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Updated: 2008 SEP 11, 20:26 UT
Event Rank : 50
(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 2008 Oct 16 UT, the 31 km diameter asteroid (852) Wladilena will occult a 10.6 mag star in the constellation Auriga for observers along a path across Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 4.0 mag to 14.6 mag (the magnitude of the asteroid) for at most 2.5 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
115 24 33 -37 0 0 18 49 39 4 23 -30 115 35 55 115 13 9 116 4 45 114 44 10
115 54 14 -36 0 0 18 49 40 5 22 -30 116 5 26 115 43 1 116 33 48 115 14 30
116 22 53 -35 0 0 18 49 40 6 22 -30 116 33 55 116 11 51 117 1 52 115 43 46
116 50 34 -34 0 0 18 49 42 7 22 -31 117 1 26 116 39 42 117 28 59 116 12 1
117 17 21 -33 0 0 18 49 43 8 22 -31 117 28 3 117 6 37 117 55 13 116 39 20
117 43 15 -32 0 0 18 49 44 9 21 -31 117 53 49 117 32 40 118 20 37 117 5 45
118 8 20 -31 0 0 18 49 46 10 21 -32 118 18 46 117 57 54 118 45 14 117 31 20
118 32 40 -30 0 0 18 49 48 12 21 -32 118 42 58 118 22 21 119 9 6 117 56 6
118 56 15 -29 0 0 18 49 50 13 21 -32 119 6 26 118 46 3 119 32 15 118 20 8
119 19 9 -28 0 0 18 49 52 14 20 -32 119 29 13 119 9 4 119 54 45 118 43 26
119 41 23 -27 0 0 18 49 54 15 20 -33 119 51 21 119 31 25 120 16 36 119 6 4
120 3 1 -26 0 0 18 49 56 16 20 -33 120 12 52 119 53 9 120 37 52 119 28 4
120 24 3 -25 0 0 18 49 59 17 20 -33 120 33 48 120 14 17 120 58 33 119 49 27
120 44 31 -24 0 0 18 50 2 18 20 -33 120 54 11 120 34 51 121 18 42 120 10 15
121 4 27 -23 0 0 18 50 4 19 20 -34 121 14 2 120 54 52 121 38 19 120 30 30
121 23 53 -22 0 0 18 50 7 20 20 -34 121 33 23 121 14 23 121 57 28 120 50 14
121 42 50 -21 0 0 18 50 11 21 20 -34 121 52 15 121 33 25 122 16 8 121 9 27
122 1 20 -20 0 0 18 50 14 22 19 -34 122 10 40 121 51 59 122 34 22 121 28 12
122 19 23 -19 0 0 18 50 18 23 19 -34 122 28 39 122 10 6 122 52 11 121 46 30
122 37 1 -18 0 0 18 50 21 24 19 -35 122 46 14 122 27 48 123 9 35 122 4 23
122 54 16 -17 0 0 18 50 25 25 19 -35 123 3 24 122 45 6 123 26 37 122 21 50
123 11 7 -16 0 0 18 50 29 26 19 -35 123 20 13 123 2 2 123 43 17 122 38 54
123 27 37 -15 0 0 18 50 33 27 19 -35 123 36 40 123 18 35 123 59 35 122 55 36
123 43 47 -14 0 0 18 50 37 28 19 -35 123 52 46 123 34 47 124 15 34 123 11 56
123 59 37 -13 0 0 18 50 42 29 19 -35 124 8 33 123 50 40 124 31 14 123 27 56
124 15 8 -12 0 0 18 50 46 30 19 -35 124 24 2 124 6 14 124 46 36 123 43 36
124 30 21 -11 0 0 18 50 51 31 19 -36 124 39 12 124 21 29 125 1 41 123 58 58
124 45 17 -10 0 0 18 50 56 32 19 -36 124 54 6 124 36 28 125 16 30 124 14 2
Uncertainty in time = +/- 3 secs
[Prediction of 2008 Sep 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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