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Updated: 2017 Oct 12, 20:08 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 2018 Jan 23 UT, the 150 km diameter asteroid (488) Kreusa will occult a 11.4 mag star in the constellation Aries for observers along a wide path across north-western West Australia, running from Shark Bay to Karratha, passing near Geraldton.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.03 mag to 13.20 mag (the magnitude of the asteroid) for at most 21.6 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. 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 TYC 1233-01013-1 by 488 Kreusa on 2018 Jan 23
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
110 45 38 -37 0 0 12 48 14 36 343 -10 111 49 12 109 42 36 112 12 13 109 20 2 0.69
111 3 20 -36 0 0 12 48 26 37 342 -11 112 6 14 110 0 58 112 29 1 109 38 39 0.69
111 21 29 -35 0 0 12 48 39 38 341 -12 112 23 46 110 19 45 112 46 19 109 57 38 0.69
111 40 6 -34 0 0 12 48 52 39 341 -13 112 41 47 110 38 56 113 4 8 110 17 2 0.69
111 59 9 -33 0 0 12 49 5 40 340 -13 113 0 19 110 58 31 113 22 28 110 36 49 0.69
112 18 40 -32 0 0 12 49 18 40 339 -14 113 19 19 111 18 32 113 41 18 110 57 1 0.69
112 38 38 -31 0 0 12 49 32 41 338 -15 113 38 50 111 38 58 114 0 39 111 17 37 0.69
112 59 5 -30 0 0 12 49 46 42 338 -16 113 58 52 111 59 51 114 20 31 111 38 38 0.69
113 20 0 -29 0 0 12 50 0 43 337 -17 114 19 24 112 21 9 114 40 55 112 0 6 0.70
113 41 25 -28 0 0 12 50 14 44 336 -18 114 40 27 112 42 55 115 1 51 112 21 59 0.70
114 3 19 -27 0 0 12 50 29 44 335 -18 115 2 3 113 5 9 115 23 19 112 44 20 0.70
114 25 44 -26 0 0 12 50 44 45 334 -19 115 24 10 113 27 51 115 45 21 113 7 8 0.70
114 48 40 -25 0 0 12 50 59 46 333 -20 115 46 52 113 51 2 116 7 57 113 30 25 0.70
115 12 8 -24 0 0 12 51 15 46 332 -21 116 10 7 114 14 43 116 31 8 113 54 11 0.70
115 36 10 -23 0 0 12 51 31 47 331 -22 116 33 57 114 38 56 116 54 55 114 18 28 0.70
116 0 45 -22 0 0 12 51 47 48 330 -23 116 58 24 115 3 41 117 19 18 114 43 16 0.71
116 25 55 -21 0 0 12 52 3 48 328 -24 117 23 28 115 28 58 117 44 20 115 8 37 0.71
116 51 42 -20 0 0 12 52 19 49 327 -25 117 49 10 115 54 51 118 10 0 115 34 31 0.71
117 18 7 -19 0 0 12 52 36 50 326 -26 118 15 32 116 21 19 118 36 21 116 1 0 0.71
117 45 11 -18 0 0 12 52 53 50 325 -27 118 42 35 116 48 24 119 3 24 116 28 6 0.71
118 12 55 -17 0 0 12 53 10 51 323 -28 119 10 20 117 16 8 119 31 11 116 55 50 0.71
118 41 22 -16 0 0 12 53 27 51 322 -29 119 38 51 117 44 32 119 59 42 117 24 13 0.72
119 10 32 -15 0 0 12 53 45 51 320 -30 120 8 7 118 13 37 120 29 1 117 53 17 0.72
119 40 28 -14 0 0 12 54 3 52 319 -31 120 38 11 118 43 27 120 59 9 118 23 4 0.72
120 11 13 -13 0 0 12 54 21 52 317 -32 121 9 6 119 14 2 121 30 7 118 53 37 0.72
120 42 47 -12 0 0 12 54 39 53 316 -33 121 40 53 119 45 25 122 2 0 119 24 56 0.72
121 15 14 -11 0 0 12 54 58 53 314 -34 122 13 36 120 17 38 122 34 48 119 57 4 0.73
121 48 36 -10 0 0 12 55 16 53 313 -35 122 47 16 120 50 43 123 8 35 120 30 4 0.73
Uncertainty in time = +/- 6 secs
Prediction of 2017 Oct 12.0
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