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Updated: 2010 OCT 29, 10:37 UT
Event Rank : 77
(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 2010 Dec 18 UT, the 39 km diameter asteroid (302) Clarissa will occult a 10.9 mag star in the constellation Gemini for observers along a fairly narrow path across Australia from Mt Gambier (in morning twilight) past Port Lincon.in South Australia across Western Australia to Exmouth
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.1 mag to 13.9 mag (the magnitude of the asteroid) for at most 5.7 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
147 51 26 -43 0 0 18 24 22 14 329 -1 148 21 36 147 21 10 149 4 51 146 37 23
146 27 51 -42 0 0 18 24 30 15 330 -2 146 57 51 145 57 44 147 40 52 145 14 9
145 3 44 -41 0 0 18 24 39 16 331 -4 145 33 37 144 33 44 146 16 28 143 50 18
143 38 58 -40 0 0 18 24 49 18 332 -5 144 8 46 143 9 2 144 51 29 142 25 42
142 13 23 -39 0 0 18 25 0 19 333 -7 142 43 9 141 43 29 143 25 48 141 0 12
140 46 53 -38 0 0 18 25 12 20 335 -8 141 16 39 140 16 58 141 59 16 139 33 39
139 19 17 -37 0 0 18 25 25 22 336 -10 139 49 5 138 49 20 140 31 45 138 5 56
137 50 27 -36 0 0 18 25 39 23 337 -11 138 20 20 137 20 24 139 3 6 136 36 52
136 20 12 -35 0 0 18 25 54 25 338 -13 136 50 13 135 50 2 137 33 9 135 6 16
134 48 23 -34 0 0 18 26 10 26 339 -14 135 18 34 134 18 1 136 1 44 133 33 58
133 14 47 -33 0 0 18 26 26 27 340 -16 133 45 11 132 44 10 134 28 40 131 59 46
131 39 11 -32 0 0 18 26 45 29 342 -17 132 9 53 131 8 17 132 53 44 130 23 25
130 1 22 -31 0 0 18 27 4 30 343 -19 130 32 24 129 30 6 131 16 44 128 44 41
128 21 3 -30 0 0 18 27 24 31 344 -21 128 52 30 127 49 22 129 37 24 127 3 18
126 37 57 -29 0 0 18 27 46 33 346 -22 127 9 54 126 5 45 127 55 28 125 18 54
124 51 43 -28 0 0 18 28 10 34 347 -24 125 24 15 124 18 55 126 10 37 123 31 9
123 1 57 -27 0 0 18 28 34 35 349 -26 123 35 10 122 28 25 124 22 29 121 39 34
121 8 11 -26 0 0 18 29 1 37 351 -28 121 42 13 120 33 48 122 30 38 119 43 40
119 9 50 -25 0 0 18 29 29 38 353 -30 119 44 49 118 34 27 120 34 33 117 42 47
117 6 13 -24 0 0 18 29 59 39 355 -32 117 42 21 116 29 38 118 33 38 115 36 8
Latitude Latitude Latitude Latitude
116 0 0 -23 29 0 18 30 15 40 356 -33 -23 11 55 -23 46 10 -22 47 30 -24 11 5
115 0 0 -23 1 35 18 30 30 40 357 -33 -22 44 37 -23 18 40 -22 20 21 -23 43 25
114 0 0 -22 34 51 18 30 45 41 358 -34 -22 17 58 -22 51 49 -21 53 50 -23 16 26
113 0 0 -22 8 46 18 31 0 41 359 -35 -21 51 59 -22 25 38 -21 27 59 -22 50 6
112 0 0 -21 43 21 18 31 15 41 0 -36 -21 26 39 -22 0 7 -21 2 47 -22 24 27
111 0 0 -21 18 35 18 31 30 42 2 -37 -21 1 59 -21 35 17 -20 38 15 -21 59 29
Uncertainty in time = +/- 5 secs
Prediction of 2010 Nov 19.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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