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Updated: 2008 SEP 11, 16:16 UT
Event Rank : 15
(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 10 UT, the 40 km diameter asteroid (4460) Bihoro will occult a 10.4 mag star in the constellation Auriga for observers along a large uncertainty path across eastern Northern Territory and north-western Queensland, low in the north.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.7 mag to 16.1 mag (the magnitude of the asteroid) for at most 3.2 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: .
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
133 49 41 -27 0 0 17 53 35 3 21 -34 134 3 14 133 36 9 136 8 37 ... .. ..
134 16 39 -26 0 0 17 53 36 4 21 -35 134 30 5 134 3 14 136 34 30 ... .. ..
134 43 32 -25 0 0 17 53 37 5 21 -35 134 56 52 134 30 12 137 0 21 ... .. ..
135 10 20 -24 0 0 17 53 38 6 21 -35 135 23 34 134 57 6 137 26 12 132 55 4
135 37 5 -23 0 0 17 53 39 8 20 -35 135 50 14 135 23 56 137 52 3 133 22 44
136 3 47 -22 0 0 17 53 40 9 20 -35 136 16 51 135 50 44 138 17 56 133 50 19
136 30 29 -21 0 0 17 53 42 10 20 -35 136 43 28 136 17 30 138 43 52 134 17 48
136 57 11 -20 0 0 17 53 44 11 20 -35 137 10 6 136 44 16 139 9 51 134 45 15
137 23 54 -19 0 0 17 53 46 12 20 -35 137 36 45 137 11 3 139 35 55 135 12 39
137 50 39 -18 0 0 17 53 48 13 20 -35 138 3 27 137 37 52 140 2 5 135 40 2
138 17 28 -17 0 0 17 53 50 14 19 -35 138 30 12 138 4 44 140 28 21 136 7 24
138 44 21 -16 0 0 17 53 53 15 19 -35 138 57 2 138 31 39 140 54 45 136 34 48
139 11 19 -15 0 0 17 53 55 16 19 -35 139 23 58 138 58 40 141 21 18 137 2 15
139 38 24 -14 0 0 17 53 58 17 19 -35 139 51 0 139 25 48 141 48 0 137 29 44
140 5 36 -13 0 0 17 54 2 18 19 -35 140 18 11 139 53 2 142 14 53 137 57 18
140 32 57 -12 0 0 17 54 5 19 19 -35 140 45 31 140 20 25 142 41 59 138 24 57
141 0 28 -11 0 0 17 54 8 21 18 -34 141 13 0 140 47 57 143 9 17 138 52 43
141 28 10 -10 0 0 17 54 12 22 18 -34 141 40 41 141 15 40 143 36 49 139 20 37
Uncertainty in time = +/- 17 secs
[Prediction of 2008 Sep 11.0]
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[Observing Details]
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