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Updated: 2008 OCT 16, 01:17 UT
Event Rank : 18
(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 24 UT, the 35 km diameter asteroid (4455) Ruriko will occult a 8.7 mag star in the constellation Pisces for observers along a large uncertainty path running down the east coast of Australia from Cairns to eastern Victoria.
In the case of an occultation, the combined light of the asteroid and the star will drop by 7.4 mag to 16.1 mag (the magnitude of the asteroid) for at most 5.3 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
161 24 22 -37 0 0 15 0 33 7 282 -33 160 20 31 162 34 52 154 4 39 ... .. ..
159 51 53 -36 0 0 15 0 21 9 283 -35 158 56 4 160 52 1 153 11 21 ... .. ..
158 37 34 -35 0 0 15 0 8 10 283 -36 157 47 7 159 31 10 152 25 43 ... .. ..
157 36 28 -34 0 0 14 59 55 11 284 -38 156 49 53 158 25 29 151 46 39 168 5 55
156 45 40 -33 0 0 14 59 41 12 284 -39 156 2 2 157 31 19 151 13 20 165 35 59
156 3 18 -32 0 0 14 59 27 13 284 -40 155 21 58 156 46 20 150 45 9 163 58 24
155 28 5 -31 0 0 14 59 12 14 285 -41 154 48 35 156 9 3 150 21 36 162 46 8
154 59 3 -30 0 0 14 58 58 14 285 -42 154 21 4 155 38 22 150 2 16 161 50 14
154 35 32 -29 0 0 14 58 42 15 285 -43 153 58 46 155 13 30 149 46 51 161 6 22
154 16 59 -28 0 0 14 58 27 16 285 -44 153 41 13 154 53 51 149 35 3 160 32 2
154 2 59 -27 0 0 14 58 12 16 284 -45 153 28 3 154 38 57 149 26 41 160 5 41
153 53 13 -26 0 0 14 57 56 17 284 -46 153 18 57 154 28 27 149 21 34 159 46 14
153 47 25 -25 0 0 14 57 40 17 284 -47 153 13 42 154 22 4 149 19 32 159 32 57
153 45 24 -24 0 0 14 57 24 17 284 -48 153 12 7 154 19 37 149 20 29 159 25 19
153 47 2 -23 0 0 14 57 7 18 284 -49 153 14 3 154 20 55 149 24 20 159 22 58
153 52 11 -22 0 0 14 56 51 18 283 -50 153 19 24 154 25 51 149 31 1 159 25 40
154 0 48 -21 0 0 14 56 34 18 283 -51 153 28 7 154 34 21 149 40 28 159 33 16
154 12 50 -20 0 0 14 56 17 18 283 -51 153 40 10 154 46 24 149 52 40 159 45 45
154 28 19 -19 0 0 14 56 0 18 282 -52 153 55 33 155 2 0 150 7 38 160 3 10
154 47 16 -18 0 0 14 55 42 18 282 -53 154 14 18 155 21 10 150 25 21 160 25 39
Uncertainty in time = +/- 24 secs
[Prediction of 2008 Oct 16.0]
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
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