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Updated: 2011 Oct 13, 16:58 UT
Event Rank : 6
(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 26 UT, the 11 km diameter asteroid (5376) 1990 DD will occult a 10.4 mag star in the constellation Perseus for observers along a path across southern Australia, running from Horsham in Victoria to Karratha in Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 4.7 mag to 15.1 mag (the magnitude of the asteroid) for at most 1.8 seconds. Note the low elevation of this event.
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.
Occultation of TYC 2871-02426-1 by 5376 1990 DD on 2011 Oct 26
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
139 4 43 -41 0 0 14 8 29 3 22 -36 139 16 19 138 53 0 ... .. .. 134 6 48
139 19 7 -40 0 0 14 8 32 4 22 -38 139 30 24 139 7 43 ... .. .. 134 31 10
139 27 40 -39 0 0 14 8 37 5 21 -39 139 38 43 139 16 31 ... .. .. 134 47 18
139 30 46 -38 0 0 14 8 43 5 21 -40 139 41 38 139 19 49 ... .. .. 134 56 0
139 28 41 -37 0 0 14 8 50 6 22 -41 139 39 25 139 17 52 ... .. .. 134 57 46
139 21 37 -36 0 0 14 8 58 7 22 -41 139 32 15 139 10 52 ... .. .. 134 52 59
139 9 39 -35 0 0 14 9 7 8 22 -42 139 20 16 138 58 57 142 48 59 134 41 47
138 52 52 -34 0 0 14 9 17 9 22 -43 139 3 29 138 42 10 142 32 10 134 24 14
138 31 13 -33 0 0 14 9 29 10 22 -44 138 41 54 138 20 27 142 11 20 134 0 12
138 4 37 -32 0 0 14 9 42 11 23 -45 138 15 24 137 53 44 141 46 28 133 29 23
137 32 51 -31 0 0 14 9 56 11 23 -46 137 43 48 137 21 48 141 17 27 132 51 17
136 55 39 -30 0 0 14 10 11 12 23 -47 137 6 51 136 44 21 140 44 8 132 5 6
136 12 35 -29 0 0 14 10 28 13 24 -48 136 24 6 136 0 56 140 6 18 131 9 31
135 23 2 -28 0 0 14 10 47 13 25 -49 135 34 59 135 10 57 139 23 40 130 2 30
134 26 10 -27 0 0 14 11 7 14 25 -50 134 38 41 134 13 29 138 35 50 128 40 25
133 20 41 -26 0 0 14 11 30 15 26 -50 133 33 59 133 7 11 137 42 15 126 56 4
132 4 40 -25 0 0 14 11 55 15 27 -51 132 19 3 131 50 1 136 42 11 124 29 58
130 34 56 -24 0 0 14 12 24 15 28 -52 130 50 56 130 18 35 135 34 35 ... .. ..
128 45 39 -23 0 0 14 12 58 15 29 -52 129 4 16 128 26 26 134 17 59 ... .. ..
126 23 24 -22 0 0 14 13 39 15 30 -52 126 47 16 125 58 13 132 50 4 ... .. ..
125 0 0 -21 33 13 14 14 2 15 31 -52 -21 24 44 -21 41 47 -18 38 58 -25 10 19
124 0 0 -21 17 30 14 14 18 15 32 -52 -21 9 7 -21 25 56 -18 25 15 -24 50 41
123 0 0 -21 4 37 14 14 34 15 32 -52 -20 56 21 -21 12 59 -18 13 57 -24 34 49
122 0 0 -20 54 32 14 14 49 14 33 -51 -20 46 19 -21 2 49 -18 5 0 -24 22 33
121 0 0 -20 47 10 14 15 4 14 33 -51 -20 39 0 -20 55 24 -17 58 24 -24 13 45
120 0 0 -20 42 29 14 15 18 13 34 -50 -20 34 20 -20 50 42 -17 54 6 -24 8 21
119 0 0 -20 40 29 14 15 32 13 35 -50 -20 32 20 -20 48 42 -17 52 7 -24 6 19
118 0 0 -20 41 9 14 15 45 12 35 -49 -20 32 59 -20 49 24 -17 52 26 -24 7 38
117 0 0 -20 44 32 14 15 58 12 35 -49 -20 36 20 -20 52 49 -17 55 5 -24 12 21
116 0 0 -20 50 39 14 16 10 11 36 -48 -20 42 23 -20 59 0 -18 0 5 -24 20 34
115 0 0 -20 59 35 14 16 22 11 36 -47 -20 51 13 -21 8 1 -18 7 29 -24 32 24
114 0 0 -21 11 24 14 16 33 10 37 -47 -21 2 55 -21 19 57 -18 17 19 -24 48 2
113 0 0 -21 26 13 14 16 44 9 37 -46 -21 17 36 -21 34 55 -18 29 39 -25 7 43
112 0 0 -21 44 10 14 16 54 8 38 -45 -21 35 22 -21 53 3 -18 44 35 -25 31 49
Uncertainty in time = +/- 17 secs
Prediction of 2011 Oct 13.0
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