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Updated: 2018 Jun 23, 00:51 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 19 UT, the 87 km diameter asteroid (593) Titania will occult a 11.8 mag star in the constellation Scorpius for observers along a path across New Zealand.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.23 mag to 14.95 mag (the magnitude of the asteroid) for at most 106.3 seconds.Note gibbous moon nearby.
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 UCAC4-288-134513 by 593 Titania on 2018 Aug 19
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
179 21 15 -40 33 52 9 6 30 73 292 -42 179 38 12 -40 54 12 179 4 32 -40 13 31 179 46 42 -41 4 17 178 56 19 -40 3 25 0.21
178 3 51 -40 56 26 9 8 11 74 295 -41 178 20 37 -41 16 53 177 47 18 -40 35 58 178 29 3 -41 27 2 177 39 10 -40 25 48 0.21
176 46 6 -41 18 41 9 9 52 74 298 -40 177 2 42 -41 39 15 176 29 44 -40 58 5 177 11 2 -41 49 27 176 21 42 -40 47 52 0.21
175 28 0 -41 40 35 9 11 34 74 300 -40 175 44 25 -42 1 17 175 11 49 -41 19 53 175 52 39 -42 11 33 175 3 52 -41 9 36 0.22
174 9 32 -42 2 11 9 13 15 75 303 -39 174 25 45 -42 22 59 173 53 33 -41 41 21 174 33 54 -42 33 19 173 45 41 -41 31 0 0.22
172 50 41 -42 23 26 9 14 56 75 307 -38 173 6 42 -42 44 22 172 34 54 -42 2 29 173 14 44 -42 54 45 172 27 8 -41 52 5 0.22
171 31 26 -42 44 22 9 16 37 75 310 -37 171 47 15 -43 5 25 171 15 51 -42 23 18 171 55 11 -43 15 52 171 8 12 -42 12 50 0.22
170 11 47 -43 4 57 9 18 19 76 313 -37 170 27 22 -43 26 8 169 56 25 -42 43 46 170 35 11 -43 36 38 169 48 52 -42 33 15 0.23
168 51 42 -43 25 13 9 20 0 76 317 -36 169 7 4 -43 46 30 168 36 34 -43 3 55 169 14 46 -43 57 4 168 29 8 -42 53 20 0.23
167 31 12 -43 45 8 9 21 41 76 320 -35 167 46 19 -44 6 32 167 16 18 -43 23 43 167 53 54 -44 17 10 167 8 59 -43 13 5 0.23
166 10 15 -44 4 42 9 23 23 76 324 -34 166 25 7 -44 26 14 165 55 35 -43 43 11 166 32 35 -44 36 56 165 48 23 -43 32 29 0.24
Uncertainty in time = +/- 40 secs
Prediction of 2018 Jun 23.0
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