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Updated: 2009 DEC 10, 12:08 UT
Event Rank : 47
(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 28 UT, the 29 km diameter asteroid (273) Atropos will occult a 11.1 mag star in the constellation Hydra for observers along a path grazing the southern tip of New Zealand.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.1 mag to 14.1 mag (the magnitude of the asteroid) for at most 2.0 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
166 45 29 -47 0 0 9 39 25 26 56 -10 167 19 18 166 11 15 168 51 19 164 33 47
165 33 19 -46 0 0 9 39 35 25 57 -10 166 7 23 164 58 50 167 39 57 163 20 30
164 17 41 -45 0 0 9 39 44 25 59 -10 164 52 6 163 42 50 166 25 29 162 3 18
162 58 17 -44 0 0 9 39 54 25 60 -10 163 33 9 162 22 55 165 7 39 160 41 47
161 34 44 -43 0 0 9 40 4 25 62 -10 162 10 12 160 58 44 163 46 10 159 15 32
160 6 34 -42 0 0 9 40 14 24 63 -10 160 42 48 159 29 45 162 20 39 157 43 55
158 33 13 -41 0 0 9 40 25 24 65 -9 159 10 25 157 55 21 160 50 38 156 6 10
156 53 55 -40 0 0 9 40 36 23 67 -9 157 32 20 156 14 43 159 15 32 154 21 17
155 7 40 -39 0 0 9 40 46 22 68 -8 155 47 39 154 26 47 157 34 36 152 27 51
153 13 7 -38 0 0 9 40 58 21 70 -7 153 55 6 152 30 3 155 46 52 150 23 52
151 8 22 -37 0 0 9 41 9 20 72 -6 151 53 0 150 22 23 153 51 1 148 6 18
150 0 0 -36 29 25 9 41 15 19 73 -6 -36 9 4 -36 50 4 -35 13 53 -37 49 6
149 0 0 -36 3 54 9 41 20 18 73 -5 -35 43 47 -36 24 19 -34 49 12 -37 22 37
148 0 0 -35 39 36 9 41 25 18 74 -5 -35 19 41 -35 59 47 -34 25 40 -36 57 25
Uncertainty in time = +/- 3 secs
Prediction of 2009 Dec 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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