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Updated: 2009 JUL 16, 01:58 UT
Event Rank : 64
(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 2009 Aug 23 UT, the 134 km diameter asteroid (247) Eukrate will occult a 12.6 mag star in the constellation Ara for observers along a path across beginning near Mt Gambier, moving north and passing near Mildura and Broken Hill. In Queensland passing near Longreach, Townsville and Cairns.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.4 mag to 13.6 mag (the magnitude of the asteroid) for at most 10.7 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC.
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
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
148 45 47 -10 0 0 9 56 36 46 192 -28 149 23 31 148 8 1 150 35 8 146 56 10
148 31 1 -11 0 0 9 56 29 47 192 -28 149 8 53 147 53 7 150 20 46 146 41 0
148 16 6 -12 0 0 9 56 22 48 192 -28 148 54 7 147 38 3 150 6 16 146 25 38
148 1 1 -13 0 0 9 56 16 49 192 -28 148 39 12 147 22 48 149 51 39 146 10 4
147 45 46 -14 0 0 9 56 9 50 192 -28 148 24 7 147 7 22 149 36 54 145 54 17
147 30 19 -15 0 0 9 56 1 51 192 -28 148 8 52 146 51 43 149 22 0 145 38 16
147 14 39 -16 0 0 9 55 54 52 192 -27 147 53 24 146 35 51 149 6 56 145 21 59
146 58 46 -17 0 0 9 55 47 53 192 -27 147 37 44 146 19 44 148 51 41 145 5 26
146 42 38 -18 0 0 9 55 39 55 192 -27 147 21 51 146 3 22 148 36 14 144 48 37
146 26 15 -19 0 0 9 55 32 56 192 -27 147 5 43 145 46 44 148 20 34 144 31 28
146 9 36 -20 0 0 9 55 24 57 192 -27 146 49 20 145 29 48 148 4 41 144 14 1
145 52 39 -21 0 0 9 55 17 58 192 -26 146 32 40 145 12 34 147 48 34 143 56 12
145 35 23 -22 0 0 9 55 9 59 192 -26 146 15 43 144 54 59 147 32 11 143 38 2
145 17 47 -23 0 0 9 55 1 60 191 -26 145 58 27 144 37 4 147 15 31 143 19 28
144 59 50 -24 0 0 9 54 53 61 191 -25 145 40 50 144 18 46 146 58 33 143 0 30
144 41 30 -25 0 0 9 54 45 62 191 -25 145 22 52 144 0 4 146 41 16 142 41 5
144 22 47 -26 0 0 9 54 36 63 191 -25 145 4 31 143 40 57 146 23 38 142 21 12
144 3 37 -27 0 0 9 54 28 64 191 -25 144 45 46 143 21 22 146 5 39 142 0 50
143 44 0 -28 0 0 9 54 20 65 191 -24 144 26 35 143 1 19 145 47 16 141 39 56
143 23 54 -29 0 0 9 54 11 66 191 -24 144 6 57 142 40 46 145 28 28 141 18 29
143 3 17 -30 0 0 9 54 3 67 191 -24 143 46 49 142 19 40 145 9 14 140 56 26
142 42 8 -31 0 0 9 53 54 68 191 -23 143 26 9 141 57 59 144 49 32 140 33 46
142 20 23 -32 0 0 9 53 45 69 191 -23 143 4 57 141 35 42 144 29 19 140 10 26
141 58 1 -33 0 0 9 53 37 70 190 -23 142 43 9 141 12 45 144 8 34 139 46 22
141 34 59 -34 0 0 9 53 28 71 190 -22 142 20 43 140 49 7 143 47 15 139 21 34
141 11 15 -35 0 0 9 53 19 72 190 -22 141 57 36 140 24 45 143 25 19 138 55 57
140 46 45 -36 0 0 9 53 10 73 190 -21 141 33 47 139 59 35 143 2 44 138 29 28
140 21 28 -37 0 0 9 53 1 74 189 -21 141 9 11 139 33 34 142 39 27 138 2 4
139 55 19 -38 0 0 9 52 52 75 189 -21 140 43 47 139 6 40 142 15 26 137 33 41
139 28 14 -39 0 0 9 52 43 76 188 -20 140 17 30 138 38 47 141 50 37 137 4 15
139 0 11 -40 0 0 9 52 33 77 187 -20 139 50 17 138 9 53 141 24 56 136 33 42
138 31 5 -41 0 0 9 52 24 78 186 -19 139 22 3 137 39 53 140 58 21 136 1 57
138 0 50 -42 0 0 9 52 15 79 185 -19 138 52 45 137 8 41 140 30 47 135 28 54
Latitude Latitude Latitude Latitude
137 0 0 -43 53 56 9 51 57 81 182 -18 -45 30 50 -42 16 18 -48 33 12 -39 8 30
136 0 0 -45 38 3 9 51 40 82 176 -17 -47 11 18 -44 4 8 -50 6 54 -41 3 36
Uncertainty in time = +/- 10 secs
Prediction of 2009 Jul 16.0
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