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Updated: 2009 JAN 22, 18:03 UT
Event Rank : 100
(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 Jan 29 UT, the 208 km diameter asteroid (13) Egeria will occult a 9.1 mag star in the constellation Ursa Major for observers along a very wide path across Northern Territory, including Darwin, western and south-western Queensland, north-eastern and eastern South Australia, western New South Wales and nearly all of Victoria, including directly over Melbourne.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.5 mag to 10.3 mag (the magnitude of the asteroid) for at most 24.9 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, 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
145 33 23 -45 0 0 15 9 24 8 21 -27 148 17 19 142 38 19 148 55 15 141 54 19
145 41 56 -44 0 0 15 9 28 9 21 -28 148 22 41 142 50 33 148 59 56 142 7 33
145 47 28 -43 0 0 15 9 32 10 21 -29 148 25 21 142 59 23 149 1 58 142 17 14
145 50 8 -42 0 0 15 9 37 11 21 -30 148 25 28 143 4 59 149 1 29 142 23 37
145 50 5 -41 0 0 15 9 42 11 21 -31 148 23 7 143 7 33 148 58 38 142 26 53
145 47 28 -40 0 0 15 9 47 12 21 -32 148 18 26 143 7 14 148 53 29 142 27 10
145 42 21 -39 0 0 15 9 53 13 21 -33 148 11 30 143 4 9 148 46 8 142 24 36
145 34 50 -38 0 0 15 10 0 14 21 -34 148 2 23 142 58 25 148 36 40 142 19 20
145 25 0 -37 0 0 15 10 7 15 22 -35 147 51 9 142 50 6 148 25 7 142 11 25
145 12 55 -36 0 0 15 10 14 16 22 -36 147 37 52 142 39 19 148 11 33 142 0 56
144 58 36 -35 0 0 15 10 22 17 22 -37 147 22 33 142 26 4 147 56 0 141 47 58
144 42 7 -34 0 0 15 10 30 18 22 -38 147 5 15 142 10 26 147 38 30 141 32 33
144 23 29 -33 0 0 15 10 39 18 23 -39 146 45 59 141 52 26 147 19 5 141 14 41
144 2 43 -32 0 0 15 10 48 19 23 -40 146 24 45 141 32 5 146 57 44 140 54 25
143 39 49 -31 0 0 15 10 57 20 24 -41 146 1 35 141 9 22 146 34 30 140 31 45
143 14 47 -30 0 0 15 11 7 21 24 -42 145 36 27 140 44 18 146 9 20 140 6 39
142 47 35 -29 0 0 15 11 18 22 24 -43 145 9 21 140 16 51 145 42 14 139 39 6
142 18 11 -28 0 0 15 11 28 22 25 -44 144 40 15 139 46 58 145 13 11 139 9 4
141 46 34 -27 0 0 15 11 40 23 26 -45 144 9 8 139 14 36 144 42 9 138 36 28
141 12 39 -26 0 0 15 11 52 24 26 -46 143 35 56 138 39 41 144 9 6 138 1 15
140 36 23 -25 0 0 15 12 4 24 27 -47 143 0 37 138 2 6 143 33 58 137 23 18
139 57 40 -24 0 0 15 12 17 25 27 -48 142 23 6 137 21 46 142 56 41 136 42 29
139 16 24 -23 0 0 15 12 31 26 28 -49 141 43 17 136 38 31 142 17 10 135 58 40
138 32 26 -22 0 0 15 12 45 26 29 -50 141 1 6 135 52 12 141 35 20 135 11 39
137 45 39 -21 0 0 15 12 59 27 30 -51 140 16 24 135 2 35 140 51 4 134 21 12
136 55 49 -20 0 0 15 13 14 27 31 -52 139 29 4 134 9 24 140 4 14 133 27 3
136 2 45 -19 0 0 15 13 30 28 31 -53 138 38 54 133 12 22 139 14 39 132 28 50
135 6 9 -18 0 0 15 13 47 28 32 -54 137 45 43 132 11 3 138 22 10 131 26 6
134 5 41 -17 0 0 15 14 4 29 33 -55 136 49 17 131 4 57 137 26 32 130 18 18
133 0 56 -16 0 0 15 14 22 29 34 -56 135 49 17 129 53 26 136 27 28 129 4 42
131 51 22 -15 0 0 15 14 41 29 35 -57 134 45 22 128 35 39 135 24 40 127 44 19
130 36 20 -14 0 0 15 15 1 29 37 -58 133 37 6 127 10 24 134 17 41 126 15 47
129 14 55 -13 0 0 15 15 23 29 38 -59 132 23 54 125 36 5 133 6 3 124 37 6
127 45 56 -12 0 0 15 15 45 29 39 -60 131 5 4 123 50 12 131 49 6 122 45 13
126 7 41 -11 0 0 15 16 9 29 40 -60 129 39 38 121 48 43 130 25 59 120 34 48
124 17 34 -10 0 0 15 16 35 29 42 -61 128 6 20 119 24 15 128 55 34 117 55 8
122 11 26 - 9 0 0 15 17 3 28 43 -61 126 23 18 116 19 39 127 16 18 114 15 52
121 0 0 - 8 29 55 15 17 19 28 44 -61 - 6 30 1 -10 38 26 - 6 2 20 -11 10 48
120 0 0 - 8 6 44 15 17 31 27 45 -61 - 6 8 4 -10 13 45 - 5 40 38 -10 45 42
Uncertainty in time = +/- 4 secs
[Prediction of 2009 Jan 23.0]
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