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Updated: 2010 MAR 18, 19:48 UT
Event Rank : 21
(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 2010 May 10 UT, the 22 km diameter asteroid (1236) Thais will occult a 9.6 mag star in the constellation Sagittarius for observers along a very narrow path across the North Island of New Zealand, from Wellington to Mangonui, passing near Hawera. ( About half the North Island, including Auckland, is within the one sigma limit )
In the case of an occultation, the combined light of the asteroid and the star will drop by 6.1 mag to 15.7 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: 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
173 14 30 -33 0 0 16 33 7 81 264 -32 173 7 16 173 21 43 172 20 0 174 9 10
173 25 26 -34 0 0 16 33 24 81 270 -32 173 18 7 173 32 44 172 30 15 174 20 48
173 36 56 -35 0 0 16 33 40 81 276 -32 173 29 31 173 44 20 172 41 2 174 33 2
173 49 2 -36 0 0 16 33 57 80 282 -32 173 41 31 173 56 32 172 52 22 174 45 54
174 1 46 -37 0 0 16 34 13 80 287 -31 173 54 9 174 9 23 173 4 18 174 59 27
174 15 11 -38 0 0 16 34 30 79 292 -31 174 7 27 174 22 54 173 16 52 175 13 43
174 29 18 -39 0 0 16 34 46 79 296 -31 174 21 28 174 37 9 173 30 7 175 28 45
174 44 12 -40 0 0 16 35 2 78 300 -31 174 36 14 174 52 10 173 44 4 175 44 36
174 59 54 -41 0 0 16 35 19 77 303 -30 174 51 48 175 8 0 173 58 47 176 1 18
175 16 28 -42 0 0 16 35 35 76 306 -30 175 8 13 175 24 43 174 14 18 176 18 56
175 33 57 -43 0 0 16 35 52 76 308 -30 175 25 34 175 42 21 174 30 41 176 37 33
175 52 26 -44 0 0 16 36 8 75 310 -29 175 43 54 176 0 59 174 47 59 176 57 13
Uncertainty in time = +/- 11 secs
Prediction of 2010 Mar 18.0
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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