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Updated: 2012 NOV 29, 22:46 UT
Event Rank : 68
(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 2012 Dec 06 UT, the 45 km diameter asteroid (182) Elsa will occult a 10.7 mag star in the constellation Cancer for observers along a path across north-eastern Australia, from Hervey Bay roughly following the Queensland caost to Ingham and then inland to south of Weipa. Brisbane is on the edge of the one sigma limit.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.7 mag to 12.2 mag (the magnitude of the asteroid) for at most 43.9 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: 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
157 10 17 -31 0 0 16 25 16 40 7 -21 157 32 24 156 48 8 158 10 20 156 9 55
156 21 25 -30 0 0 16 26 42 41 7 -22 156 43 25 155 59 22 157 21 11 155 21 20
155 31 47 -29 0 0 16 28 10 41 8 -23 155 53 42 155 9 50 156 31 18 154 31 58
154 41 24 -28 0 0 16 29 40 42 9 -24 155 3 14 154 19 32 155 40 41 153 41 49
153 50 15 -27 0 0 16 31 12 43 10 -25 154 12 0 153 28 27 154 49 20 152 50 51
152 58 19 -26 0 0 16 32 46 44 10 -26 153 20 0 152 36 35 153 57 12 151 59 6
152 5 35 -25 0 0 16 34 22 45 11 -27 152 27 13 151 43 54 153 4 19 151 6 31
151 12 2 -24 0 0 16 35 59 46 12 -28 151 33 37 150 50 24 152 10 39 150 13 6
150 17 40 -23 0 0 16 37 39 47 13 -29 150 39 13 149 56 5 151 16 10 149 18 51
149 22 28 -22 0 0 16 39 19 48 14 -30 149 43 59 149 0 55 150 20 53 148 23 43
148 26 26 -21 0 0 16 41 2 49 15 -31 148 47 55 148 4 53 149 24 47 147 27 44
147 29 31 -20 0 0 16 42 47 49 16 -32 147 51 0 147 7 59 148 27 50 146 30 51
146 31 44 -19 0 0 16 44 33 50 17 -33 146 53 12 146 10 12 147 30 2 145 33 4
145 33 2 -18 0 0 16 46 21 51 18 -34 145 54 31 145 11 31 146 31 21 144 34 22
144 33 26 -17 0 0 16 48 10 52 19 -35 144 54 56 144 11 54 145 31 47 143 34 44
143 32 54 -16 0 0 16 50 1 53 20 -36 143 54 25 143 11 20 144 31 18 142 34 8
142 31 25 -15 0 0 16 51 54 53 22 -37 142 52 57 142 9 49 143 29 54 141 32 33
141 28 57 -14 0 0 16 53 48 54 23 -39 141 50 32 141 7 19 142 27 32 140 29 58
140 25 29 -13 0 0 16 55 44 55 24 -40 140 47 7 140 3 48 141 24 12 139 26 22
139 21 0 -12 0 0 16 57 42 55 26 -41 139 42 41 138 59 15 140 19 53 138 21 43
138 15 27 -11 0 0 16 59 41 56 27 -42 138 37 13 137 53 38 139 14 31 137 15 59
137 8 50 -10 0 0 17 1 41 57 29 -43 137 30 41 136 46 56 138 8 7 136 9 8
136 1 7 - 9 0 0 17 3 43 57 31 -44 136 23 3 135 39 7 137 0 38 135 1 9
134 52 15 - 8 0 0 17 5 47 58 32 -45 135 14 17 134 30 9 135 52 2 133 52 0
133 42 12 - 7 0 0 17 7 52 58 34 -46 134 4 20 133 19 59 134 42 17 132 41 38
132 30 56 - 6 0 0 17 9 58 59 36 -48 132 53 12 132 8 35 133 31 21 131 30 1
131 18 24 - 5 0 0 17 12 6 59 38 -49 131 40 48 130 55 55 132 19 12 130 17 6
Uncertainty in time = +/- 49 secs
Prediction of 2012 Dec 3.0
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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