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Updated: 2009 JAN 22, 18:32 UT
Event Rank : 18
(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 Feb 04 UT, the 12 km diameter asteroid (1568) Aisleen will occult a 9.7 mag star in the constellation Cancer for observers along a narrow path across Australia from near Bairnsdale in Victoria past Albury Wodonga to northwestern New South Wales, across Northern Territory into northern Western Australia in evening twilight.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.7 mag to 15.4 mag (the magnitude of the asteroid) for at most 0.8 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 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
152 37 20 -50 0 0 10 44 3 24 43 -11 152 47 16 152 27 23 154 2 4 151 10 30
152 26 21 -49 0 0 10 44 9 25 43 -11 152 36 7 152 16 34 153 49 37 151 1 1
152 13 2 -48 0 0 10 44 15 25 44 -12 152 22 38 152 3 24 153 35 0 150 49 3
151 57 29 -47 0 0 10 44 21 26 44 -12 152 6 57 151 47 59 153 18 16 150 34 43
151 39 47 -46 0 0 10 44 27 26 45 -13 151 49 8 151 30 25 152 59 30 150 18 8
151 20 1 -45 0 0 10 44 33 27 46 -13 151 29 15 151 10 45 152 38 47 149 59 20
150 58 14 -44 0 0 10 44 40 28 46 -14 151 7 22 150 49 4 152 16 10 149 38 24
150 34 28 -43 0 0 10 44 47 28 47 -14 150 43 31 150 25 24 151 51 40 149 15 24
150 8 47 -42 0 0 10 44 53 28 48 -15 150 17 45 149 59 47 151 25 20 148 50 20
149 41 10 -41 0 0 10 45 0 29 49 -15 149 50 5 149 32 14 150 57 11 148 23 16
149 11 39 -40 0 0 10 45 8 29 49 -15 149 20 31 149 2 46 150 27 14 147 54 11
148 40 15 -39 0 0 10 45 15 30 50 -16 148 49 5 148 31 24 149 55 29 147 23 7
148 6 57 -38 0 0 10 45 22 30 51 -16 148 15 44 147 58 7 149 21 56 146 50 2
147 31 43 -37 0 0 10 45 30 30 52 -16 147 40 30 147 22 55 148 46 33 146 14 55
146 54 33 -36 0 0 10 45 38 30 53 -16 147 3 19 146 45 44 148 9 20 145 37 45
146 15 23 -35 0 0 10 45 46 31 54 -17 146 24 10 146 6 34 147 30 13 144 58 30
145 34 11 -34 0 0 10 45 54 31 55 -17 145 42 59 145 25 21 146 49 11 144 17 5
144 50 53 -33 0 0 10 46 2 31 56 -17 144 59 44 144 42 1 146 6 10 143 33 26
144 5 25 -32 0 0 10 46 10 31 57 -17 144 14 18 143 56 30 145 21 5 142 47 29
143 17 40 -31 0 0 10 46 19 31 58 -17 143 26 38 143 8 41 144 33 52 141 59 7
142 27 33 -30 0 0 10 46 27 31 60 -17 142 36 35 142 18 28 143 44 25 141 8 12
141 34 54 -29 0 0 10 46 36 31 61 -16 141 44 2 141 25 43 142 52 35 140 14 35
140 39 34 -28 0 0 10 46 45 30 62 -16 140 48 50 140 30 16 141 58 16 139 18 6
139 41 22 -27 0 0 10 46 54 30 63 -16 139 50 47 139 31 54 141 1 16 138 18 30
138 40 3 -26 0 0 10 47 3 30 64 -16 138 49 39 138 30 25 140 1 23 137 15 32
137 35 22 -25 0 0 10 47 13 29 65 -15 137 45 10 137 25 32 138 58 24 136 8 52
136 26 58 -24 0 0 10 47 22 29 67 -15 136 37 1 136 16 52 137 52 1 134 58 6
135 14 26 -23 0 0 10 47 32 28 68 -14 135 24 47 135 4 2 136 41 52 133 42 43
133 57 14 -22 0 0 10 47 42 28 69 -14 134 7 57 133 46 28 135 27 32 132 22 6
132 34 43 -21 0 0 10 47 52 27 70 -13 132 45 52 132 23 30 134 8 29 130 55 24
131 6 1 -20 0 0 10 48 2 26 71 -12 131 17 42 130 54 15 132 44 1 129 21 29
129 29 57 -19 0 0 10 48 13 25 73 -11 129 42 18 129 17 30 131 13 13 127 38 47
127 44 54 -18 0 0 10 48 24 24 74 -10 127 58 7 127 31 33 129 34 53 125 44 59
125 48 26 -17 0 0 10 48 35 22 75 -9 126 2 48 125 33 52 127 47 16 123 36 27
123 36 42 -16 0 0 10 48 46 20 76 -7 123 52 44 123 20 26 125 47 51 121 6 45
Latitude Latitude Latitude Latitude
122 0 0 -15 21 2 10 48 54 19 77 -6 -15 14 18 -15 27 48 -14 23 41 -16 20 9
121 0 0 -14 58 58 10 48 59 18 77 -5 -14 52 17 -15 5 40 -14 2 7 -15 57 32
120 0 0 -14 38 29 10 49 3 17 78 -4 -14 31 51 -14 45 7 -13 42 4 -15 36 33
Uncertainty in time = +/- 3 secs
[Prediction of 2009 Jan 23.0]
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