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Updated: 2008 JUL 10, 06:24 UT
Event Rank : 99
(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 16 UT, the 120 km diameter asteroid (141) Lumen will occult a 11.9 mag star in the constellation Aries for observers along a path across south-eastTasmania passing near Hobart.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.8 mag to 12.0 mag (the magnitude of the asteroid) for at most 9.5 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
143 34 10 -47 0 0 15 34 56 7 41 -54 144 37 44 142 29 56 145 10 32 141 56 15
144 50 55 -46 0 0 15 34 58 8 40 -54 145 52 35 143 48 39 146 24 26 143 16 1
146 4 16 -45 0 0 15 35 0 10 39 -55 147 4 12 145 3 48 147 35 9 144 32 8
147 14 31 -44 0 0 15 35 2 11 39 -55 148 12 51 146 15 42 148 43 0 145 44 55
148 21 56 -43 0 0 15 35 4 12 38 -55 149 18 48 147 24 39 149 48 12 146 54 40
149 26 47 -42 0 0 15 35 7 14 37 -56 150 22 17 148 30 54 150 50 59 148 1 40
150 29 16 -41 0 0 15 35 9 15 36 -56 151 23 30 149 34 40 151 51 34 149 6 8
151 29 34 -40 0 0 15 35 12 16 36 -56 152 22 38 150 36 11 152 50 6 150 8 18
152 27 53 -39 0 0 15 35 16 17 35 -56 153 19 50 151 35 37 153 46 45 151 8 19
153 24 20 -38 0 0 15 35 19 19 34 -56 154 15 16 152 33 7 154 41 40 152 6 23
154 19 5 -37 0 0 15 35 23 20 34 -56 155 9 4 153 28 51 155 34 58 153 2 37
155 12 15 -36 0 0 15 35 26 21 33 -56 156 1 21 154 22 56 156 26 47 153 57 11
156 3 57 -35 0 0 15 35 31 22 33 -56 156 52 13 155 15 29 157 17 14 154 50 12
156 54 18 -34 0 0 15 35 35 24 32 -56 157 41 47 156 6 38 158 6 24 155 41 46
157 43 23 -33 0 0 15 35 39 25 32 -56 158 30 8 156 56 28 158 54 22 156 31 59
Uncertainty in time = +/- 3 secs
[Prediction of 2008 Jul 10.0]
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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