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Updated: 2006 OCT 24, 04:02 UT
Event Rank : 5
(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 2006 Nov 01 UT, the 21 km diameter asteroid (4484) Sif will occult a 8.2 mag star in the constellation Grus for observers along a path across north east Western Australia passing near Kununurra in evening twilight.
In the case of an occultation, the combined light of the asteroid and the star will drop by 8.7 mag to 16.9 mag (the magnitude of the asteroid) for at most 1.5 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Ron Stone, 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
129 9 12 11 0 0 10 23 29 30 164 -21 129 15 22 129 3 2 132 1 55 126 13 5
129 13 11 10 0 0 10 23 24 31 163 -21 129 19 19 129 7 2 132 5 17 126 17 42
129 16 45 9 0 0 10 23 20 32 163 -21 129 22 52 129 10 38 132 8 19 126 21 50
129 19 55 8 0 0 10 23 15 33 163 -21 129 26 1 129 13 48 132 11 0 126 25 30
129 22 40 7 0 0 10 23 10 34 163 -20 129 28 46 129 16 35 132 13 21 126 28 42
129 25 2 6 0 0 10 23 5 35 163 -20 129 31 7 129 18 58 132 15 21 126 31 27
129 27 1 5 0 0 10 23 0 36 163 -20 129 33 5 129 20 57 132 17 2 126 33 43
129 28 35 4 0 0 10 22 55 37 162 -20 129 34 39 129 22 32 132 18 22 126 35 33
129 29 47 3 0 0 10 22 50 38 162 -19 129 35 50 129 23 44 132 19 23 126 36 56
129 30 35 2 0 0 10 22 44 39 162 -19 129 36 38 129 24 32 132 20 4 126 37 51
129 31 0 1 0 0 10 22 39 40 162 -19 129 37 2 129 24 57 132 20 25 126 38 19
129 31 1 0 0 0 10 22 33 41 161 -19 129 37 4 129 24 58 132 20 27 126 38 21
129 30 39 - 1 0 0 10 22 28 42 161 -18 129 36 42 129 24 36 132 20 8 126 37 55
129 29 54 - 2 0 0 10 22 22 43 161 -18 129 35 57 129 23 51 132 19 29 126 37 2
129 28 45 - 3 0 0 10 22 16 43 160 -18 129 34 48 129 22 41 132 18 30 126 35 41
129 27 11 - 4 0 0 10 22 10 44 160 -17 129 33 15 129 21 7 132 17 11 126 33 53
129 25 14 - 5 0 0 10 22 4 45 160 -17 129 31 19 129 19 9 132 15 32 126 31 37
129 22 52 - 6 0 0 10 21 57 46 159 -17 129 28 58 129 16 47 132 13 31 126 28 52
129 20 6 - 7 0 0 10 21 51 47 159 -16 129 26 12 129 13 59 132 11 9 126 25 39
129 16 54 - 8 0 0 10 21 45 48 158 -16 129 23 1 129 10 47 132 8 26 126 21 57
129 13 17 - 9 0 0 10 21 38 49 158 -16 129 19 25 129 7 8 132 5 21 126 17 45
129 9 13 -10 0 0 10 21 31 50 157 -15 129 15 23 129 3 3 132 1 54 126 13 3
129 4 43 -11 0 0 10 21 25 51 157 -15 129 10 54 128 58 32 131 58 4 126 7 50
128 59 46 -12 0 0 10 21 18 51 156 -14 129 5 59 128 53 33 131 53 51 126 2 5
128 54 21 -13 0 0 10 21 11 52 156 -14 129 0 35 128 48 6 131 49 14 125 55 49
128 48 27 -14 0 0 10 21 4 53 155 -13 128 54 44 128 42 11 131 44 12 125 48 59
128 42 4 -15 0 0 10 20 57 54 154 -13 128 48 23 128 35 46 131 38 46 125 41 35
128 35 11 -16 0 0 10 20 50 55 153 -13 128 41 32 128 28 50 131 32 54 125 33 37
128 27 47 -17 0 0 10 20 43 56 153 -12 128 34 10 128 21 23 131 26 35 125 25 2
128 19 51 -18 0 0 10 20 35 56 152 -12 128 26 16 128 13 25 131 19 49 125 15 50
128 11 21 -19 0 0 10 20 28 57 151 -11 128 17 50 128 4 52 131 12 35 125 6 0
128 2 17 -20 0 0 10 20 20 58 150 -11 128 8 49 127 55 46 131 4 52 124 55 29
127 52 38 -21 0 0 10 20 13 59 149 -10 127 59 13 127 46 3 130 56 38 124 44 18
127 42 22 -22 0 0 10 20 5 60 148 -10 127 49 0 127 35 44 130 47 53 124 32 24
127 31 28 -23 0 0 10 19 58 60 147 -9 127 38 9 127 24 46 130 38 35 124 19 45
127 19 53 -24 0 0 10 19 50 61 145 -9 127 26 39 127 13 8 130 28 43 124 6 20
127 7 38 -25 0 0 10 19 42 62 144 -8 127 14 27 127 0 48 130 18 17 123 52 6
126 54 39 -26 0 0 10 19 34 62 143 -7 127 1 32 126 47 45 130 7 13 123 37 2
126 40 54 -27 0 0 10 19 26 63 141 -7 126 47 52 126 33 56 129 55 31 123 21 4
126 26 23 -28 0 0 10 19 18 64 140 -6 126 33 25 126 19 20 129 43 9 123 4 12
126 11 1 -29 0 0 10 19 10 64 138 -6 126 18 9 126 3 53 129 30 4 122 46 21
125 54 48 -30 0 0 10 19 2 65 137 -5 126 2 1 125 47 34 129 16 16 122 27 28
125 37 39 -31 0 0 10 18 54 65 135 -5 125 44 58 125 30 20 129 1 41 122 7 32
125 19 33 -32 0 0 10 18 45 66 133 -4 125 26 58 125 12 8 128 46 18 121 46 27
125 0 26 -33 0 0 10 18 37 66 131 -3 125 7 57 124 52 55 128 30 3 121 24 10
124 40 15 -34 0 0 10 18 29 66 129 -3 124 47 53 124 32 37 128 12 54 121 0 37
124 18 56 -35 0 0 10 18 20 67 127 -2 124 26 40 124 11 10 127 54 48 120 35 43
123 56 24 -36 0 0 10 18 12 67 125 -1 124 4 17 123 48 31 127 35 42 120 9 24
123 32 36 -37 0 0 10 18 3 67 123 -1 123 40 37 123 24 35 127 15 31 119 41 33
123 7 26 -38 0 0 10 17 55 68 120 0 123 15 36 122 59 17 126 54 13 119 12 4
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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