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Updated: 2011 Sep 23, 22:33 UT
Event Rank : 83
(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 Oct 22 UT, the 61 km diameter asteroid (342) Endymion will occult a 11.0 mag star in the constellation Pisces for observers along a path across Northern Territory and eastern West Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.4 mag to 14.3 mag (the magnitude of the asteroid) for at most 10.3 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, 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.
Occultation of UCAC2 32638043 by 342 Endymion on 2011 Oct 22
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
122 40 39 -37 0 0 13 44 20 48 337 -36 122 15 32 123 5 50 121 43 56 123 37 38
123 5 22 -36 0 0 13 44 3 49 336 -37 122 40 30 123 30 17 122 9 15 124 1 45
123 30 24 -35 0 0 13 43 46 50 335 -38 123 5 48 123 55 4 122 34 52 124 26 12
123 55 45 -34 0 0 13 43 29 51 334 -39 123 31 23 124 20 11 123 0 45 124 51 1
124 21 26 -33 0 0 13 43 12 51 333 -40 123 57 18 124 45 38 123 26 56 125 16 12
124 47 27 -32 0 0 13 42 54 52 332 -41 124 23 31 125 11 27 123 53 26 125 41 45
125 13 49 -31 0 0 13 42 36 53 330 -42 124 50 5 125 37 37 124 20 14 126 7 40
125 40 32 -30 0 0 13 42 18 54 329 -43 125 16 58 126 4 8 124 47 21 126 33 58
126 7 35 -29 0 0 13 42 0 54 328 -44 125 44 12 126 31 2 125 14 48 127 0 39
126 35 1 -28 0 0 13 41 41 55 327 -45 126 11 47 126 58 18 125 42 35 127 27 43
127 2 49 -27 0 0 13 41 22 55 325 -46 126 39 44 127 25 57 126 10 43 127 55 11
127 30 59 -26 0 0 13 41 3 56 324 -47 127 8 2 127 53 59 126 39 12 128 23 3
127 59 33 -25 0 0 13 40 44 57 322 -48 127 36 44 128 22 26 127 8 3 128 51 20
128 28 31 -24 0 0 13 40 25 57 321 -49 128 5 48 128 51 17 127 37 16 129 20 3
128 57 53 -23 0 0 13 40 6 58 319 -50 128 35 17 129 20 33 128 6 53 129 49 11
129 27 41 -22 0 0 13 39 46 58 317 -51 129 5 10 129 50 15 128 36 53 130 18 46
129 57 54 -21 0 0 13 39 26 59 316 -52 129 35 28 130 20 24 129 7 17 130 48 49
130 28 34 -20 0 0 13 39 7 59 314 -53 130 6 13 130 50 59 129 38 7 131 19 19
130 59 42 -19 0 0 13 38 47 59 312 -54 130 37 24 131 22 3 130 9 23 131 50 18
131 31 17 -18 0 0 13 38 26 60 310 -55 131 9 3 131 53 36 130 41 6 132 21 47
132 3 22 -17 0 0 13 38 6 60 308 -56 131 41 10 132 25 38 131 13 16 132 53 47
132 35 57 -16 0 0 13 37 46 60 306 -57 132 13 46 132 58 11 131 45 55 133 26 17
133 9 3 -15 0 0 13 37 25 61 304 -58 132 46 53 133 31 15 132 19 4 133 59 20
133 42 40 -14 0 0 13 37 4 61 302 -59 133 20 32 134 4 53 132 52 44 134 32 57
134 16 51 -13 0 0 13 36 44 61 300 -60 133 54 43 134 39 4 133 26 55 135 7 8
134 51 37 -12 0 0 13 36 23 61 298 -61 134 29 28 135 13 50 134 1 39 135 41 55
135 26 57 -11 0 0 13 36 2 61 296 -62 135 4 47 135 49 12 134 36 57 136 17 19
136 2 55 -10 0 0 13 35 41 61 294 -64 135 40 43 136 25 11 135 12 51 136 53 21
Uncertainty in time = +/- 7 secs
Prediction of 2011 Sep 24.0
Use these links for further information:
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[Observing Details]
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