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Updated: 2007 MAY 28, 03:25 UT
Event Rank : 14
(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 2007 Jul 01 UT, the 15 km diameter asteroid (531) Zerlina will occult a 9.0 mag star in the constellation Cygnus for observers along a path across central Australia, beginning at Streaky Bay, near Ceduna, and leaving over Admiralty Gulf, in northern Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 7.1 mag to 16.1 mag (the magnitude of the asteroid) for at most 2.3 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 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
141 32 28 -45 0 0 19 22 27 8 334 -29 141 38 54 141 26 3 142 39 4 140 26 14
140 50 24 -44 0 0 19 22 30 10 334 -30 140 56 42 140 44 7 141 55 39 139 45 29
140 9 41 -43 0 0 19 22 33 11 335 -30 140 15 52 140 3 31 141 13 40 139 6 1
139 30 13 -42 0 0 19 22 37 12 335 -30 139 36 17 139 24 10 140 33 1 138 27 42
138 51 55 -41 0 0 19 22 40 13 336 -31 138 57 52 138 45 58 139 53 35 137 50 29
138 14 40 -40 0 0 19 22 45 14 336 -31 138 20 31 138 8 49 139 15 17 137 14 16
137 38 24 -39 0 0 19 22 50 15 336 -31 137 44 9 137 32 38 138 38 1 136 38 59
137 3 2 -38 0 0 19 22 55 16 337 -32 137 8 43 136 57 23 138 1 44 136 4 33
136 28 32 -37 0 0 19 23 0 17 337 -32 136 34 7 136 22 57 137 26 21 135 30 54
135 54 49 -36 0 0 19 23 6 18 337 -32 136 0 19 135 49 19 136 51 47 134 58 0
135 21 49 -35 0 0 19 23 11 19 338 -33 135 27 15 135 16 23 136 18 0 134 25 47
134 49 30 -34 0 0 19 23 18 21 338 -33 134 54 51 134 44 8 135 44 56 133 54 11
134 17 48 -33 0 0 19 23 24 22 338 -33 134 23 5 134 12 31 135 12 32 133 23 11
133 46 41 -32 0 0 19 23 31 23 339 -34 133 51 55 133 41 28 134 40 46 132 52 44
133 16 7 -31 0 0 19 23 39 24 339 -34 133 21 16 133 10 57 134 9 33 132 22 46
132 46 2 -30 0 0 19 23 46 25 339 -34 132 51 9 132 40 56 133 38 53 131 53 17
132 16 25 -29 0 0 19 23 54 26 339 -34 132 21 29 132 11 22 133 8 43 131 24 13
131 47 14 -28 0 0 19 24 2 27 340 -35 131 52 15 131 42 14 132 39 0 130 55 34
131 18 27 -27 0 0 19 24 11 28 340 -35 131 23 25 131 13 30 132 9 43 130 27 16
130 50 2 -26 0 0 19 24 19 29 340 -35 130 54 57 130 45 8 131 40 49 129 59 19
130 21 58 -25 0 0 19 24 28 30 340 -35 130 26 49 130 17 6 131 12 18 129 31 41
129 54 11 -24 0 0 19 24 38 31 340 -35 129 59 1 129 49 22 130 44 6 129 4 20
129 26 43 -23 0 0 19 24 47 32 341 -35 129 31 30 129 21 55 130 16 14 128 37 14
128 59 29 -22 0 0 19 24 57 33 341 -36 129 4 14 128 54 44 129 48 38 128 10 23
128 32 31 -21 0 0 19 25 7 34 341 -36 128 37 14 128 27 48 129 21 18 127 43 45
128 5 45 -20 0 0 19 25 18 36 341 -36 128 10 26 128 1 4 128 54 13 127 17 19
127 39 11 -19 0 0 19 25 29 37 341 -36 127 43 51 127 34 32 128 27 21 126 51 3
127 12 48 -18 0 0 19 25 40 38 341 -36 127 17 26 127 8 10 128 0 41 126 24 57
126 46 34 -17 0 0 19 25 51 39 342 -36 126 51 11 126 41 58 127 34 11 125 58 59
126 20 29 -16 0 0 19 26 2 40 342 -36 126 25 4 126 15 54 127 7 51 125 33 8
125 54 31 -15 0 0 19 26 14 41 342 -36 125 59 5 125 49 58 126 41 39 125 7 24
125 28 40 -14 0 0 19 26 26 42 342 -36 125 33 12 125 24 8 126 15 35 124 41 45
125 2 54 -13 0 0 19 26 38 43 342 -36 125 7 25 124 58 23 125 49 38 124 16 10
124 37 12 -12 0 0 19 26 51 44 342 -36 124 41 43 124 32 42 125 23 46 123 50 39
124 11 35 -11 0 0 19 27 4 45 342 -36 124 16 4 124 7 5 124 57 58 123 25 10
123 45 59 -10 0 0 19 27 17 46 342 -36 123 50 28 123 41 31 124 32 15 122 59 43
Use these links for further information:
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