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Updated: 2011 FEB 18, 23:04 UT
Event Rank : 84
(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 2011 Mar 07 UT, the 105 km diameter asteroid (1269) Rollandia will occult a 11.6 mag star in the constellation Gemini for observers along a fairly broad path across Western Australia, from Esperance to Wickham.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.2 mag to 14.7 mag (the magnitude of the asteroid) for at most 90.6 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, 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
123 34 35 -36 0 0 11 18 50 32 13 -13 124 19 42 122 49 17 125 15 24 121 52 49
123 15 3 -35 0 0 11 19 46 33 13 -13 123 59 44 122 30 11 124 54 53 121 34 16
122 54 40 -34 0 0 11 20 43 34 14 -14 123 38 56 122 10 13 124 33 34 121 14 50
122 33 28 -33 0 0 11 21 42 34 14 -14 123 17 20 121 49 24 124 11 30 120 54 30
122 11 27 -32 0 0 11 22 43 35 14 -14 122 54 57 121 27 46 123 48 39 120 33 19
121 48 38 -31 0 0 11 23 44 36 14 -14 122 31 47 121 5 18 123 25 4 120 11 18
121 25 2 -30 0 0 11 24 48 37 15 -14 122 7 52 120 42 1 123 0 44 119 48 26
121 0 40 -29 0 0 11 25 52 38 15 -14 121 43 11 120 17 58 122 35 41 119 24 46
120 35 32 -28 0 0 11 26 58 39 16 -15 121 17 46 119 53 7 122 9 54 119 0 17
120 9 39 -27 0 0 11 28 6 40 16 -15 120 51 37 119 27 31 121 43 25 118 35 1
119 43 2 -26 0 0 11 29 15 41 16 -15 120 24 45 119 1 9 121 16 14 118 8 58
119 15 41 -25 0 0 11 30 25 42 17 -15 119 57 9 118 34 2 120 48 22 117 42 9
118 47 36 -24 0 0 11 31 37 43 17 -15 119 28 52 118 6 11 120 19 48 117 14 34
118 18 49 -23 0 0 11 32 49 44 18 -15 118 59 52 117 37 36 119 50 33 116 46 15
117 49 19 -22 0 0 11 34 4 45 18 -15 118 30 11 117 8 17 119 20 38 116 17 10
117 19 7 -21 0 0 11 35 19 46 19 -15 117 59 48 116 38 15 118 50 2 115 47 21
116 48 13 -20 0 0 11 36 36 46 19 -15 117 28 45 116 7 31 118 18 47 115 16 49
116 16 37 -19 0 0 11 37 53 47 20 -15 116 57 0 115 36 4 117 46 52 114 45 32
115 44 20 -18 0 0 11 39 13 48 21 -15 116 24 35 115 3 54 117 14 17 114 13 32
115 11 21 -17 0 0 11 40 33 49 21 -15 115 51 30 114 31 3 116 41 3 113 40 50
Uncertainty in time = +/- 57 secs
Prediction of 2011 Feb 11.0
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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