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Updated: 2015 Jun 12, 17:04 UT
Event Rank : 12
(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 2015 Jul 28 UT, the 18 km diameter asteroid (3167) Babcock will occult a 6.4 mag star in the constellation Scorpius for observers along a large uncertainty path running down the eastern coast of Australia, beginning near Fraser Island, running centrally over Brisbane, Sydney and Hobart with Canberra just outside the 1 sigma line.
In the case of an occultation, the combined light of the asteroid and the star will drop by 8.4 mag to 14.8 mag (the magnitude of the asteroid) for at most 3.9 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: .
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 HIP 81198 by 3167 Babcock on 2015 Jul 28
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
155 21 34 -18 0 0 10 9 2 62 187 -39 155 27 4 155 16 4 156 27 18 154 15 42
155 8 30 -19 0 0 10 8 41 63 186 -39 155 14 2 155 2 58 156 14 39 154 2 12
154 55 9 -20 0 0 10 8 20 64 186 -39 155 0 43 154 49 34 156 1 45 153 48 23
154 41 29 -21 0 0 10 7 59 65 186 -39 154 47 6 154 35 52 155 48 35 153 34 14
154 27 30 -22 0 0 10 7 37 66 185 -38 154 33 10 154 21 51 155 35 6 153 19 43
154 13 10 -23 0 0 10 7 15 67 185 -38 154 18 52 154 7 27 155 21 19 153 4 49
153 58 27 -24 0 0 10 6 53 68 185 -38 154 4 12 153 52 42 155 7 11 152 49 31
153 43 20 -25 0 0 10 6 31 69 184 -38 153 49 8 153 37 32 154 52 41 152 33 46
153 27 48 -26 0 0 10 6 8 70 184 -38 153 33 39 153 21 56 154 37 47 152 17 34
153 11 48 -27 0 0 10 5 46 71 183 -37 153 17 43 153 5 53 154 22 29 152 0 52
152 55 19 -28 0 0 10 5 23 72 182 -37 153 1 18 152 49 20 154 6 44 151 43 38
152 38 19 -29 0 0 10 5 0 73 181 -37 152 44 22 152 32 16 153 50 30 151 25 51
152 20 46 -30 0 0 10 4 37 74 181 -36 152 26 52 152 14 39 153 33 45 151 7 28
152 2 37 -31 0 0 10 4 14 75 179 -36 152 8 48 151 56 26 153 16 28 150 48 26
151 43 51 -32 0 0 10 3 50 76 178 -36 151 50 7 151 37 35 152 58 37 150 28 44
151 24 25 -33 0 0 10 3 27 77 177 -36 151 30 45 151 18 4 152 40 8 150 8 19
151 4 16 -34 0 0 10 3 3 78 175 -35 151 10 41 150 57 50 152 21 0 149 47 7
150 43 21 -35 0 0 10 2 39 79 173 -35 150 49 52 150 36 49 152 1 9 149 25 6
150 21 37 -36 0 0 10 2 15 80 170 -34 150 28 14 150 15 0 151 40 34 149 2 13
149 59 1 -37 0 0 10 1 51 81 167 -34 150 5 44 149 52 17 151 19 9 148 38 23
149 35 29 -38 0 0 10 1 27 82 162 -34 149 42 18 149 28 39 150 56 54 148 13 32
149 10 57 -39 0 0 10 1 3 82 157 -33 149 17 53 149 4 0 150 33 43 147 47 37
148 45 21 -40 0 0 10 0 38 83 151 -33 148 52 25 148 38 17 150 9 32 147 20 33
148 18 36 -41 0 0 10 0 14 83 143 -32 148 25 48 148 11 25 149 44 18 146 52 15
147 50 37 -42 0 0 9 59 49 84 133 -32 147 57 57 147 43 18 149 17 55 146 22 36
147 21 19 -43 0 0 9 59 25 84 121 -31 147 28 47 147 13 50 148 50 19 145 51 32
146 50 35 -44 0 0 9 59 0 84 109 -31 146 58 12 146 42 57 148 21 24 145 18 55
145 0 0 -47 13 58 9 57 39 83 77 -29 -47 27 12 -47 0 43 -49 50 24 -44 33 28
Uncertainty in time = +/- 21 secs
Prediction of 2015 Jun 13.0
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