|
|
Updated: 2018 APR 27, 22:49 UT
Event Rank : 54
(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 May 19 UT, the 31.1 km diameter asteroid (852) Wladilena will occult a 9.5 mag star in the constellation Ara for observers along a narrow path across Australia, from Bridgetown in south-western Western Australia across central and north-eastern Northern Territory to near Gove.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.98 mag to 12.41 mag (the magnitude of the asteroid) for at most 2.6 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, astrometry for the asteroid kindly provided by 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.
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
140 0 6 - 3 0 0 14 53 6 36 166 -73 139 48 56 140 11 15 139 21 37 140 38 15 -0.75
139 38 45 - 4 0 0 14 53 13 37 166 -74 139 27 31 139 49 58 139 0 3 140 17 7 -0.75
139 16 25 - 5 0 0 14 53 20 38 165 -75 139 5 6 139 27 41 138 37 28 139 55 1 -0.75
138 53 3 - 6 0 0 14 53 27 39 165 -76 138 41 40 139 4 25 138 13 50 139 31 55 -0.75
138 28 39 - 7 0 0 14 53 35 39 164 -77 138 17 11 138 40 5 137 49 8 139 7 48 -0.75
138 3 9 - 8 0 0 14 53 43 40 164 -78 137 51 35 138 14 41 137 23 19 138 42 36 -0.75
137 36 31 - 9 0 0 14 53 51 41 163 -79 137 24 52 137 48 9 136 56 20 138 16 19 -0.75
137 8 44 -10 0 0 14 53 59 42 163 -80 136 56 57 137 20 28 136 28 9 137 48 54 -0.74
136 39 42 -11 0 0 14 54 7 43 162 -81 136 27 49 136 51 34 135 58 43 137 20 16 -0.74
136 9 25 -12 0 0 14 54 16 44 161 -82 135 57 23 136 21 24 135 27 59 136 50 25 -0.74
Latitude Latitude Latitude Latitude
135 0 0 -14 8 27 14 54 35 45 160 -84 -13 46 35 -14 30 7 -12 52 25 -15 22 0 -0.74
134 0 0 -15 50 37 14 54 51 46 159 -86 -15 29 50 -16 11 12 -14 38 30 -17 0 36 -0.74
133 0 0 -17 25 38 14 55 6 48 158 -86 -17 5 48 -17 45 18 -16 16 53 -18 32 32 -0.74
132 0 0 -18 54 20 14 55 21 49 156 -86 -18 35 20 -19 13 11 -17 48 31 -19 58 31 -0.74
131 0 0 -20 17 23 14 55 35 49 155 -86 -19 59 7 -20 35 31 -19 14 8 -21 19 11 -0.74
130 0 0 -21 35 20 14 55 48 50 154 -85 -21 17 43 -21 52 50 -20 34 23 -22 35 0 -0.74
129 0 0 -22 48 39 14 56 2 51 152 -83 -22 31 37 -23 5 35 -21 49 45 -23 46 24 -0.74
128 0 0 -23 57 45 14 56 15 52 151 -82 -23 41 15 -24 14 10 -23 0 41 -24 53 45 -0.73
127 0 0 -25 2 57 14 56 27 52 150 -81 -24 46 55 -25 18 54 -24 7 34 -25 57 23 -0.73
126 0 0 -26 4 34 14 56 39 52 149 -80 -25 48 58 -26 20 5 -25 10 42 -26 57 33 -0.73
125 0 0 -27 2 51 14 56 51 53 148 -78 -26 47 40 -27 17 59 -26 10 22 -27 54 31 -0.73
124 0 0 -27 58 3 14 57 2 53 146 -77 -27 43 13 -28 12 49 -27 6 50 -28 48 29 -0.73
123 0 0 -28 50 21 14 57 13 53 145 -76 -28 35 51 -29 4 47 -28 0 18 -29 39 40 -0.73
122 0 0 -29 39 56 14 57 24 54 144 -75 -29 25 45 -29 54 4 -28 50 59 -30 28 13 -0.73
121 0 0 -30 26 58 14 57 35 54 143 -74 -30 13 5 -30 40 49 -29 39 1 -31 14 18 -0.73
120 0 0 -31 11 37 14 57 45 54 142 -73 -30 57 59 -31 25 12 -30 24 36 -31 58 3 -0.73
119 0 0 -31 54 0 14 57 55 54 141 -71 -31 40 37 -32 7 20 -31 7 51 -32 39 35 -0.73
118 0 0 -32 34 15 14 58 4 54 140 -70 -32 21 6 -32 47 21 -31 48 54 -33 19 3 -0.73
117 0 0 -33 12 27 14 58 14 54 139 -69 -32 59 31 -33 25 21 -32 27 52 -33 56 32 -0.73
116 0 0 -33 48 44 14 58 23 54 138 -68 -33 36 0 -34 1 25 -33 4 51 -34 32 8 -0.73
115 0 0 -34 23 11 14 58 32 54 138 -67 -34 10 38 -34 35 41 -33 39 57 -35 5 57 -0.73
114 0 0 -34 55 52 14 58 41 53 137 -66 -34 43 30 -35 8 12 -34 13 15 -35 38 2 -0.73
113 0 0 -35 26 53 14 58 50 53 136 -65 -35 14 41 -35 39 3 -34 44 50 -36 8 30 -0.73
112 0 0 -35 56 18 14 58 58 53 135 -65 -35 44 15 -36 8 18 -35 14 47 -36 37 23 -0.73
111 0 0 -36 24 10 14 59 7 53 135 -64 -36 12 16 -36 36 2 -35 43 10 -37 4 46 -0.73
110 0 0 -36 50 34 14 59 15 53 134 -63 -36 38 48 -37 2 18 -36 10 2 -37 30 43 -0.73
109 0 0 -37 15 32 14 59 23 52 134 -62 -37 3 54 -37 27 9 -36 35 27 -37 55 15 -0.73
Uncertainty in time = +/- 3 secs
Prediction of 2018 Apr 27.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
[Top of Page][Return to Home Page]