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Updated: 2016 Mar 26, 00:25 UT
Event Rank : 85
(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 Apr 14 UT, the 66 km diameter asteroid (516) Amherstia will occult a 11.9 mag star in the constellation Scorpius for observers along a path across Northern Territory, south-western Queensland, western and southern New South Wales and north-eastern Victoria.
In the case of an occultation, the combined light of the asteroid and the star will drop by only 0.5 mag to 11.2 mag (the magnitude of the asteroid) for at most 10.6 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, astrometry for the asteroid kindly provided by 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.
Occultation of UCAC4-230-113850 by 516 Amherstia on 2016 Apr 14
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
133 12 16 -10 0 0 19 28 24 52 202 -26 132 51 8 133 33 28 132 26 18 133 58 36 -0.50
133 31 48 -11 0 0 19 28 41 53 203 -26 133 10 31 133 53 10 132 45 30 134 18 29 -0.50
133 52 9 -12 0 0 19 28 58 54 204 -25 133 30 41 134 13 41 133 5 29 134 39 13 -0.50
134 13 22 -13 0 0 19 29 16 54 205 -25 133 51 43 134 35 5 133 26 18 135 0 50 -0.50
134 35 28 -14 0 0 19 29 34 55 206 -25 134 13 38 134 57 24 133 47 59 135 23 24 -0.50
134 58 32 -15 0 0 19 29 52 56 207 -24 134 36 29 135 20 40 134 10 35 135 46 56 -0.51
135 22 35 -16 0 0 19 30 10 56 209 -24 135 0 18 135 44 57 134 34 8 136 11 30 -0.51
135 47 40 -17 0 0 19 30 28 57 210 -23 135 25 9 136 10 18 134 58 41 136 37 8 -0.51
136 13 51 -18 0 0 19 30 47 58 211 -23 135 51 4 136 36 45 135 24 19 137 3 55 -0.51
136 41 12 -19 0 0 19 31 6 58 213 -22 136 18 8 137 4 24 135 51 3 137 31 54 -0.51
137 9 47 -20 0 0 19 31 26 59 214 -22 136 46 24 137 33 17 136 18 57 138 1 10 -0.52
137 39 39 -21 0 0 19 31 45 59 215 -22 137 15 56 138 3 29 136 48 7 138 31 46 -0.52
138 10 54 -22 0 0 19 32 5 60 217 -21 137 46 50 138 35 5 137 18 36 139 3 49 -0.52
139 0 0 -23 29 5 19 32 35 60 219 -20 -24 12 3 -22 45 25 -25 1 57 -21 53 0 -0.52
140 0 0 -25 10 6 19 33 9 61 222 -19 -25 50 59 -24 28 38 -26 38 32 -23 38 54 -0.53
141 0 0 -26 43 30 19 33 42 61 225 -18 -27 22 34 -26 3 57 -28 8 1 -25 16 34 -0.53
142 0 0 -28 10 10 19 34 13 62 228 -17 -28 47 35 -27 32 17 -29 31 12 -26 46 58 -0.53
143 0 0 -29 30 46 19 34 42 62 230 -16 -30 6 45 -28 54 23 -30 48 43 -28 10 55 -0.54
144 0 0 -30 45 57 19 35 10 62 233 -15 -31 20 38 -30 10 54 -32 1 7 -29 29 4 -0.54
145 0 0 -31 56 13 19 35 37 62 235 -15 -32 29 44 -31 22 23 -33 8 53 -30 42 0 -0.54
146 0 0 -33 2 1 19 36 2 61 237 -14 -33 34 28 -32 29 16 -34 12 24 -31 50 13 -0.54
147 0 0 -34 3 44 19 36 27 61 239 -13 -34 35 13 -33 31 58 -35 12 2 -32 54 8 -0.54
148 0 0 -35 1 42 19 36 50 61 241 -12 -35 32 18 -34 30 50 -36 8 6 -33 54 6 -0.55
149 0 0 -35 56 13 19 37 12 61 242 -11 -36 26 1 -35 26 11 -37 0 53 -34 50 27 -0.55
150 0 0 -36 47 33 19 37 34 60 244 -10 -37 16 36 -36 18 17 -37 50 37 -35 43 28 -0.55
151 0 0 -37 35 55 19 37 54 60 245 -10 -38 4 17 -37 7 21 -38 37 31 -36 33 23 -0.55
152 0 0 -38 21 33 19 38 14 59 246 -9 -38 49 17 -37 53 37 -39 21 46 -37 20 26 -0.55
Uncertainty in time = +/- 7 secs
Prediction of 2016 Mar 26.0
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