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Updated: 2010 FEB 18, 21:23 UT
Event Rank : 100
(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 Mar 01 UT, the 222 km diameter asteroid (532) Herculina will occult a 10.1 mag star in the constellation Coma Berenices for observers along a fairly broad path across Western Australia, from Onslow to Esperence.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.3 mag to 8.9 mag (the magnitude of the asteroid) for at most 23.6 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
125 35 11 -39 0 0 19 6 2 23 335 -25 127 5 2 124 5 46 127 21 15 123 49 43
124 52 30 -38 0 0 19 6 8 24 335 -26 126 20 56 123 24 29 126 36 53 123 8 40
124 10 45 -37 0 0 19 6 13 25 336 -27 125 37 50 122 44 2 125 53 33 122 28 28
123 29 52 -36 0 0 19 6 19 26 336 -28 124 55 40 122 4 23 125 11 9 121 49 1
122 49 46 -35 0 0 19 6 25 27 337 -29 124 14 22 121 25 26 124 29 38 121 10 17
122 10 24 -34 0 0 19 6 31 28 337 -30 123 33 52 120 47 10 123 48 56 120 32 13
121 31 42 -33 0 0 19 6 37 29 337 -31 122 54 7 120 9 30 123 8 59 119 54 44
120 53 38 -32 0 0 19 6 44 30 338 -32 122 15 3 119 32 25 122 29 44 119 17 49
120 16 8 -31 0 0 19 6 51 32 338 -33 121 36 36 118 55 50 121 51 7 118 41 24
119 39 10 -30 0 0 19 6 58 33 339 -34 120 58 45 118 19 45 121 13 6 118 5 27
119 2 42 -29 0 0 19 7 5 34 339 -35 120 21 26 117 44 5 120 35 38 117 29 57
118 26 40 -28 0 0 19 7 13 35 339 -36 119 44 37 117 8 50 119 58 40 116 54 49
117 51 3 -27 0 0 19 7 20 36 340 -37 119 8 15 116 33 56 119 22 10 116 20 4
117 15 48 -26 0 0 19 7 28 37 340 -38 118 32 19 115 59 22 118 46 6 115 45 37
116 40 54 -25 0 0 19 7 36 38 340 -39 117 56 45 115 25 7 118 10 25 115 11 28
116 6 18 -24 0 0 19 7 45 39 341 -40 117 21 33 114 51 7 117 35 6 114 37 35
115 32 0 -23 0 0 19 7 53 40 341 -41 116 46 39 114 17 22 117 0 6 114 3 56
114 57 56 -22 0 0 19 8 2 42 341 -42 116 12 3 113 43 50 116 25 23 113 30 29
114 24 5 -21 0 0 19 8 11 43 342 -43 115 37 42 113 10 28 115 50 57 112 57 13
113 50 27 -20 0 0 19 8 20 44 342 -44 115 3 35 112 37 17 115 16 45 112 24 7
113 16 58 -19 0 0 19 8 29 45 342 -45 114 29 40 112 4 14 114 42 46 111 51 8
112 43 38 -18 0 0 19 8 38 46 343 -46 113 55 56 111 31 18 114 8 57 111 18 16
112 10 26 -17 0 0 19 8 48 47 343 -47 113 22 22 110 58 27 113 35 18 110 45 29
111 37 19 -16 0 0 19 8 57 48 343 -48 112 48 55 110 25 40 113 1 47 110 12 45
111 4 17 -15 0 0 19 9 7 49 344 -49 112 15 34 109 52 56 112 28 23 109 40 4
Uncertainty in time = +/- 3 secs
Prediction of 2010 Feb 19.0
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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