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Updated: 2009 MAY 18, 00:31 UT
Event Rank : 45
(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 Jun 24 UT, the 30 km diameter asteroid (1609) Brenda will occult a 11.7 mag star in the constellation Serpens for observers along a path across Australia, from near Cairns in northern Queensland at low elevation across central Northern Territory and southern Western Australia to Bunbury, with Perth just on the one sigma limit.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.7 mag to 13.1 mag (the magnitude of the asteroid) for at most 2.6 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
145 36 58 -15 22 5 19 37 25 8 258 -16 146 26 0 -15 17 7 144 52 23 -15 25 57 149 38 19 -14 50 6 143 0 3 -15 32 52
141 49 3 -16 52 36 19 37 35 12 259 -19 142 22 0 -16 51 43 141 17 29 -16 53 8 144 7 31 -16 46 39 139 52 24 -16 53 2
139 0 48 -18 8 0 19 37 44 14 260 -22 139 27 50 -18 8 40 138 34 30 -18 7 9 140 51 15 -18 9 19 137 22 3 -18 3 44
136 41 8 -19 16 7 19 37 54 17 261 -25 137 4 56 -19 17 39 136 17 51 -19 14 27 138 17 9 -19 21 18 135 12 57 -19 8 58
134 39 7 -20 19 43 19 38 4 19 262 -27 135 0 48 -20 21 51 134 17 49 -20 17 30 136 6 4 -20 27 24 133 18 1 -20 10 35
132 49 21 -21 20 11 19 38 13 21 263 -29 133 9 33 -21 22 44 132 29 27 -21 17 34 134 9 59 -21 29 40 131 33 23 -21 9 33
131 8 42 -22 18 19 19 38 23 22 263 -30 131 27 47 -22 21 12 130 49 52 -22 15 22 132 24 41 -22 29 11 129 56 38 -22 6 29
129 35 10 -23 14 37 19 38 32 24 264 -32 129 53 24 -23 17 46 129 17 10 -23 11 24 130 47 33 -23 26 37 128 26 9 -23 1 48
128 7 22 -24 9 27 19 38 42 25 265 -34 128 24 54 -24 12 51 127 50 2 -24 6 1 129 16 54 -24 22 24 127 0 49 -23 55 49
126 44 18 -25 3 6 19 38 51 26 266 -35 127 1 17 -25 6 41 126 27 30 -24 59 28 127 51 32 -25 16 50 125 39 45 -24 48 43
125 25 13 -25 55 44 19 39 1 27 267 -36 125 41 44 -25 59 29 125 8 52 -25 51 56 126 30 34 -26 10 11 124 22 21 -25 40 43
124 9 33 -26 47 31 19 39 11 29 268 -37 124 25 40 -26 51 26 123 53 34 -26 43 34 125 13 19 -27 2 35 123 8 4 -26 31 55
122 56 49 -27 38 35 19 39 20 30 269 -39 123 12 37 -27 42 38 122 41 9 -27 34 29 123 59 15 -27 54 13 121 56 31 -27 22 27
121 46 39 -28 29 1 19 39 30 31 270 -40 122 2 10 -28 33 12 121 31 15 -28 24 48 122 47 58 -28 45 11 120 47 21 -28 12 24
120 38 44 -29 18 55 19 39 39 32 271 -41 120 54 2 -29 23 13 120 23 34 -29 14 35 121 39 7 -29 35 34 119 40 17 -29 1 51
119 32 50 -30 8 21 19 39 49 33 272 -42 119 47 56 -30 12 46 119 17 51 -30 3 54 120 32 25 -30 25 27 118 35 6 -29 50 51
118 28 42 -30 57 22 19 39 59 33 273 -43 118 43 38 -31 1 54 118 13 53 -30 52 49 119 27 37 -31 14 55 117 31 35 -30 39 29
117 26 10 -31 46 3 19 40 8 34 274 -44 117 40 57 -31 50 41 117 11 29 -31 41 24 118 24 31 -32 4 0 116 29 33 -31 27 46
116 25 3 -32 34 26 19 40 18 35 276 -45 116 39 44 -32 39 10 116 10 29 -32 29 40 117 22 56 -32 52 46 115 28 53 -32 15 46
115 25 13 -33 22 33 19 40 27 36 277 -45 115 39 48 -33 27 22 115 10 45 -33 17 42 116 22 42 -33 41 16 114 29 24 -33 3 31
114 26 33 -34 10 27 19 40 37 36 278 -46 114 41 3 -34 15 22 114 12 9 -34 5 30 115 23 43 -34 29 32 113 31 0 -33 51 4
113 28 54 -34 58 9 19 40 47 37 279 -47 113 43 21 -35 3 10 113 14 34 -34 53 7 114 25 50 -35 17 36 112 33 36 -34 38 26
112 32 12 -35 45 43 19 40 56 38 280 -48 112 46 36 -35 50 49 112 17 55 -35 40 35 113 28 56 -36 5 30 111 37 3 -35 25 39
111 36 20 -36 33 8 19 41 6 38 281 -48 111 50 42 -36 38 20 111 22 5 -36 27 56 112 32 57 -36 53 17 110 41 18 -36 12 45
Uncertainty in time = +/- 4 secs
Prediction of 2009 May 18.0
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