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Updated: 2009 DEC 27, 13:01 UT
Event Rank : 65
(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 2010 Jan 14 UT, the 83 km diameter asteroid (71) Niobe will occult a 13.0 mag star in the constellation Auriga for observers along a path across Queensland, western New South Wales, western Victoria, southern South Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by only 0.3 mag to 11.6 mag (the magnitude of the asteroid) for at most 5.4 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
137 44 49 -41 0 0 12 10 17 3 16 -17 136 59 29 138 30 31 ... .. .. 139 55 35
138 13 8 -40 0 0 12 10 16 4 16 -18 137 28 14 138 58 23 ... .. .. 140 22 39
138 42 17 -39 0 0 12 10 16 6 15 -19 137 57 47 139 27 8 ... .. .. 140 50 39
139 12 16 -38 0 0 12 10 14 7 15 -20 138 28 8 139 56 46 137 7 48 141 19 37
139 43 6 -37 0 0 12 10 13 8 15 -21 138 59 18 140 27 16 137 39 34 141 49 31
140 14 47 -36 0 0 12 10 12 9 14 -22 139 31 17 140 58 40 138 12 6 142 20 23
140 47 21 -35 0 0 12 10 10 10 14 -23 140 4 6 141 30 58 138 45 24 142 52 13
141 20 47 -34 0 0 12 10 8 11 14 -24 140 37 46 142 4 11 139 19 30 143 25 2
141 55 7 -33 0 0 12 10 6 12 13 -25 141 12 18 142 38 20 139 54 24 143 58 50
142 30 23 -32 0 0 12 10 3 13 13 -26 141 47 43 143 13 26 140 30 8 144 33 40
143 6 35 -31 0 0 12 10 0 14 13 -27 142 24 3 143 49 30 141 6 43 145 9 32
143 43 45 -30 0 0 12 9 58 15 12 -28 143 1 18 144 26 35 141 44 10 145 46 27
144 21 55 -29 0 0 12 9 54 16 12 -29 143 39 32 145 4 41 142 22 32 146 24 29
145 1 6 -28 0 0 12 9 51 17 11 -30 144 18 45 145 43 51 143 1 50 147 3 38
145 41 21 -27 0 0 12 9 47 18 11 -32 144 59 0 146 24 7 143 42 6 147 43 57
146 22 43 -26 0 0 12 9 43 20 11 -33 145 40 19 147 5 32 144 23 22 148 25 29
147 5 13 -25 0 0 12 9 39 21 10 -34 146 22 45 147 48 7 145 5 41 149 8 16
147 48 54 -24 0 0 12 9 35 22 10 -35 147 6 19 148 31 56 145 49 5 149 52 21
148 33 51 -23 0 0 12 9 30 23 9 -36 147 51 7 149 17 2 146 33 38 150 37 48
149 20 5 -22 0 0 12 9 25 24 9 -38 148 37 10 150 3 29 147 19 22 151 24 41
150 7 42 -21 0 0 12 9 20 25 8 -39 149 24 32 150 51 21 148 6 21 152 13 4
150 56 45 -20 0 0 12 9 15 26 8 -40 150 13 18 151 40 43 148 54 38 153 3 3
151 47 19 -19 0 0 12 9 9 27 7 -41 151 3 32 152 31 38 149 44 19 153 54 41
152 39 29 -18 0 0 12 9 3 28 6 -43 151 55 20 153 24 13 150 35 27 154 48 6
Uncertainty in time = +/- 5 secs
Prediction of 2009 Dec 27.0
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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