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Updated: 2009 JUN 25, 15:02 UT
Event Rank : 10
(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 Aug 02 UT, the 46 km diameter asteroid (12929) 1999 TZ1 will occult a 11.9 mag star in the constellation Hercules for observers along a narrow and highly uncertain path passing near the east coast of Australia. The uncertainty area extends west past Brisbane, Tamworth, Bathurst, Canberra and Sale. In Tasmania the path is centred just west of Hobart.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.0 mag to 16.8 mag (the magnitude of the asteroid) for at most 3.2 seconds.
This update is based on 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
132 44 38 -58 0 0 9 42 40 1 33 -18 132 15 14 133 13 56 ... .. .. 139 18 50
133 56 3 -57 0 0 9 42 39 2 32 -19 133 27 39 134 24 23 ... .. .. 140 17 46
135 4 3 -56 0 0 9 42 39 3 31 -20 134 36 33 135 31 30 ... .. .. 141 14 17
136 8 59 -55 0 0 9 42 39 4 30 -20 135 42 19 136 35 37 ... .. .. 142 8 36
137 11 10 -54 0 0 9 42 38 5 29 -21 136 45 15 137 37 2 ... .. .. 143 0 57
138 10 51 -53 0 0 9 42 37 6 28 -21 137 45 39 138 36 1 ... .. .. 143 51 31
139 8 17 -52 0 0 9 42 36 8 28 -22 138 43 44 139 32 48 ... .. .. 144 40 29
140 3 40 -51 0 0 9 42 34 9 27 -22 139 39 44 140 27 35 ... .. .. 145 27 58
140 57 13 -50 0 0 9 42 33 10 26 -23 140 33 50 141 20 34 135 34 56 146 14 8
141 49 4 -49 0 0 9 42 31 11 26 -24 141 26 13 142 11 53 136 34 22 146 59 5
142 39 22 -48 0 0 9 42 29 12 25 -24 142 17 1 143 1 42 137 31 44 147 42 57
143 28 17 -47 0 0 9 42 27 13 24 -25 143 6 23 143 50 9 138 27 14 148 25 48
144 15 54 -46 0 0 9 42 25 14 24 -25 143 54 26 144 37 20 139 21 2 149 7 44
145 2 21 -45 0 0 9 42 23 16 23 -26 144 41 17 145 23 23 140 13 15 149 48 51
145 47 43 -44 0 0 9 42 20 17 23 -26 145 27 3 146 8 22 141 4 3 150 29 12
146 32 6 -43 0 0 9 42 17 18 22 -27 146 11 47 146 52 24 141 53 31 151 8 52
147 15 35 -42 0 0 9 42 14 19 22 -27 146 55 37 147 35 33 142 41 47 151 47 54
147 58 15 -41 0 0 9 42 11 20 21 -28 147 38 36 148 17 54 143 28 56 152 26 23
148 40 10 -40 0 0 9 42 8 21 21 -28 148 20 48 148 59 31 144 15 5 153 4 21
149 21 23 -39 0 0 9 42 4 22 20 -29 149 2 18 149 40 27 145 0 17 153 41 51
150 1 58 -38 0 0 9 42 1 23 20 -29 149 43 10 150 20 47 145 44 37 154 18 56
150 41 59 -37 0 0 9 41 57 25 19 -30 150 23 26 151 0 33 146 28 10 154 55 38
151 21 29 -36 0 0 9 41 53 26 19 -30 151 3 10 151 39 49 147 10 59 155 32 1
152 0 31 -35 0 0 9 41 49 27 18 -31 151 42 25 152 18 37 147 53 9 156 8 7
152 39 7 -34 0 0 9 41 45 28 18 -31 152 21 14 152 57 1 148 34 42 156 43 57
153 17 20 -33 0 0 9 41 41 29 17 -32 152 59 38 153 35 2 149 15 41 157 19 34
153 55 13 -32 0 0 9 41 36 30 17 -32 153 37 42 154 12 44 149 56 10 157 55 0
154 32 47 -31 0 0 9 41 31 31 16 -33 154 15 27 154 50 7 150 36 12 158 30 16
155 10 5 -30 0 0 9 41 26 32 16 -33 154 52 55 155 27 16 151 15 49 159 5 25
155 47 9 -29 0 0 9 41 21 33 15 -34 155 30 8 156 4 11 151 55 3 159 40 28
156 24 2 -28 0 0 9 41 16 35 15 -34 156 7 9 156 40 55 152 33 56 160 15 26
157 0 44 -27 0 0 9 41 11 36 15 -35 156 43 59 157 17 29 153 12 32 160 50 23
157 37 17 -26 0 0 9 41 5 37 14 -35 157 20 40 157 53 55 153 50 52 161 25 18
158 13 45 -25 0 0 9 41 0 38 14 -36 157 57 15 158 30 15 154 28 59 162 0 14
158 50 7 -24 0 0 9 40 54 39 13 -36 158 33 43 159 6 31 155 6 53 162 35 12
Uncertainty in time = +/- 25 secs
Prediction of 2009 Jun 25.0
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