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Updated: 2008 JUL 25, 04:56 UT
Event Rank : 92
(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 Aug 23 UT, the 68 km diameter asteroid (304) Olga will occult a 12.8 mag star in the constellation Cetus for observers along a path across Western Australia beginning near Broome and ending over the Nullarbor.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.7 mag to 12.7 mag (the magnitude of the asteroid) for at most 8.2 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: 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
131 19 34 -38 0 0 17 23 35 47 30 -51 130 50 37 131 48 26 130 22 9 132 16 37
130 58 19 -37 0 0 17 23 22 48 31 -52 130 29 41 131 26 51 130 1 31 131 54 44
130 36 44 -36 0 0 17 23 9 49 33 -53 130 8 24 131 4 59 129 40 31 131 32 35
130 14 50 -35 0 0 17 22 56 49 34 -54 129 46 46 130 42 48 129 19 10 131 10 8
129 52 36 -34 0 0 17 22 43 50 35 -54 129 24 47 130 20 19 128 57 26 130 47 23
129 30 1 -33 0 0 17 22 30 51 36 -55 129 2 26 129 57 29 128 35 19 130 24 20
129 7 4 -32 0 0 17 22 16 51 38 -56 128 39 43 129 34 19 128 12 49 130 0 57
128 43 45 -31 0 0 17 22 3 52 39 -57 128 16 36 129 10 48 127 49 54 129 37 14
128 20 4 -30 0 0 17 21 49 52 40 -58 127 53 6 128 46 56 127 26 35 129 13 10
127 55 58 -29 0 0 17 21 35 53 42 -59 127 29 11 128 22 40 127 2 50 128 48 44
127 31 29 -28 0 0 17 21 21 53 43 -59 127 4 51 127 58 1 126 38 39 128 23 56
127 6 33 -27 0 0 17 21 7 54 45 -60 126 40 4 127 32 57 126 14 0 127 58 43
126 41 12 -26 0 0 17 20 52 54 47 -61 126 14 50 127 7 28 125 48 53 127 33 7
126 15 23 -25 0 0 17 20 38 54 48 -62 125 49 7 126 41 32 125 23 17 127 7 4
125 49 5 -24 0 0 17 20 23 55 50 -63 125 22 56 126 15 9 124 57 11 126 40 35
125 22 18 -23 0 0 17 20 9 55 52 -64 124 56 13 125 48 17 124 30 33 126 13 38
124 55 0 -22 0 0 17 19 54 55 53 -64 124 28 59 125 20 55 124 3 23 125 46 12
124 27 10 -21 0 0 17 19 39 55 55 -65 124 1 12 124 53 1 123 35 39 125 18 15
123 58 46 -20 0 0 17 19 24 55 57 -66 123 32 51 124 24 35 123 7 20 124 49 47
123 29 48 -19 0 0 17 19 9 56 59 -67 123 3 54 123 55 35 122 38 23 124 20 46
123 0 13 -18 0 0 17 18 53 56 61 -68 122 34 19 123 26 0 122 8 49 123 51 9
122 30 0 -17 0 0 17 18 38 56 62 -68 122 4 5 122 55 47 121 38 35 123 20 57
121 59 7 -16 0 0 17 18 23 56 64 -69 121 33 11 122 24 56 121 7 39 122 50 6
121 27 33 -15 0 0 17 18 7 55 66 -70 121 1 34 121 53 23 120 36 0 122 18 36
120 55 14 -14 0 0 17 17 52 55 68 -70 120 29 13 121 21 8 120 3 35 121 46 24
Uncertainty in time = +/- 4 secs
[Prediction of 2008 Jul 25.0]
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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