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Updated: 2008 OCT 20, 22:43 UT
Event Rank : 34
(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 2008 Dec 01 UT, the 22 km diameter asteroid (897) Lysistrata will occult a 10.0 mag star in the constellation Aries for observers along a path beginning over far north Queensland passing just north of Cooktown. Moving south-west the path passes through the Northern Territory near Tennant Creek. Then into Western Australia passing near Kalgoorlie before ending near Albany.
In the case of an occultation, the combined light of the asteroid and the star will drop by 4.3 mag to 14.3 mag (the magnitude of the asteroid) for at most 1.7 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
113 3 49 -43 0 0 16 8 32 19 342 -25 112 47 16 113 20 28 111 44 5 114 25 30
113 31 8 -42 0 0 16 8 26 20 342 -26 113 14 42 113 47 39 112 12 1 114 52 11
114 0 19 -41 0 0 16 8 20 21 341 -27 113 44 0 114 16 44 112 41 43 115 20 52
114 31 23 -40 0 0 16 8 14 22 340 -28 114 15 8 114 47 42 113 13 12 115 51 31
115 4 19 -39 0 0 16 8 7 23 340 -29 114 48 8 115 20 34 113 46 27 116 24 9
115 39 8 -38 0 0 16 8 0 23 339 -30 115 23 0 115 55 21 114 21 30 116 58 46
116 15 51 -37 0 0 16 7 52 24 338 -31 115 59 45 116 32 3 114 58 21 117 35 24
116 54 31 -36 0 0 16 7 44 25 338 -32 116 38 25 117 10 43 115 37 2 118 14 5
117 35 10 -35 0 0 16 7 36 26 337 -33 117 19 2 117 51 23 116 17 36 118 54 53
118 17 51 -34 0 0 16 7 28 26 336 -34 118 1 41 118 34 7 117 0 5 119 37 49
119 2 39 -33 0 0 16 7 19 27 335 -35 118 46 24 119 18 59 117 44 34 120 23 0
119 49 38 -32 0 0 16 7 10 28 334 -36 119 33 18 120 6 4 118 31 7 121 10 30
120 38 54 -31 0 0 16 7 1 28 333 -37 120 22 27 120 55 29 119 19 49 122 0 27
121 30 35 -30 0 0 16 6 51 29 332 -38 121 13 58 121 47 19 120 10 47 122 52 58
122 24 49 -29 0 0 16 6 41 29 331 -39 122 8 0 122 41 44 121 4 8 123 48 13
123 21 45 -28 0 0 16 6 30 30 330 -40 123 4 42 123 38 55 122 0 1 124 46 23
124 21 35 -27 0 0 16 6 19 30 329 -40 124 4 16 124 39 3 122 58 35 125 47 42
125 24 35 -26 0 0 16 6 8 31 328 -41 125 6 56 125 42 22 124 0 5 126 52 27
126 31 0 -25 0 0 16 5 56 31 327 -42 126 12 58 126 49 11 125 4 43 128 0 56
127 41 11 -24 0 0 16 5 43 31 325 -43 127 22 42 127 59 51 126 12 49 129 13 36
128 55 34 -23 0 0 16 5 31 31 324 -43 128 36 32 129 14 48 127 24 42 130 30 56
130 14 41 -22 0 0 16 5 17 32 322 -44 129 54 59 130 34 36 128 40 50 131 53 36
131 39 11 -21 0 0 16 5 3 32 321 -45 131 18 42 131 59 55 130 1 45 133 22 27
133 9 58 -20 0 0 16 4 48 31 319 -45 132 48 30 133 31 43 131 28 9 134 58 37
134 48 11 -19 0 0 16 4 33 31 318 -45 134 25 30 135 11 12 133 0 56 136 43 40
136 35 28 -18 0 0 16 4 16 31 316 -45 136 11 14 137 0 9 134 41 20 138 39 57
138 34 15 -17 0 0 16 3 59 30 314 -45 138 7 56 139 1 9 136 31 3 140 51 4
140 48 19 -16 0 0 16 3 39 29 313 -45 140 19 4 141 18 22 138 32 36 143 23 23
Latitude Latitude Latitude Latitude
141 0 0 -15 55 9 16 3 38 29 312 -45 -15 42 49 -16 7 33 -14 55 57 -16 56 12
142 0 0 -15 31 9 16 3 30 29 312 -45 -15 18 57 -15 43 26 -14 32 31 -16 31 35
143 0 0 -15 8 41 16 3 21 28 311 -45 -14 56 35 -15 20 51 -14 10 34 -16 8 33
144 0 0 -14 47 43 16 3 14 28 310 -45 -14 35 44 -14 59 47 -13 50 5 -15 47 5
145 0 0 -14 28 15 16 3 6 27 310 -44 -14 16 20 -14 40 13 -13 31 2 -15 27 8
146 0 0 -14 10 14 16 2 58 27 309 -44 -13 58 24 -14 22 7 -13 13 24 -15 8 41
147 0 0 -13 53 39 16 2 51 26 308 -43 -13 41 55 -14 5 28 -12 57 11 -14 51 44
Uncertainty in time = +/- 3 secs
[Prediction of 2008 Oct 20.0]
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