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Updated: 2009 JUL 29, 23:21 UT
Event Rank : 14
(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 Aug 30 UT, the 32 km diameter asteroid (1013) Tombecka will occult a 12.0 mag star in the constellation Corona Australis for observers along a narrow path across Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.7 mag to 15.6 mag (the magnitude of the asteroid) for at most 6.0 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
114 20 24 -13 0 0 14 40 20 51 224 -64 114 31 48 114 9 3 116 22 38 112 21 19
114 39 14 -14 0 0 14 40 0 51 225 -64 114 50 43 114 27 48 116 42 22 112 39 19
114 59 3 -15 0 0 14 39 40 52 227 -65 115 10 36 114 47 31 117 3 9 112 58 14
115 19 52 -16 0 0 14 39 19 52 228 -65 115 31 31 115 8 14 117 25 1 113 18 5
115 41 44 -17 0 0 14 38 59 53 229 -65 115 53 29 115 30 0 117 48 1 113 38 54
116 4 40 -18 0 0 14 38 38 53 230 -65 116 16 32 115 52 49 118 12 11 114 0 42
116 28 43 -19 0 0 14 38 16 53 231 -65 116 40 43 116 16 46 118 37 34 114 23 33
116 53 56 -20 0 0 14 37 55 54 232 -64 117 6 3 116 41 51 119 4 12 114 47 28
117 20 21 -21 0 0 14 37 34 54 234 -64 117 32 37 117 8 8 119 32 9 115 12 29
117 48 2 -22 0 0 14 37 12 54 235 -64 118 0 26 117 35 40 120 1 28 115 38 40
118 17 1 -23 0 0 14 36 50 55 236 -64 118 29 35 118 4 30 120 32 14 116 6 3
118 47 24 -24 0 0 14 36 28 55 237 -64 119 0 8 118 34 42 121 4 30 116 34 42
Latitude Latitude Latitude Latitude
119 0 0 -24 24 7 14 36 19 55 238 -64 -23 59 45 -24 48 13 -19 50 44 -28 28 22
120 0 0 -26 13 2 14 35 38 55 240 -63 -25 50 4 -26 35 48 -21 57 4 -30 4 50
121 0 0 -27 53 23 14 34 59 55 243 -63 -27 31 35 -28 15 1 -23 51 48 -31 34 28
122 0 0 -29 26 17 14 34 24 55 245 -62 -29 5 29 -29 46 56 -25 36 54 -32 58 1
123 0 0 -30 52 39 14 33 50 55 247 -62 -30 32 44 -31 12 27 -27 13 45 -34 16 7
124 0 0 -32 13 13 14 33 18 55 248 -61 -31 54 4 -32 32 15 -28 43 27 -35 29 20
125 0 0 -33 28 35 14 32 47 55 250 -61 -33 10 7 -33 46 56 -30 6 52 -36 38 6
126 0 0 -34 39 15 14 32 19 55 251 -60 -34 21 24 -34 56 59 -31 24 43 -37 42 48
127 0 0 -35 45 39 14 31 51 54 253 -60 -35 28 22 -36 2 50 -32 37 33 -38 43 46
128 0 0 -36 48 9 14 31 25 54 254 -59 -36 31 22 -37 4 50 -33 45 52 -39 41 19
129 0 0 -37 47 4 14 31 0 53 255 -59 -37 30 45 -38 3 18 -34 50 5 -40 35 41
130 0 0 -38 42 41 14 30 37 53 256 -58 -38 26 48 -38 58 30 -35 50 31 -41 27 7
131 0 0 -39 35 15 14 30 14 53 256 -58 -39 19 45 -39 50 41 -36 47 31 -42 15 49
132 0 0 -40 24 58 14 29 52 52 257 -57 -40 9 50 -40 40 3 -37 41 19 -43 1 57
133 0 0 -41 12 3 14 29 31 52 258 -57 -40 57 15 -41 26 48 -38 32 9 -43 45 42
134 0 0 -41 56 40 14 29 11 51 258 -56 -41 42 11 -42 11 7 -39 20 15 -44 27 13
135 0 0 -42 38 58 14 28 52 50 259 -56 -42 24 46 -42 53 8 -40 5 47 -45 6 37
136 0 0 -43 19 6 14 28 33 50 259 -55 -43 5 10 -43 32 59 -40 48 56 -45 44 2
Uncertainty in time = +/- 29 secs
Prediction of 2009 Jul 29.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
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