|
|
Updated: 2018 APR 27, 22:47 UT
Event Rank : 95
(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 12 UT, the 134 km diameter asteroid (247) Eukrate will occult a 12.1 mag star in the constellation Ara for observers along a broad path of moderate uncertainty across eastern Australia including much of Tasmania, eastern Victoria east of Sale, eastern New South Wales inland form the coast, directly over Canberra to Inverell, and south-eastern Queensland from Warwick to Bundaberg. Brisbane is on the edge, and Sydney just east of the one sigma limit.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.60 mag to 13.46 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.
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
154 39 16 -19 0 0 19 35 38 38 213 -6 153 57 6 155 21 33 153 26 59 155 51 52 0.31
154 17 56 -20 0 0 19 35 43 39 213 -7 153 35 32 155 0 25 153 5 16 155 30 53 0.31
153 56 43 -21 0 0 19 35 49 40 213 -7 153 14 6 154 39 26 152 43 39 155 10 4 0.31
153 35 38 -22 0 0 19 35 55 41 214 -8 152 52 46 154 18 35 152 22 9 154 49 24 0.31
153 14 39 -23 0 0 19 36 2 42 214 -9 152 31 31 153 57 53 152 0 43 154 28 53 0.31
152 53 47 -24 0 0 19 36 8 43 215 -9 152 10 22 153 37 18 151 39 21 154 8 30 0.31
152 33 0 -25 0 0 19 36 14 44 215 -10 151 49 17 153 16 49 151 18 3 153 48 14 0.31
152 12 19 -26 0 0 19 36 21 45 215 -10 151 28 16 152 56 27 150 56 48 153 28 6 0.31
151 51 42 -27 0 0 19 36 27 46 216 -11 151 7 18 152 36 11 150 35 35 153 8 4 0.32
151 31 9 -28 0 0 19 36 34 47 216 -11 150 46 23 152 16 0 150 14 24 152 48 8 0.32
151 10 39 -29 0 0 19 36 41 48 217 -12 150 25 30 151 55 53 149 53 15 152 28 18 0.32
150 50 12 -30 0 0 19 36 48 48 218 -12 150 4 38 151 35 50 149 32 5 152 8 33 0.32
150 29 47 -31 0 0 19 36 55 49 218 -13 149 43 47 151 15 52 149 10 55 151 48 53 0.32
150 9 23 -32 0 0 19 37 2 50 219 -13 149 22 56 150 55 56 148 49 44 151 29 17 0.32
149 49 1 -33 0 0 19 37 9 51 220 -14 149 2 4 150 36 2 148 28 32 151 9 44 0.32
149 28 39 -34 0 0 19 37 16 52 220 -14 148 41 11 150 16 10 148 7 17 150 50 14 0.32
149 8 16 -35 0 0 19 37 24 53 221 -15 148 20 16 149 56 20 147 45 58 150 30 47 0.32
148 47 52 -36 0 0 19 37 31 54 222 -15 147 59 18 149 36 30 147 24 36 150 11 21 0.32
148 27 26 -37 0 0 19 37 39 55 223 -16 147 38 16 149 16 40 147 3 8 149 51 57 0.32
148 6 58 -38 0 0 19 37 47 56 224 -16 147 17 10 148 56 50 146 41 35 149 32 34 0.32
147 46 27 -39 0 0 19 37 54 57 225 -17 146 55 59 148 36 58 146 19 54 149 13 11 0.32
147 25 51 -40 0 0 19 38 2 58 226 -17 146 34 41 148 17 5 145 58 6 148 53 47 0.33
147 5 10 -41 0 0 19 38 10 58 227 -17 146 13 16 147 57 9 145 36 9 148 34 23 0.33
146 44 24 -42 0 0 19 38 18 59 228 -18 145 51 43 147 37 9 145 14 2 148 14 56 0.33
146 23 31 -43 0 0 19 38 26 60 229 -18 145 30 0 147 17 5 144 51 44 147 55 28 0.33
146 2 30 -44 0 0 19 38 34 61 231 -18 145 8 7 146 56 56 144 29 14 147 35 56 0.33
145 41 20 -45 0 0 19 38 42 62 232 -19 144 46 2 146 36 41 144 6 30 147 16 20 0.33
145 20 0 -46 0 0 19 38 50 62 233 -19 144 23 44 146 16 19 143 43 30 146 56 40 0.33
144 58 29 -47 0 0 19 38 58 63 235 -20 144 1 12 145 55 50 143 20 14 146 36 54 0.33
144 36 46 -48 0 0 19 39 7 64 237 -20 143 38 24 145 35 11 142 56 39 146 17 1 0.33
Uncertainty in time = +/- 4 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]