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Updated: 2009 SEP 02, 15:31 UT
Event Rank : 96
(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 Sep 11 UT, the 121 km diameter asteroid (156) Xanthippe will occult a 12.0 mag star in the constellation Aquila for observers along a fairly broad path across most of the North Island of New Zealand, from Tauranga to Masterton.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.4 mag to 13.0 mag (the magnitude of the asteroid) for at most 29.8 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, 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
176 27 31 -33 29 21 11 38 2 45 298 -60 177 20 13 -33 38 26 175 35 38 -33 20 10 178 5 7 -33 45 59 174 52 39 -33 12 24
176 24 31 -34 40 39 11 38 32 44 299 -59 177 18 14 -34 49 48 175 31 39 -34 31 23 178 4 1 -34 57 25 174 47 52 -34 23 33
176 23 19 -35 52 40 11 39 3 43 300 -58 177 18 8 -36 1 55 175 29 22 -35 43 20 178 4 54 -36 9 36 174 44 42 -35 35 25
176 24 4 -37 5 29 11 39 33 43 301 -57 177 20 7 -37 14 49 175 28 57 -36 56 4 178 7 56 -37 22 34 174 43 20 -36 48 4
176 26 57 -38 19 9 11 40 3 42 301 -55 177 24 20 -38 28 34 175 30 33 -38 9 38 178 13 20 -38 36 24 174 43 53 -38 1 33
176 32 11 -39 33 44 11 40 33 41 302 -54 177 31 3 -39 43 14 175 34 22 -39 24 7 178 21 20 -39 51 8 174 46 33 -39 15 57
176 40 1 -40 49 17 11 41 3 40 303 -53 177 40 31 -40 58 53 175 40 38 -40 39 34 178 32 14 -41 6 51 174 51 34 -40 31 19
176 50 45 -42 5 53 11 41 33 39 303 -52 177 53 4 -42 15 34 175 49 38 -41 56 4 178 46 22 -42 23 37 174 59 10 -41 47 44
177 4 45 -43 23 37 11 42 3 39 304 -51 178 9 4 -43 33 24 176 1 42 -43 13 42 179 4 8 -43 41 31 175 9 41 -43 5 16
177 22 25 -44 42 34 11 42 34 38 304 -49 178 28 59 -44 52 27 176 17 14 -44 32 33 179 26 2 -45 0 38 175 23 29 -44 24 2
177 44 17 -46 2 50 11 43 4 36 305 -48 178 53 23 -46 12 48 176 36 41 -45 52 42 179 52 41 -46 21 4 175 41 0 -45 44 6
178 10 59 -47 24 31 11 43 34 35 305 -47 179 22 57 -47 34 35 177 0 39 -47 14 17 -179 35 13 -47 42 54 176 2 48 -47 5 35
178 43 17 -48 47 43 11 44 4 34 305 -46 179 58 32 -48 57 52 177 29 52 -48 37 24 -178 56 44 -49 6 15 176 29 31 -48 28 35
Uncertainty in time = +/- 14 secs
Prediction of 2009 Sep 2.0
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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