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Updated: 2006 DEC 15, 05:04 UT
Event Rank : 8
(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 2007 Jan 12 UT, the 13 km diameter asteroid (7887) Bratfest will occult a 10.2 mag star in the constellation Auriga for observers along a narrow path of large uncertainty across far south-east South Australia, western Victoria, central New South Wales and south-east Queensland.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.1 mag to 15.3 mag (the magnitude of the asteroid) for at most 1.2 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: 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
135 34 40 -43 0 0 11 52 18 13 27 -12 135 26 24 135 42 57 133 6 49 138 4 22
136 40 36 -42 0 0 11 52 14 14 26 -13 136 32 25 136 48 48 134 14 16 139 8 52
137 46 31 -41 0 0 11 52 10 16 25 -14 137 38 24 137 54 38 135 21 32 140 13 30
138 52 29 -40 0 0 11 52 5 17 25 -15 138 44 26 139 0 33 136 28 44 141 18 20
139 58 36 -39 0 0 11 52 0 18 24 -17 139 50 37 140 6 36 137 35 56 142 23 28
141 4 56 -38 0 0 11 51 54 19 23 -18 140 57 0 141 12 53 138 43 13 143 28 57
142 11 35 -37 0 0 11 51 49 21 22 -19 142 3 41 142 19 29 139 50 40 144 34 53
143 18 36 -36 0 0 11 51 42 22 21 -21 143 10 44 143 26 28 140 58 22 145 41 19
144 26 5 -35 0 0 11 51 35 23 21 -22 144 18 15 144 33 55 142 6 23 146 48 22
145 34 6 -34 0 0 11 51 28 24 20 -23 145 26 17 145 41 55 143 14 49 147 56 5
146 42 44 -33 0 0 11 51 21 26 19 -25 146 34 56 146 50 33 144 23 45 149 4 34
147 52 6 -32 0 0 11 51 13 27 18 -26 147 44 18 147 59 54 145 33 15 150 13 54
149 2 14 -31 0 0 11 51 4 28 17 -28 148 54 27 149 10 3 146 43 24 151 24 10
150 13 17 -30 0 0 11 50 56 29 16 -29 150 5 28 150 21 6 147 54 19 152 35 29
151 25 18 -29 0 0 11 50 46 31 15 -30 151 17 28 151 33 8 149 6 4 153 47 57
152 38 25 -28 0 0 11 50 36 32 14 -32 152 30 33 152 46 17 150 18 45 155 1 39
153 52 43 -27 0 0 11 50 26 33 13 -33 153 44 49 154 0 38 151 32 28 156 16 45
155 8 21 -26 0 0 11 50 16 34 12 -35 155 0 24 155 16 18 152 47 21 157 33 21
156 25 25 -25 0 0 11 50 4 35 11 -36 156 17 25 156 33 26 154 3 29 158 51 35
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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