|
|
Updated: 2009 NOV 14, 20:50 UT
Event Rank : 98
(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 Dec 14 UT, the 123 km diameter asteroid (152) Atala will occult a 12.9 mag star in the constellation Auriga for observers along a path across Western Australia from Onslow to Eucla.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.6 mag to 12.5 mag (the magnitude of the asteroid) for at most 9.7 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, 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
142 14 1 -42 0 0 17 27 2 1 321 -13 143 41 52 140 44 55 ... .. .. 139 39 54
141 7 52 -41 0 0 17 27 2 2 322 -14 142 35 20 139 39 6 ... .. .. 138 34 18
140 0 52 -40 0 0 17 27 3 3 323 -15 141 28 3 138 32 19 ... .. .. 137 27 39
138 52 54 -39 0 0 17 27 4 5 324 -17 140 19 55 137 24 28 141 21 45 136 19 51
137 43 52 -38 0 0 17 27 6 6 324 -18 139 10 49 136 15 27 140 12 35 135 10 48
136 33 42 -37 0 0 17 27 8 7 325 -19 138 0 41 135 5 10 139 2 26 134 0 24
135 22 14 -36 0 0 17 27 10 9 326 -21 136 49 23 133 53 29 137 51 12 132 48 31
134 9 24 -35 0 0 17 27 13 10 327 -22 135 36 48 132 40 18 136 38 46 131 35 0
132 55 1 -34 0 0 17 27 17 11 327 -23 134 22 50 131 25 26 135 25 2 130 19 44
131 38 59 -33 0 0 17 27 21 13 328 -25 133 7 19 130 8 45 134 9 50 129 2 32
130 21 6 -32 0 0 17 27 25 14 329 -26 131 50 7 128 50 5 132 53 4 127 43 12
129 1 13 -31 0 0 17 27 30 16 330 -28 130 31 3 127 29 14 131 34 32 126 21 34
127 39 7 -30 0 0 17 27 36 17 330 -29 129 9 58 126 5 58 130 14 5 124 57 22
126 14 35 -29 0 0 17 27 43 19 331 -31 127 46 38 124 40 3 128 51 31 123 30 20
124 47 20 -28 0 0 17 27 50 20 332 -32 126 20 49 123 11 11 127 26 38 122 0 8
123 17 6 -27 0 0 17 27 57 22 333 -34 124 52 16 121 39 2 125 59 9 120 26 25
121 43 31 -26 0 0 17 28 6 23 334 -35 123 20 39 120 3 11 124 28 48 118 48 43
120 6 9 -25 0 0 17 28 15 25 335 -37 121 45 37 118 23 9 122 55 15 117 6 31
118 24 31 -24 0 0 17 28 25 26 336 -38 120 6 43 116 38 21 121 18 6 115 19 7
116 38 0 -23 0 0 17 28 37 28 338 -40 118 23 26 114 48 3 119 36 53 113 25 40
114 45 50 -22 0 0 17 28 49 29 339 -41 116 35 9 112 51 19 117 51 2 111 25 6
112 47 2 -21 0 0 17 29 2 31 340 -43 114 41 1 110 46 54 115 59 51 109 15 56
110 40 18 -20 0 0 17 29 17 32 342 -45 112 40 3 108 33 11 114 2 25 106 56 9
Latitude Latitude Latitude Latitude
109 0 0 -19 15 26 17 29 30 33 343 -46 -18 20 19 -20 11 40 -17 41 18 -20 52 54
Uncertainty in time = +/- 7 secs
Prediction of 2009 Nov 15.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
[Top of Page][Return to Home Page]