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Updated: 2018 May 15, 17:11 UT
Event Rank : 99
(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 Aug 18 UT, the 134 km diameter asteroid (247) Eukrate will occult a 11.8 mag star in the constellation Norma for observers along a path across Northern Territory and West Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.03 mag to 13.69 mag (the magnitude of the asteroid) for at most 11.0 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 8337-00697-1 by 247 Eukrate on 2018 Aug 18
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
130 43 30 -10 0 0 10 55 18 47 192 -25 131 22 10 130 4 45 131 37 55 129 48 56 -0.09
130 23 49 -11 0 0 10 55 11 48 192 -25 131 2 39 129 44 54 131 18 28 129 29 1 -0.09
130 3 51 -12 0 0 10 55 4 49 192 -25 130 42 52 129 24 45 130 58 45 129 8 48 -0.09
129 43 35 -13 0 0 10 54 56 50 192 -24 130 22 48 129 4 18 130 38 46 128 48 16 -0.09
129 23 1 -14 0 0 10 54 49 51 192 -24 130 2 26 128 43 31 130 18 29 128 27 23 -0.10
129 2 6 -15 0 0 10 54 41 52 192 -24 129 41 45 128 22 23 129 57 53 128 6 9 -0.10
128 40 51 -16 0 0 10 54 33 53 191 -24 129 20 44 128 0 52 129 36 58 127 44 32 -0.10
128 19 12 -17 0 0 10 54 25 54 191 -24 128 59 21 127 38 57 129 15 42 127 22 31 -0.10
127 57 9 -18 0 0 10 54 17 55 191 -23 128 37 35 127 16 37 128 54 2 127 0 4 -0.10
127 34 41 -19 0 0 10 54 9 56 191 -23 128 15 25 126 53 51 128 31 59 126 37 10 -0.10
127 11 45 -20 0 0 10 54 1 57 191 -23 127 52 48 126 30 36 128 9 30 126 13 47 -0.10
126 48 20 -21 0 0 10 53 52 59 191 -22 127 29 44 126 6 50 127 46 34 125 49 53 -0.10
126 24 25 -22 0 0 10 53 44 60 190 -22 127 6 10 125 42 33 127 23 9 125 25 26 -0.10
125 59 57 -23 0 0 10 53 35 61 190 -22 126 42 5 125 17 41 126 59 13 125 0 25 -0.10
125 34 54 -24 0 0 10 53 27 62 190 -21 126 17 26 124 52 14 126 34 45 124 34 47 -0.10
125 9 15 -25 0 0 10 53 18 63 190 -21 125 52 13 124 26 8 126 9 42 124 8 30 -0.10
124 42 56 -26 0 0 10 53 9 64 189 -21 125 26 22 123 59 21 125 44 2 123 41 32 -0.11
124 15 56 -27 0 0 10 53 0 65 189 -20 124 59 51 123 31 51 125 17 42 123 13 50 -0.11
123 48 12 -28 0 0 10 52 51 66 189 -20 124 32 37 123 3 36 124 50 41 122 45 21 -0.11
123 19 41 -29 0 0 10 52 41 67 188 -20 124 4 39 122 34 31 124 22 56 122 16 3 -0.11
122 50 20 -30 0 0 10 52 32 68 188 -19 123 35 53 122 4 35 123 54 24 121 45 52 -0.11
122 20 5 -31 0 0 10 52 22 69 187 -19 123 6 15 121 33 43 123 25 1 121 14 44 -0.11
121 0 0 -33 30 25 10 51 58 72 185 -18 -34 56 36 -32 3 28 -35 31 32 -31 27 47 -0.11
120 0 0 -35 15 26 10 51 41 73 183 -17 -36 38 55 -33 51 15 -37 12 46 -33 16 42 -0.11
119 0 0 -36 54 20 10 51 25 75 181 -16 -38 15 15 -35 32 46 -38 48 4 -34 59 18 -0.11
118 0 0 -38 27 29 10 51 9 76 178 -16 -39 45 59 -37 8 24 -40 17 49 -36 35 58 -0.12
Uncertainty in time = +/- 4 secs
Prediction of 2018 May 15.0
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