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Updated: 2013 OCT 02, 04:09 UT
Event Rank : 74
(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 2013 Nov 17 UT, the 78 km diameter asteroid (980) Anacostia will occult a 12.9 mag star in the constellation Cancer for observers along a path across Australia beginning in northern WA. The path moves south-east through central Australia, and into Victoria near Melbourne.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.1 mag to 13.5 mag (the magnitude of the asteroid) for at most 6.6 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, 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
147 6 28 -48 0 0 18 1 5 27 29 -4 146 16 57 147 55 28 145 0 38 149 9 2
146 52 59 -47 0 0 18 0 58 28 29 -4 146 4 16 147 41 12 144 49 11 148 53 36
146 38 12 -46 0 0 18 0 51 28 30 -5 145 50 13 147 25 42 144 36 17 148 37 0
146 22 9 -45 0 0 18 0 44 29 30 -6 145 34 51 147 8 59 144 21 58 148 19 17
146 4 54 -44 0 0 18 0 36 30 31 -7 145 18 13 146 51 6 144 6 18 148 0 29
145 46 27 -43 0 0 18 0 29 31 32 -7 145 0 20 146 32 5 143 49 18 147 40 37
145 26 51 -42 0 0 18 0 21 31 32 -8 144 41 16 146 11 58 143 31 2 147 19 42
145 6 6 -41 0 0 18 0 13 32 33 -9 144 21 0 145 50 44 143 11 31 146 57 45
144 44 14 -40 0 0 18 0 5 33 34 -10 143 59 34 145 28 26 142 50 45 146 34 48
144 21 16 -39 0 0 17 59 56 33 35 -11 143 36 59 145 5 5 142 28 46 146 10 51
143 57 11 -38 0 0 17 59 48 34 35 -11 143 13 16 144 40 39 142 5 34 145 45 53
143 32 0 -37 0 0 17 59 39 34 36 -12 142 48 24 144 15 10 141 41 10 145 19 56
143 5 44 -36 0 0 17 59 30 35 37 -13 142 22 23 143 48 37 141 15 34 144 52 58
142 38 21 -35 0 0 17 59 20 36 38 -14 141 55 14 143 21 0 140 48 45 144 24 59
142 9 51 -34 0 0 17 59 11 36 39 -15 141 26 55 142 52 18 140 20 43 143 56 0
141 40 13 -33 0 0 17 59 2 37 40 -16 140 57 26 142 22 31 139 51 27 143 25 57
141 9 26 -32 0 0 17 58 52 37 41 -17 140 26 46 141 51 37 139 20 56 142 54 52
140 37 29 -31 0 0 17 58 42 37 42 -18 139 54 53 141 19 35 138 49 8 142 22 42
140 4 19 -30 0 0 17 58 32 38 43 -19 139 21 45 140 46 23 138 16 2 141 49 25
139 29 55 -29 0 0 17 58 21 38 44 -20 138 47 21 140 12 0 137 41 35 141 15 1
138 54 15 -28 0 0 17 58 11 39 46 -21 138 11 37 139 36 22 137 5 45 140 39 26
138 17 16 -27 0 0 17 58 0 39 47 -22 137 34 32 138 59 28 136 28 28 140 2 38
137 38 54 -26 0 0 17 57 49 39 48 -23 136 56 1 138 21 14 135 49 42 139 24 35
136 59 7 -25 0 0 17 57 38 39 49 -24 136 16 2 137 41 38 135 9 23 138 45 13
136 17 50 -24 0 0 17 57 27 39 51 -25 135 34 30 137 0 35 134 27 25 138 4 28
135 34 59 -23 0 0 17 57 16 39 52 -27 134 51 21 136 18 1 133 43 44 137 22 18
134 50 29 -22 0 0 17 57 4 39 53 -28 134 6 28 135 33 51 132 58 14 136 38 37
134 4 14 -21 0 0 17 56 52 39 55 -29 133 19 47 134 48 1 132 10 49 135 53 20
133 16 7 -20 0 0 17 56 40 39 56 -30 132 31 10 134 0 22 131 21 20 135 6 21
132 26 2 -19 0 0 17 56 28 39 57 -31 131 40 28 133 10 50 130 29 39 134 17 34
131 33 48 -18 0 0 17 56 16 39 59 -33 130 47 34 132 19 15 129 35 36 133 26 52
130 39 18 -17 0 0 17 56 3 39 60 -34 129 52 16 131 25 28 128 38 58 132 34 7
129 42 18 -16 0 0 17 55 50 38 61 -36 128 54 21 130 29 19 127 39 33 131 39 8
128 42 36 -15 0 0 17 55 37 38 63 -37 127 53 37 129 30 35 126 37 2 130 41 45
127 39 56 -14 0 0 17 55 24 37 64 -38 126 49 44 128 29 2 125 31 7 129 41 44
126 34 0 -13 0 0 17 55 11 37 65 -40 125 42 23 127 24 23 124 21 23 128 38 52
125 24 24 -12 0 0 17 54 57 36 67 -41 124 31 10 126 16 18 123 7 22 127 32 49
124 10 42 -11 0 0 17 54 43 35 68 -43 123 15 32 125 4 21 121 48 25 126 23 15
122 52 19 -10 0 0 17 54 29 34 69 -45 121 54 52 123 48 2 120 23 46 125 9 45
121 28 33 - 9 0 0 17 54 15 33 70 -46 120 28 20 122 26 44 118 52 23 123 51 45
Uncertainty in time = +/- 5 secs
Prediction of 2013 Oct 2.0
Use these links for further information:
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[Observing Details]
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