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Updated: 2010 APR 15, 17:22 UT
Event Rank : 76
(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 Apr 22 UT, the 116 km diameter asteroid (68) Leto will occult a 13.2 mag star in the constellation Ophiuchus for observers along a path across Northern Territory and Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.2 mag to 11.6 mag (the magnitude of the asteroid) for at most 30.3 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 Limit1 Path Limit2 Error Limit1 Error Limit2
E. Longitude Latitude U.T. Alt Az Alt
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
132 36 46 - 9 39 44 15 10 3 35 118 -87 133 27 16 - 9 56 12 131 45 19 - 9 22 37 134 39 24 -10 19 7 130 28 19 - 8 56 19
132 27 50 -10 37 49 15 10 29 36 117 -88 133 18 10 -10 54 8 131 36 33 -10 20 51 134 30 8 -11 16 52 130 19 52 - 9 54 49
132 17 38 -11 35 16 15 10 55 36 116 -89 133 7 52 -11 51 28 131 26 30 -11 18 26 134 19 43 -12 14 2 130 10 4 -10 52 38
132 6 13 -12 32 8 15 11 21 36 116 -89 132 56 23 -12 48 14 131 15 11 -12 15 25 134 8 10 -13 10 40 129 58 55 -11 49 49
131 53 35 -13 28 27 15 11 48 37 115 -88 132 43 43 -13 44 27 131 2 36 -13 11 49 133 55 28 -14 6 47 129 46 27 -12 46 22
131 39 45 -14 24 13 15 12 14 37 114 -88 132 29 52 -14 40 10 130 48 47 -14 7 40 133 41 39 -15 2 25 129 32 42 -13 42 19
131 24 42 -15 19 29 15 12 40 37 114 -87 132 14 52 -15 35 23 130 33 43 -15 2 59 133 26 43 -15 57 35 129 17 38 -14 37 43
131 8 27 -16 14 15 15 13 6 37 113 -86 131 58 40 -16 30 8 130 17 25 -15 57 47 133 10 38 -16 52 18 129 1 17 -15 32 35
130 50 59 -17 8 33 15 13 33 38 112 -85 131 41 18 -17 24 25 129 59 52 -16 52 5 132 53 25 -17 46 35 128 43 38 -16 26 55
130 32 18 -18 2 24 15 13 59 38 112 -84 131 22 44 -18 18 16 129 41 4 -17 45 56 132 35 3 -18 40 28 128 24 42 -17 20 45
130 12 23 -18 55 48 15 14 25 38 111 -83 131 2 59 -19 11 42 129 21 0 -18 39 18 132 15 32 -19 33 56 128 4 26 -18 14 6
129 51 13 -19 48 46 15 14 51 38 111 -82 130 41 59 -20 4 43 128 59 39 -19 32 14 131 54 49 -20 27 0 127 42 50 -19 6 59
129 28 46 -20 41 19 15 15 18 38 110 -81 130 19 45 -20 57 19 128 37 0 -20 24 43 131 32 54 -21 19 42 127 19 53 -19 59 23
129 5 1 -21 33 27 15 15 44 38 109 -81 129 56 15 -21 49 32 128 13 1 -21 16 47 131 9 46 -22 12 2 126 55 34 -20 51 20
128 39 57 -22 25 11 15 16 10 38 109 -80 129 31 27 -22 41 22 127 47 40 -22 8 26 130 45 21 -23 3 59 126 29 50 -21 42 50
128 13 31 -23 16 32 15 16 36 38 108 -79 129 5 18 -23 32 49 127 20 56 -22 59 39 130 19 39 -23 55 36 126 2 40 -22 33 54
127 45 40 -24 7 28 15 17 3 38 108 -78 128 37 48 -24 23 53 126 52 46 -23 50 28 129 52 37 -24 46 51 125 34 1 -23 24 30
127 16 23 -24 58 1 15 17 29 38 107 -77 128 8 52 -25 14 35 126 23 8 -24 40 52 129 24 13 -25 37 45 125 3 51 -24 14 41
126 45 37 -25 48 11 15 17 55 38 107 -76 127 38 29 -26 4 54 125 51 58 -25 30 51 128 54 23 -26 28 17 124 32 7 -25 4 24
126 13 18 -26 37 56 15 18 22 38 106 -75 127 6 35 -26 54 50 125 19 13 -26 20 25 128 23 6 -27 18 29 123 58 44 -25 53 41
125 39 23 -27 27 17 15 18 48 37 106 -74 126 33 7 -27 44 23 124 44 51 -27 9 34 127 50 16 -28 8 19 123 23 41 -26 42 30
125 3 48 -28 16 14 15 19 14 37 105 -73 125 58 1 -28 33 33 124 8 46 -27 58 16 127 15 52 -28 57 48 122 46 53 -27 30 52
124 26 28 -29 4 45 15 19 40 37 105 -73 125 21 13 -29 22 20 123 30 56 -28 46 33 126 39 48 -29 46 55 122 8 15 -28 18 44
123 47 21 -29 52 51 15 20 7 37 104 -72 124 42 38 -30 10 41 122 51 14 -29 34 21 126 2 0 -30 35 39 121 27 42 -29 6 7
123 6 19 -30 40 29 15 20 33 36 104 -71 124 2 12 -30 58 37 122 9 37 -30 21 42 125 22 24 -31 23 59 120 45 11 -29 52 59
122 23 19 -31 27 40 15 20 59 36 104 -70 123 19 49 -31 46 7 121 25 58 -31 8 32 124 40 55 -32 11 55 120 0 34 -30 39 19
121 38 14 -32 14 21 15 21 25 36 103 -69 122 35 24 -32 33 9 120 40 12 -31 54 52 123 57 26 -32 59 26 119 13 46 -31 25 5
120 50 57 -33 0 32 15 21 52 35 103 -68 121 48 50 -33 19 42 119 52 12 -32 40 39 123 11 53 -33 46 30 118 24 39 -32 10 16
120 1 23 -33 46 10 15 22 18 35 103 -67 121 0 0 -34 5 44 119 1 51 -33 25 51 122 24 7 -34 33 6 117 33 7 -32 54 48
119 9 22 -34 31 13 15 22 44 35 103 -66 120 8 48 -34 51 14 118 9 1 -34 10 27 121 34 2 -35 19 12 116 39 1 -33 38 40
118 14 47 -35 15 38 15 23 10 34 102 -65 119 15 4 -35 36 8 117 13 33 -34 54 22 120 41 30 -36 4 45 115 42 12 -34 21 48
117 17 29 -35 59 24 15 23 37 34 102 -64 118 18 40 -36 20 24 116 15 19 -35 37 34 119 46 22 -36 49 45 114 42 31 -35 4 9
116 17 18 -36 42 25 15 24 3 33 102 -63 117 19 27 -37 4 0 115 14 7 -36 20 0 118 48 29 -37 34 7 113 39 47 -35 45 39
115 14 3 -37 24 40 15 24 29 32 102 -62 116 17 13 -37 46 51 114 9 47 -37 1 36 117 47 41 -38 17 48 112 33 47 -36 26 13
114 7 31 -38 6 2 15 24 55 32 102 -61 115 11 47 -38 28 54 113 2 7 -37 42 16 116 43 47 -39 0 45 111 24 19 -37 5 46
Uncertainty in time = +/- 22 secs
Prediction of 2010 Apr 16.0
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