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Updated: 2011 JUL 21, 22:10 UT
Event Rank : 91
(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 2011 Aug 14 UT, the 101 km diameter asteroid (191) Kolga will occult a 12.8 mag star in the constellation Pisces for observers along a north-to-south path passing near east coast of NSW and Tasmania.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.0 mag to 13.2 mag (the magnitude of the asteroid) for at most 13.2 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 Limit1 Path Limit2 Error Limit1 Error Limit2
E. Longitude Latitude U.T. Alt Az Alt
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
159 52 12 -22 2 5 18 32 18 42 287 -17 160 32 31 -22 17 31 159 12 33 -21 46 39 161 13 33 -22 32 56 158 33 33 -21 31 12
159 17 36 -22 55 27 18 32 33 43 288 -18 159 58 3 -23 10 59 158 37 50 -22 39 54 160 39 12 -23 26 30 157 58 43 -22 24 21
158 43 48 -23 49 3 18 32 47 43 289 -19 159 24 23 -24 4 42 158 3 53 -23 33 24 160 5 41 -24 20 20 157 24 37 -23 17 45
158 10 45 -24 42 57 18 33 2 43 290 -19 158 51 31 -24 58 42 157 30 40 -24 27 11 159 33 0 -25 14 28 156 51 14 -24 11 25
157 38 27 -25 37 8 18 33 16 43 291 -20 158 19 25 -25 53 1 156 58 9 -25 21 15 159 1 8 -26 8 53 156 18 32 -25 5 22
157 6 52 -26 31 38 18 33 31 43 293 -20 157 48 5 -26 47 39 156 26 21 -26 15 38 158 30 2 -27 3 38 155 46 30 -25 59 38
156 36 1 -27 26 29 18 33 45 43 294 -21 157 17 30 -27 42 37 155 55 14 -27 10 21 157 59 44 -27 58 45 155 15 8 -26 54 13
156 5 51 -28 21 41 18 34 0 43 295 -21 156 47 39 -28 37 57 155 24 48 -28 5 26 157 30 11 -28 54 13 154 44 25 -27 49 10
155 36 24 -29 17 17 18 34 14 43 296 -22 156 18 31 -29 33 41 154 55 1 -29 0 52 157 1 25 -29 50 6 154 14 20 -28 44 28
155 7 38 -30 13 17 18 34 29 43 297 -22 155 50 7 -30 29 50 154 25 54 -29 56 44 156 33 24 -30 46 24 153 44 53 -29 40 11
154 39 34 -31 9 43 18 34 43 43 298 -22 155 22 28 -31 26 26 153 57 27 -30 53 0 156 6 9 -31 43 9 153 16 3 -30 36 18
154 12 12 -32 6 37 18 34 58 43 299 -23 154 55 32 -32 23 29 153 29 39 -31 49 45 155 39 41 -32 40 23 152 47 51 -31 32 53
153 45 31 -33 4 0 18 35 12 42 301 -23 154 29 20 -33 21 3 153 2 31 -32 46 58 155 14 0 -33 38 7 152 20 16 -32 29 56
153 19 33 -34 1 55 18 35 27 42 302 -24 154 3 54 -34 19 9 152 36 2 -33 44 42 154 49 6 -34 36 24 151 53 19 -33 27 29
152 54 18 -35 0 23 18 35 42 42 303 -24 153 39 13 -35 17 48 152 10 15 -34 42 59 154 25 2 -35 35 15 151 27 1 -34 25 35
152 29 48 -35 59 27 18 35 56 42 304 -24 153 15 20 -36 17 4 151 45 9 -35 41 50 154 1 49 -36 34 43 151 1 21 -35 24 15
152 6 4 -36 59 8 18 36 11 41 305 -24 152 52 17 -37 16 58 151 20 46 -36 41 19 153 39 28 -37 34 50 150 36 21 -36 23 31
151 43 7 -37 59 29 18 36 25 41 306 -25 152 30 4 -38 17 33 150 57 7 -37 41 27 153 18 2 -38 35 39 150 12 1 -37 23 26
151 20 59 -39 0 34 18 36 40 40 307 -25 152 8 45 -39 18 52 150 34 14 -38 42 17 152 57 33 -39 37 12 149 48 25 -38 24 3
150 59 44 -40 2 24 18 36 54 40 308 -25 151 48 22 -40 20 57 150 12 9 -39 43 52 152 38 6 -40 39 32 149 25 32 -39 25 23
150 39 24 -41 5 3 18 37 9 40 309 -25 151 28 59 -41 23 52 149 50 54 -40 46 15 152 19 43 -41 42 43 149 3 27 -40 27 30
150 20 3 -42 8 33 18 37 23 39 310 -25 151 10 41 -42 27 40 149 30 34 -41 49 29 152 2 31 -42 46 49 148 42 10 -41 30 27
150 1 45 -43 13 0 18 37 38 38 311 -25 150 53 31 -43 32 25 149 11 11 -42 53 38 151 46 35 -43 51 52 148 21 47 -42 34 19
149 44 36 -44 18 27 18 37 52 38 312 -26 150 37 37 -44 38 11 148 52 51 -43 58 45 151 32 1 -44 57 58 148 2 19 -43 39 7
149 28 41 -45 24 58 18 38 7 37 312 -26 150 23 6 -45 45 3 148 35 39 -45 4 56 151 18 58 -46 5 11 147 43 53 -44 44 57
149 14 10 -46 32 38 18 38 21 37 313 -26 150 10 6 -46 53 5 148 19 41 -46 12 14 151 7 36 -47 13 36 147 26 35 -45 51 54
149 1 10 -47 41 33 18 38 36 36 314 -26 149 58 48 -48 2 24 148 5 6 -47 20 45 150 58 7 -48 23 19 147 10 30 -47 0 2
148 49 53 -48 51 49 18 38 50 35 315 -26 149 49 25 -49 13 6 147 52 3 -48 30 36 150 50 45 -49 34 27 146 55 48 -48 9 27
148 40 32 -50 3 32 18 39 5 34 315 -25 149 42 12 -50 25 18 147 40 44 -49 41 52 150 45 50 -50 47 8 146 42 38 -49 20 16
148 33 25 -51 16 52 18 39 19 33 316 -25 149 37 28 -51 39 7 147 31 23 -50 54 41 150 43 41 -52 1 28 146 31 14 -50 32 36
Uncertainty in time = +/- 8 secs
Prediction of 2011 Jul 22.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
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[Asteroid Occultation Results]
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