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Updated: 2009 AUG 20, 11:54 UT
Event Rank : 95
(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 18 11 -33 29 33 11 38 3 45 298 -60 177 10 45 -33 38 39 175 26 25 -33 20 21 177 56 37 -33 46 24 174 42 30 -33 12 23
176 15 3 -34 40 59 11 38 33 44 299 -59 177 8 38 -34 50 10 175 22 17 -34 31 42 177 55 24 -34 57 58 174 37 33 -34 23 39
176 13 42 -35 53 9 11 39 3 44 300 -58 177 8 24 -36 2 25 175 19 52 -35 43 47 177 56 10 -36 10 18 174 34 15 -35 35 40
176 14 18 -37 6 7 11 39 34 43 301 -57 177 10 13 -37 15 28 175 19 18 -36 56 40 177 59 5 -37 23 25 174 32 42 -36 48 28
176 17 2 -38 19 56 11 40 4 42 302 -55 177 14 17 -38 29 22 175 20 45 -38 10 23 178 4 21 -38 37 23 174 33 5 -38 2 6
176 22 6 -39 34 39 11 40 34 41 302 -54 177 20 50 -39 44 11 175 24 24 -39 25 1 178 12 13 -39 52 17 174 35 34 -39 16 38
176 29 46 -40 50 22 11 41 4 40 303 -53 177 30 8 -40 59 59 175 30 31 -40 40 38 178 22 58 -41 8 10 174 40 23 -40 32 10
176 40 20 -42 7 8 11 41 34 40 304 -52 177 42 30 -42 16 51 175 39 21 -41 57 18 178 36 57 -42 25 6 174 47 47 -41 48 44
176 54 8 -43 25 2 11 42 5 39 304 -51 177 58 18 -43 34 51 175 51 14 -43 15 6 178 54 34 -43 43 11 174 58 6 -43 6 27
177 11 37 -44 44 10 11 42 35 38 304 -49 178 18 2 -44 54 5 176 6 34 -44 34 7 179 16 19 -45 2 29 175 11 40 -44 25 22
177 33 16 -46 4 38 11 43 5 37 305 -48 178 42 14 -46 14 38 176 25 49 -45 54 28 179 42 48 -46 23 6 175 28 57 -45 45 37
177 59 46 -47 26 30 11 43 35 35 305 -47 179 11 35 -47 36 36 176 49 35 -47 16 15 -179 45 15 -47 45 9 175 50 29 -47 7 18
178 31 51 -48 49 56 11 44 5 34 305 -45 179 46 56 -49 0 7 177 18 35 -48 39 34 -179 6 56 -49 8 43 176 16 57 -48 30 31
Uncertainty in time = +/- 14 secs
Prediction of 2009 Aug 20.0
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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