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Updated: 2015 JUL 17, 17:09 UT
Event Rank : 99
(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 2015 Aug 06 UT, the 95 km diameter asteroid (313) Chaldaea will occult a 10.0 mag star in the constellation Aquila for observers along a path over South Australia near Ceduna and Woomera.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.1 mag to 13.0 mag (the magnitude of the asteroid) for at most 7.6 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: .
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
154 1 41 -27 23 50 18 39 29 1 263 -23 ... .. .. .. .. .. 147 43 3 -27 41 18 ... .. .. .. .. .. 146 6 55 -27 39 21
146 35 24 -28 41 26 18 39 37 7 267 -29 150 43 58 -28 39 8 143 53 23 -28 33 49 ... .. .. .. .. .. 142 45 43 -28 28 30
143 9 46 -29 31 22 18 39 44 10 268 -32 145 42 26 -29 40 18 141 4 36 -29 19 20 147 16 59 -29 42 41 140 8 43 -29 12 35
140 31 3 -30 15 56 18 39 52 13 270 -35 142 33 24 -30 28 32 138 44 12 -30 1 37 143 42 51 -30 33 54 137 55 6 -29 53 59
138 16 34 -30 57 44 18 39 59 15 271 -37 140 2 38 -31 12 23 136 41 6 -30 41 56 141 0 49 -31 19 9 135 56 32 -30 33 42
136 17 32 -31 37 48 18 40 6 16 272 -38 137 53 7 -31 53 51 134 49 57 -31 20 55 138 44 35 -32 1 29 134 8 38 -31 12 14
134 29 23 -32 16 40 18 40 14 18 273 -40 135 57 33 -32 33 45 133 7 38 -31 58 57 136 44 29 -32 42 0 132 28 49 -31 49 53
132 49 25 -32 54 40 18 40 21 19 275 -41 134 12 2 -33 12 34 131 32 12 -32 36 14 134 55 40 -33 21 17 130 55 21 -32 26 52
131 15 54 -33 31 58 18 40 29 20 276 -42 132 34 10 -33 50 34 130 2 18 -33 12 57 133 15 17 -33 59 40 129 27 3 -33 3 18
129 47 36 -34 8 46 18 40 36 21 277 -43 131 2 22 -34 27 56 128 36 58 -33 49 13 131 41 29 -34 37 22 128 3 1 -33 39 20
128 23 37 -34 45 7 18 40 44 22 278 -44 129 35 31 -35 4 49 127 15 27 -34 25 7 130 13 0 -35 14 32 126 42 37 -34 15 1
127 3 17 -35 21 9 18 40 51 23 279 -45 128 12 47 -35 41 19 125 57 12 -35 0 43 128 48 56 -35 51 17 125 25 18 -34 50 25
125 46 5 -35 56 55 18 40 59 24 280 -46 126 53 32 -36 17 30 124 41 46 -35 36 5 127 28 33 -36 27 42 124 10 41 -35 25 35
124 31 34 -36 32 27 18 41 6 25 281 -47 125 37 17 -36 53 27 123 28 47 -36 11 15 126 11 21 -37 3 51 122 58 24 -36 0 35
123 19 24 -37 7 49 18 41 13 26 282 -48 124 23 38 -37 29 12 122 17 57 -36 46 16 124 56 52 -37 39 48 121 48 11 -36 35 26
Uncertainty in time = +/- 2 secs
Prediction of 2015 Jul 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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