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Updated: 2018 AUG 12, 17:21 UT
Event Rank : 79
(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 2018 Sep 10 UT, the 57.5 km diameter asteroid (307) Nike will occult a 12.5 mag star in the constellation Cetus for observers along a fairly narrow path across eastern Western Australia from east of Esperence to Derby.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.05 mag to 14.37 mag (the magnitude of the asteroid) for at most 22.9 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
125 37 37 -35 0 0 21 49 46 31 303 0 125 8 32 126 6 58 124 37 8 126 39 14 -1.07
125 16 15 -34 0 0 21 49 12 32 303 0 124 47 46 125 44 59 124 16 59 126 16 35 -1.07
124 57 15 -33 0 0 21 48 38 32 303 0 124 29 18 125 25 25 123 59 6 125 56 23 -1.07
124 40 27 -32 0 0 21 48 3 33 302 0 124 13 0 125 8 6 123 43 20 125 38 30 -1.07
124 25 43 -31 0 0 21 47 27 34 302 -1 123 58 45 124 52 55 123 29 35 125 22 46 -1.07
124 12 58 -30 0 0 21 46 51 35 302 -1 123 46 25 124 39 43 123 17 42 125 9 5 -1.07
124 2 5 -29 0 0 21 46 15 36 301 -1 123 35 55 124 28 25 123 7 38 124 57 20 -1.06
123 52 57 -28 0 0 21 45 38 36 301 -1 123 27 10 124 18 55 122 59 17 124 47 25 -1.06
123 45 31 -27 0 0 21 45 0 37 301 -1 123 20 4 124 11 8 122 52 33 124 39 15 -1.06
123 39 41 -26 0 0 21 44 22 38 300 -2 123 14 33 124 4 59 122 47 22 124 32 44 -1.05
123 35 24 -25 0 0 21 43 44 38 300 -2 123 10 34 124 0 23 122 43 41 124 27 49 -1.05
123 32 35 -24 0 0 21 43 5 39 299 -2 123 8 1 123 57 18 122 41 26 124 24 25 -1.05
123 31 11 -23 0 0 21 42 26 40 299 -2 123 6 53 123 55 39 122 40 33 124 22 30 -1.04
123 31 10 -22 0 0 21 41 46 40 298 -2 123 7 5 123 55 24 122 41 1 124 21 59 -1.04
123 32 28 -21 0 0 21 41 6 41 297 -2 123 8 36 123 56 29 122 42 45 124 22 50 1.03
123 35 3 -20 0 0 21 40 26 42 297 -2 123 11 23 123 58 52 122 45 45 124 25 0 1.03
123 38 53 -19 0 0 21 39 45 42 296 -2 123 15 23 124 2 31 122 49 56 124 28 26 1.02
123 43 55 -18 0 0 21 39 4 43 295 -2 123 20 35 124 7 24 122 55 19 124 33 8 1.02
123 50 8 -17 0 0 21 38 23 43 294 -2 123 26 57 124 13 28 123 1 50 124 39 2 1.01
123 57 30 -16 0 0 21 37 41 43 294 -2 123 34 27 124 20 42 123 9 28 124 46 7 1.01
124 6 0 -15 0 0 21 36 59 44 293 -2 123 43 3 124 29 4 123 18 13 124 54 22 1.00
124 15 36 -14 0 0 21 36 17 44 292 -2 123 52 46 124 38 34 123 28 2 125 3 44 1.00
124 26 17 -13 0 0 21 35 34 45 291 -2 124 3 32 124 49 9 123 38 54 125 14 14 0.99
124 38 2 -12 0 0 21 34 51 45 290 -2 124 15 22 125 0 50 123 50 49 125 25 49 0.99
124 50 51 -11 0 0 21 34 8 45 289 -2 124 28 15 125 13 35 124 3 46 125 38 30 0.98
125 4 43 -10 0 0 21 33 25 46 288 -2 124 42 10 125 27 23 124 17 44 125 52 15 0.98
125 19 37 - 9 0 0 21 32 41 46 287 -1 124 57 6 125 42 15 124 32 43 126 7 4 0.97
125 35 32 - 8 0 0 21 31 57 46 286 -1 125 13 3 125 58 9 124 48 42 126 22 56 0.97
Uncertainty in time = +/- 14 secs
Prediction of 2018 Aug 12.0
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