -19 9 44 -18 15 54 -19 35 47 1.34
151 0 0 -18 37 20 17 43 33 21 284 -22 -18 23 16 -18 51 28 -17 57 54 -19 17 23 1.34
152 0 0 -18 20 8 17 43 28 20 283 -21 -18 6 9 -18 34 12 -17 40 54 -19 0 1 1.35
153 0 0 -18 3 57 17 43 22 20 283 -20 -17 50 2 -18 17 57 -17 24 53 -18 43 39 1.35
154 0 0 -17 48 46 17 43 17 19 282 -19 -17 34 54 -18 2 43 -17 9 51 -18 28 18 1.35
155 0 0 -17 34 35 17 43 12 18 282 -19 -17 20 46 -17 48 29 -16 55 49 -18 13 58 1.35
Uncertainty in time = +/- 4 secs
Prediction of 2017 Sep 14.0
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