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Updated: 2009 DEC 11, 00:45 UT
Event Rank : 27
(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 Feb 03 UT, the 16 km diameter asteroid (502) Sigune will occult a 11.2 mag star in the constellation Leo for observers along a path across Western Australia from Balladonia, passing near Leonora, and ending between Karratha and Port Hedland.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.0 mag to 13.0 mag (the magnitude of the asteroid) for at most 1.2 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
131 31 6 -42 29 36 20 1 25 16 318 -4 131 21 55 -42 28 5 131 40 20 -42 31 8 130 37 18 -42 20 57 132 26 43 -42 39 4
128 30 30 -39 10 48 20 1 36 20 319 -8 128 22 39 -39 9 48 128 38 23 -39 11 48 127 44 18 -39 5 6 129 17 44 -39 17 0
126 16 9 -36 17 58 20 1 48 24 321 -11 126 9 3 -36 17 15 126 23 15 -36 18 41 125 34 19 -36 13 53 126 58 40 -36 22 24
124 29 5 -33 41 47 20 1 59 27 321 -13 124 22 30 -33 41 15 124 35 41 -33 42 19 123 50 11 -33 38 45 125 8 31 -33 45 6
123 0 12 -31 17 30 20 2 11 29 322 -15 122 53 59 -31 17 6 123 6 26 -31 17 55 122 23 25 -31 15 12 123 37 25 -31 20 2
121 44 21 -29 2 17 20 2 22 32 322 -17 121 38 24 -29 1 58 121 50 19 -29 2 36 121 9 10 -29 0 31 122 19 52 -29 4 15
120 38 19 -26 54 16 20 2 33 34 322 -19 120 32 35 -26 54 1 120 44 3 -26 54 31 120 4 25 -26 52 55 121 12 31 -26 55 48
119 39 57 -24 52 8 20 2 45 36 322 -21 119 34 24 -24 51 57 119 45 31 -24 52 20 119 7 5 -24 51 7 120 13 4 -24 53 20
118 47 45 -22 54 57 20 2 56 38 322 -23 118 42 21 -22 54 49 118 53 10 -22 55 5 118 15 45 -22 54 11 119 19 59 -22 55 51
118 0 37 -21 1 57 20 3 8 40 322 -24 117 55 20 -21 1 51 118 5 54 -21 2 3 117 29 20 -21 1 25 118 32 6 -21 2 38
117 17 43 -19 12 35 20 3 19 42 321 -26 117 12 33 -19 12 31 117 22 54 -19 12 39 116 47 3 -19 12 14 117 48 35 -19 13 4
116 38 26 -17 26 22 20 3 31 43 321 -27 116 33 20 -17 26 20 116 43 31 -17 26 25 116 8 16 -17 26 11 117 8 45 -17 26 41
116 2 14 -15 42 57 20 3 42 45 321 -28 115 57 13 -15 42 56 116 7 15 -15 42 58 115 32 31 -15 42 53 116 32 6 -15 43 7
115 28 44 -14 1 59 20 3 53 47 320 -30 115 23 47 -14 1 59 115 33 41 -14 1 59 114 59 24 -14 2 2 115 58 12 -14 2 2
114 57 36 -12 23 13 20 4 5 48 319 -31 114 52 43 -12 23 14 115 2 30 -12 23 12 114 28 37 -12 23 23 115 26 44 -12 23 9
Uncertainty in time = +/- 3 secs
Prediction of 2009 Dec 11.0
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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