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Updated: 2013 JUL 30, 05:16 UT
Event Rank : 28
(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 2013 Sep 12 UT, the 32 km diameter asteroid (533) Sara will occult a 12.0 mag star in the constellation Sagittarius for observers along a narrow path across eastern Queensland from Byron Bay, just west of Brisbane and running parallel to the caost about 200-300 km inlamd to south of Weipa.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.8 mag to 14.7 mag (the magnitude of the asteroid) for at most 9.0 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, 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
138 41 4 -10 0 0 13 19 21 55 258 -69 138 29 26 138 52 45 137 33 36 139 49 45
139 9 2 -11 0 0 13 19 56 54 260 -69 138 57 15 139 20 52 138 0 44 140 18 37
139 38 25 -12 0 0 13 20 32 54 261 -69 139 26 28 139 50 24 138 29 11 140 48 58
140 9 17 -13 0 0 13 21 7 53 262 -70 139 57 10 140 21 27 138 59 4 141 20 54
Latitude Latitude Latitude Latitude
141 0 0 -14 32 27 13 22 2 53 264 -70 -14 54 9 -14 10 31 -16 36 18 -12 21 4
142 0 0 -16 13 8 13 23 2 52 266 -70 -16 33 39 -15 52 27 -18 10 24 -14 9 29
143 0 0 -17 45 39 13 23 58 50 268 -70 -18 5 8 -17 26 1 -19 37 15 -15 48 32
144 0 0 -19 11 1 13 24 50 49 269 -70 -19 29 36 -18 52 17 -20 57 41 -17 19 32
145 0 0 -20 30 4 13 25 38 48 270 -69 -20 47 53 -20 12 8 -22 12 25 -18 43 29
146 0 0 -21 43 31 13 26 23 47 271 -69 -22 0 38 -21 26 17 -23 22 1 -20 1 13
147 0 0 -22 51 54 13 27 5 46 272 -69 -23 8 24 -22 35 17 -24 26 59 -21 13 25
148 0 0 -23 55 43 13 27 45 45 272 -68 -24 11 41 -23 39 40 -25 27 45 -22 20 37
149 0 0 -24 55 24 13 28 22 44 273 -68 -25 10 52 -24 39 50 -26 24 39 -23 23 20
150 0 0 -25 51 16 13 28 58 43 273 -67 -26 6 18 -25 36 10 -27 18 2 -24 21 57
151 0 0 -26 43 40 13 29 31 42 273 -67 -26 58 17 -26 28 58 -28 8 9 -25 16 49
152 0 0 -27 32 50 13 30 3 41 274 -66 -27 47 5 -27 18 30 -28 55 14 -26 8 14
153 0 0 -28 19 1 13 30 32 39 274 -66 -28 32 56 -28 5 2 -29 39 32 -26 56 29
154 0 0 -29 2 25 13 31 1 38 274 -65 -29 16 2 -28 48 45 -30 21 11 -27 41 46
155 0 0 -29 43 14 13 31 28 37 274 -64 -29 56 34 -29 29 51 -31 0 24 -28 24 18
156 0 0 -30 21 37 13 31 53 36 273 -64 -30 34 42 -30 8 30 -31 37 19 -29 4 16
157 0 0 -30 57 43 13 32 18 35 273 -63 -31 10 33 -30 44 50 -32 12 3 -29 41 49
Uncertainty in time = +/- 23 secs
Prediction of 2013 Jul 7.0
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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