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Updated: 2018 May 15, 17:50 UT
Event Rank : 94
(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 Dec 15 UT, the 50 km diameter asteroid (186) Celuta will occult a 12.4 mag star in the constellation Leo for observers along a path across West Australia and Northern Territory, passing over Cervantes and Katherine.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.58 mag to 13.68 mag (the magnitude of the asteroid) for at most 10.3 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 1973-00736-1 by 186 Celuta on 2018 Dec 15
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
112 8 23 -33 0 0 18 6 36 15 45 -29 112 32 28 111 44 14 112 50 24 111 26 10 0.16
113 24 49 -32 0 0 18 6 46 16 44 -29 113 48 26 113 1 9 114 6 2 112 43 26 0.16
114 39 17 -31 0 0 18 6 56 18 43 -30 115 2 28 114 16 3 115 19 45 113 58 39 0.16
115 51 55 -30 0 0 18 7 7 19 43 -30 116 14 42 115 29 5 116 31 41 115 12 0 0.16
117 2 53 -29 0 0 18 7 19 21 42 -30 117 25 18 116 40 26 117 42 1 116 23 38 0.16
118 12 19 -28 0 0 18 7 31 22 41 -31 118 34 24 117 50 13 118 50 51 117 33 40 0.17
119 20 20 -27 0 0 18 7 45 24 41 -31 119 42 6 118 58 33 119 58 20 118 42 15 0.17
120 27 4 -26 0 0 18 7 59 25 40 -31 120 48 32 120 5 34 121 4 32 119 49 30 0.17
121 32 35 -25 0 0 18 8 13 27 40 -31 121 53 47 121 11 22 122 9 36 120 55 30 0.17
122 37 2 -24 0 0 18 8 29 28 39 -31 122 57 58 122 16 3 123 13 36 122 0 23 0.17
123 40 28 -23 0 0 18 8 45 29 38 -31 124 1 11 123 19 44 124 16 38 123 4 14 0.17
124 43 0 -22 0 0 18 9 2 31 38 -32 125 3 30 124 22 28 125 18 48 124 7 8 0.17
125 44 42 -21 0 0 18 9 20 32 37 -32 126 5 0 125 24 22 126 20 10 125 9 11 0.17
126 45 39 -20 0 0 18 9 38 34 37 -32 127 5 47 126 25 30 127 20 49 126 10 27 0.17
127 45 56 -19 0 0 18 9 57 35 36 -32 128 5 55 127 25 57 128 20 49 127 11 2 0.17
128 45 38 -18 0 0 18 10 16 37 36 -32 129 5 28 128 25 48 129 20 16 128 10 59 0.17
129 44 48 -17 0 0 18 10 37 38 35 -31 130 4 30 129 25 6 130 19 12 129 10 23 0.17
130 43 30 -16 0 0 18 10 58 39 35 -31 131 3 5 130 23 55 131 17 42 130 9 17 0.18
131 41 49 -15 0 0 18 11 19 41 34 -31 132 1 18 131 22 20 132 15 50 131 7 47 0.18
132 39 48 -14 0 0 18 11 42 42 34 -31 132 59 12 132 20 25 133 13 41 132 5 56 0.18
133 37 32 -13 0 0 18 12 4 44 33 -31 133 56 51 133 18 13 134 11 17 133 3 48 0.18
134 35 3 -12 0 0 18 12 28 45 33 -31 134 54 19 134 15 48 135 8 42 134 1 26 0.18
135 32 27 -11 0 0 18 12 52 46 32 -30 135 51 39 135 13 15 136 6 0 134 58 55 0.18
136 29 46 -10 0 0 18 13 17 48 32 -30 136 48 56 136 10 36 137 3 16 135 56 17 0.18
Uncertainty in time = +/- 5 secs
Prediction of 2018 May 15.0
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