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Updated: 2018 Apr 27, 22:53 UT
Event Rank : 68
(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 Jun 03 UT, the 71 km diameter asteroid (1241) Dysona will occult a 12.4 mag star in the constellation Ara for observers along a somewhat uncertain path across eastern Victoria, central New South Wales and which fades into evening twilight over south-western Queensland.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.74 mag to 13.94 mag (the magnitude of the asteroid) for at most 6.3 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 2UCAC 07869390 by 1241 Dysona on 2018 Jun 3
Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2 Alt
E. Longitude Latitude U.T. Alt Az Alt Crn
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
151 37 6 -44 42 48 8 15 5 37 134 -19 151 1 56 -44 38 3 152 12 5 -44 47 13 150 8 58 -44 30 14 153 4 15 -44 53 11 0.61
151 11 22 -43 47 8 8 15 11 36 135 -19 150 36 31 -43 42 3 151 46 3 -43 51 51 149 44 1 -43 33 45 152 37 43 -43 58 16 0.61
150 45 3 -42 50 23 8 15 18 35 136 -18 150 10 30 -42 44 58 151 19 27 -42 55 26 149 18 24 -42 36 8 152 10 41 -43 2 20 0.61
150 18 7 -41 52 29 8 15 25 34 136 -18 149 43 49 -41 46 42 150 52 15 -41 57 54 148 52 5 -41 37 19 151 43 6 -42 5 19 0.61
149 50 28 -40 53 20 8 15 32 34 137 -17 149 16 24 -40 47 9 150 24 23 -40 59 8 148 24 59 -40 37 9 151 14 53 -41 7 6 0.61
149 22 4 -39 52 49 8 15 39 33 137 -17 148 48 10 -39 46 12 149 55 47 -39 59 1 147 57 1 -39 35 30 150 45 58 -40 7 36 0.61
148 52 47 -38 50 46 8 15 45 32 138 -16 148 19 2 -38 43 41 149 26 21 -38 57 26 147 28 6 -38 32 15 150 16 17 -39 6 40 0.61
148 22 33 -37 47 3 8 15 52 30 139 -16 147 48 54 -37 39 27 148 55 59 -37 54 13 146 58 6 -37 27 11 149 45 44 -38 4 11 0.61
147 51 13 -36 41 28 8 15 59 29 139 -15 147 17 38 -36 33 17 148 24 35 -36 49 12 146 26 54 -36 20 7 149 14 13 -36 59 57 0.61
147 18 40 -35 33 49 8 16 6 28 140 -14 146 45 5 -35 24 58 147 52 1 -35 42 10 145 54 19 -35 10 46 148 41 35 -35 53 48 0.61
146 44 43 -34 23 47 8 16 13 27 140 -13 146 11 5 -34 14 12 147 18 7 -34 32 50 145 20 11 -33 58 50 148 7 42 -34 45 28 0.61
146 9 9 -33 11 4 8 16 19 26 141 -12 145 35 23 -33 0 39 146 42 40 -33 20 56 144 44 13 -32 43 55 147 32 23 -33 34 42 0.61
145 31 43 -31 55 15 8 16 26 25 141 -12 144 57 42 -31 43 51 146 5 25 -32 6 2 144 6 7 -31 25 32 146 55 23 -32 21 6 0.62
144 52 3 -30 35 47 8 16 33 23 142 -11 144 17 41 -30 23 13 145 26 4 -30 47 40 143 25 29 -30 3 1 146 16 26 -31 4 15 0.62
144 9 43 -29 11 59 8 16 40 22 142 -10 143 34 50 -28 58 1 144 44 11 -29 25 10 142 41 44 -28 35 31 145 35 9 -29 43 33 0.62
143 24 5 -27 42 53 8 16 47 20 143 -9 142 48 28 -27 27 11 143 59 13 -27 57 40 141 54 5 -27 1 48 144 51 2 -28 18 16 0.62
142 34 17 -26 7 8 8 16 53 19 143 -7 141 57 36 -25 49 12 143 10 22 -26 23 58 141 1 21 -25 20 2 144 3 24 -26 47 18 0.63
141 38 59 -24 22 41 8 17 0 17 144 -6 141 0 43 -24 1 44 142 16 27 -24 42 14 140 1 38 -23 27 19 143 11 17 -25 9 11 0.63
Uncertainty in time = +/- 5 secs
Prediction of 2018 Apr 27.0
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