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Updated: 2009 AUG 20, 19:02 UT
Event Rank : 29
(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 Sep 28 UT, the 49 km diameter asteroid (2951) Perepadin will occult a 9.2 mag star in the constellation Sagittarius for observers along a narrow path of significant uncertainty across Western Australia from Hpoetoun to Fitzroy Crossing.
In the case of an occultation, the combined light of the asteroid and the star will drop by 6.8 mag to 16.0 mag (the magnitude of the asteroid) for at most 5.6 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: .
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
125 47 4 -11 0 0 11 18 0 64 178 -27 126 0 43 125 33 24 127 4 33 124 29 22
125 37 41 -12 0 0 11 17 48 65 178 -26 125 51 23 125 23 58 126 55 29 124 19 40
125 28 6 -13 0 0 11 17 36 66 177 -26 125 41 52 125 14 20 126 46 14 124 9 45
125 18 19 -14 0 0 11 17 24 67 177 -26 125 32 9 125 4 29 126 36 49 123 59 36
125 8 19 -15 0 0 11 17 12 68 176 -25 125 22 14 124 54 25 126 27 13 123 49 12
124 58 6 -16 0 0 11 16 59 69 175 -25 125 12 4 124 44 6 126 17 24 123 38 32
124 47 37 -17 0 0 11 16 47 70 174 -24 125 1 41 124 33 33 126 7 23 123 27 36
124 36 54 -18 0 0 11 16 35 71 174 -24 124 51 2 124 22 44 125 57 8 123 16 22
124 25 54 -19 0 0 11 16 22 72 173 -24 124 40 8 124 11 39 125 46 39 123 4 51
124 14 36 -20 0 0 11 16 10 73 172 -23 124 28 56 124 0 16 125 35 55 122 53 0
124 3 1 -21 0 0 11 15 57 74 170 -23 124 17 27 123 48 34 125 24 54 122 40 48
123 51 6 -22 0 0 11 15 44 75 169 -22 124 5 39 123 36 32 125 13 37 122 28 15
123 38 51 -23 0 0 11 15 31 76 167 -22 123 53 31 123 24 10 125 2 1 122 15 20
123 26 14 -24 0 0 11 15 19 77 166 -21 123 41 2 123 11 26 124 50 6 122 2 0
123 13 15 -25 0 0 11 15 6 78 163 -21 123 28 10 122 58 19 124 37 51 121 48 16
122 59 52 -26 0 0 11 14 53 78 161 -20 123 14 55 122 44 47 124 25 15 121 34 5
122 46 3 -27 0 0 11 14 40 79 158 -20 123 1 15 122 30 50 124 12 15 121 19 26
122 31 47 -28 0 0 11 14 27 80 155 -20 122 47 9 122 16 25 123 58 52 121 4 17
122 17 4 -29 0 0 11 14 14 81 151 -19 122 32 35 122 1 31 123 45 3 120 48 36
122 1 50 -30 0 0 11 14 0 81 146 -19 122 17 31 121 46 7 123 30 47 120 32 23
121 46 4 -31 0 0 11 13 47 82 140 -18 122 1 57 121 30 10 123 16 3 120 15 34
121 29 44 -32 0 0 11 13 34 82 134 -18 121 45 49 121 13 39 123 0 48 119 58 9
121 12 49 -33 0 0 11 13 21 83 126 -17 121 29 5 120 56 32 122 45 0 119 40 4
120 55 16 -34 0 0 11 13 7 83 117 -16 121 11 45 120 38 46 122 28 39 119 21 17
120 37 3 -35 0 0 11 12 54 83 108 -16 120 53 45 120 20 19 122 11 41 119 1 45
120 18 6 -36 0 0 11 12 41 83 99 -15 120 35 3 120 1 8 121 54 5 118 41 27
119 58 25 -37 0 0 11 12 27 83 90 -15 120 15 36 119 41 12 121 35 48 118 20 18
119 37 54 -38 0 0 11 12 14 82 83 -14 119 55 22 119 20 25 121 16 46 117 58 16
119 16 32 -39 0 0 11 12 1 82 76 -14 119 34 17 118 58 47 120 56 58 117 35 17
Uncertainty in time = +/- 14 secs
Prediction of 2009 Aug 21.0
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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