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Updated: 2012 JUL 07, 23:01 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 2012 Aug 09 UT, the 352 km diameter asteroid (52) Europa will occult a 12.9 mag star in the constellation Ophiuchus for observers along a wide path running down western WA from Exmouth to near Hopetoun on the south coast. Perth is inside the 1-sigma uncertainty area.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.4 mag to 12.0 mag (the magnitude of the asteroid) for at most 90.5 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
112 52 25 -16 0 0 13 50 1 67 264 -51 111 3 57 114 42 35 109 55 21 115 54 5
113 6 22 -17 0 0 13 50 30 67 266 -51 111 17 2 114 57 29 110 7 53 116 9 37
113 21 6 -18 0 0 13 51 0 67 268 -51 111 30 48 115 13 12 110 21 5 116 26 1
113 36 37 -19 0 0 13 51 31 66 270 -52 111 45 19 115 29 48 110 34 59 116 43 21
113 52 59 -20 0 0 13 52 1 66 272 -52 112 0 37 115 47 18 110 49 37 117 1 38
114 10 13 -21 0 0 13 52 31 66 274 -53 112 16 43 116 5 47 111 5 1 117 20 56
114 28 24 -22 0 0 13 53 1 65 276 -53 112 33 40 116 25 15 111 21 14 117 41 18
114 47 32 -23 0 0 13 53 31 65 278 -53 112 51 30 116 45 48 111 38 17 118 2 47
115 7 43 -24 0 0 13 54 1 64 280 -54 113 10 18 117 7 27 111 56 14 118 25 28
115 28 58 -25 0 0 13 54 31 63 282 -54 113 30 4 117 30 18 112 15 8 118 49 23
115 51 22 -26 0 0 13 55 1 63 283 -54 113 50 54 117 54 24 112 35 0 119 14 38
116 14 59 -27 0 0 13 55 31 62 284 -55 114 12 50 118 19 49 112 55 55 119 41 18
116 39 52 -28 0 0 13 56 1 61 286 -55 114 35 56 118 46 38 113 17 57 120 9 27
117 6 7 -29 0 0 13 56 31 61 287 -55 115 0 17 119 14 57 113 41 9 120 39 11
117 33 48 -30 0 0 13 57 1 60 288 -55 115 25 56 119 44 51 114 5 35 121 10 36
118 3 2 -31 0 0 13 57 31 59 289 -55 115 52 59 120 16 27 114 31 19 121 43 50
118 33 54 -32 0 0 13 58 1 58 290 -56 116 21 31 120 49 51 114 58 28 122 19 1
Latitude Latitude Latitude Latitude
119 0 0 -32 48 18 13 58 25 57 291 -56 -36 43 58 -28 28 44 -39 5 13 -25 25 37
120 0 0 -34 31 41 13 59 16 56 292 -56 -38 14 16 -30 29 11 -40 28 33 -27 40 14
121 0 0 -36 5 48 14 0 3 54 293 -56 -39 37 9 -32 17 34 -41 45 22 -29 40 7
122 0 0 -37 31 59 14 0 45 53 293 -56 -40 53 34 -33 55 53 -42 56 26 -31 27 59
123 0 0 -38 51 17 14 1 25 52 294 -56 -42 4 18 -35 25 39 -44 2 24 -33 5 50
124 0 0 -40 4 34 14 2 1 50 294 -56 -43 9 59 -36 48 3 -45 3 49 -34 35 10
125 0 0 -41 12 30 14 2 34 49 294 -56 -44 11 8 -38 4 1 -46 1 9 -35 57 9
126 0 0 -42 15 41 14 3 5 48 294 -56 -45 8 14 -39 14 21 -46 54 46 -37 12 46
Uncertainty in time = +/- 29 secs
Prediction of 2012 Jul 8.0
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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