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Updated: 2010 AUG 20, 01:56 UT
Event Rank : 83
(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 Oct 06 UT, the 65 km diameter asteroid (258) Tyche will occult a 11.7 mag star in the constellation Taurus for observers along a slow path across eastern Australia, running across central Queensland, western New South Wales and western Victoria, passing over Mackay, Horsham and Mount Gambier.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.7 mag to 11.6 mag (the magnitude of the asteroid) for at most 9.6 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 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
150 19 38 -19 30 36 15 1 23 48 35 -59 150 39 21 -19 31 58 149 59 53 -19 29 16 151 4 8 -19 33 45 149 34 54 -19 27 39
149 39 54 -21 15 6 15 1 46 47 35 -58 149 59 54 -21 16 26 149 19 51 -21 13 48 150 25 3 -21 18 11 148 54 29 -21 12 14
148 57 14 -23 2 15 15 2 9 45 35 -57 149 17 35 -23 3 32 148 36 51 -23 0 59 149 43 8 -23 5 14 148 11 3 -22 59 28
148 11 11 -24 52 22 15 2 32 43 34 -56 148 31 55 -24 53 37 147 50 24 -24 51 10 148 57 57 -24 55 15 147 24 6 -24 49 43
147 21 8 -26 45 54 15 2 54 41 34 -55 147 42 19 -26 47 6 146 59 54 -26 44 46 148 8 54 -26 48 39 146 33 1 -26 43 24
146 26 20 -28 43 21 15 3 17 39 34 -53 146 48 2 -28 44 28 146 4 34 -28 42 18 147 15 17 -28 45 57 145 37 0 -28 41 2
145 25 47 -30 45 21 15 3 40 37 34 -52 145 48 6 -30 46 22 145 3 22 -30 44 23 146 16 6 -30 47 44 144 35 0 -30 43 14
144 18 6 -32 52 42 15 4 3 35 35 -50 144 41 11 -32 53 36 143 54 56 -32 51 51 145 10 6 -32 54 50 143 25 36 -32 50 52
143 1 26 -35 6 29 15 4 25 32 35 -48 143 25 25 -35 7 14 142 37 21 -35 5 47 143 55 28 -35 8 17 142 6 48 -35 5 1
141 33 3 -37 28 9 15 4 48 30 35 -46 141 58 10 -37 28 42 141 7 46 -37 27 41 142 29 38 -37 29 30 140 35 43 -37 27 12
139 48 44 -39 59 49 15 5 11 27 36 -44 140 15 21 -40 0 4 139 21 55 -39 59 39 140 48 39 -40 0 31 138 47 52 -39 59 36
137 41 34 -42 44 45 15 5 34 24 37 -42 138 10 17 -42 44 33 137 12 37 -42 45 4 138 46 6 -42 44 28 136 35 46 -42 45 38
Uncertainty in time = +/- 6 secs
Prediction of 2010 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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