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Updated: 2009 AUG 20, 18:46 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 2009 Sep 22 UT, the 148 km diameter asteroid (283) Emma will occult a 11.3 mag star in the constellation Aries for observers along a broad path across the South Island of New Zealand from Oamaru to Haast, and across Australia from Brisbane to Darwin. (NB MP is Double)
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.9 mag to 13.0 mag (the magnitude of the asteroid) for at most 34.6 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
173 52 23 -49 0 0 16 6 37 12 344 -21 175 36 34 172 7 2 176 34 27 171 7 29
172 59 33 -48 0 0 16 6 46 13 344 -22 174 42 23 171 15 32 175 39 30 170 16 43
172 6 20 -47 0 0 16 6 56 14 345 -23 173 47 56 170 23 32 174 44 21 169 25 23
171 12 42 -46 0 0 16 7 7 16 346 -24 172 53 11 169 31 0 173 48 57 168 33 29
170 18 36 -45 0 0 16 7 19 17 346 -25 171 58 3 168 37 55 172 53 15 167 40 56
169 23 59 -44 0 0 16 7 32 18 347 -26 171 2 30 167 44 11 171 57 10 166 47 43
168 28 46 -43 0 0 16 7 46 19 348 -27 170 6 28 166 49 48 171 0 39 165 53 46
167 32 57 -42 0 0 16 8 0 20 349 -28 169 9 54 165 54 41 170 3 40 164 59 2
166 36 27 -41 0 0 16 8 16 21 349 -29 168 12 45 164 58 48 169 6 8 164 3 29
165 39 12 -40 0 0 16 8 32 22 350 -30 167 14 57 164 2 5 168 8 0 163 7 4
164 41 11 -39 0 0 16 8 50 23 351 -31 166 16 27 163 4 30 167 9 13 162 9 43
163 42 19 -38 0 0 16 9 8 24 352 -32 165 17 11 162 5 59 166 9 44 161 11 23
162 42 32 -37 0 0 16 9 27 25 353 -33 164 17 7 161 6 29 165 9 28 160 12 0
161 41 48 -36 0 0 16 9 48 27 353 -34 163 16 10 160 5 55 164 8 23 159 11 30
160 40 2 -35 0 0 16 10 9 28 354 -35 162 14 16 159 4 14 163 6 24 158 9 51
159 37 11 -34 0 0 16 10 31 29 355 -37 161 11 22 158 1 22 162 3 27 157 6 56
158 33 9 -33 0 0 16 10 54 30 356 -38 160 7 23 156 57 13 160 59 28 156 2 43
157 27 52 -32 0 0 16 11 19 31 357 -39 159 2 15 155 51 44 159 54 24 154 57 4
156 21 15 -31 0 0 16 11 44 32 358 -40 157 55 53 154 44 48 158 48 8 153 49 56
155 13 13 -30 0 0 16 12 10 33 359 -42 156 48 12 153 36 21 157 40 37 152 41 12
154 3 40 -29 0 0 16 12 38 34 0 -43 155 39 6 152 26 15 156 31 44 151 30 46
152 52 29 -28 0 0 16 13 7 35 1 -44 154 28 29 151 14 25 155 21 24 150 18 30
151 39 34 -27 0 0 16 13 36 36 3 -46 153 16 15 150 0 41 154 9 31 149 4 17
150 24 46 -26 0 0 16 14 7 37 4 -47 152 2 17 148 44 57 152 55 58 147 47 57
149 7 57 -25 0 0 16 14 40 38 5 -48 150 46 26 147 27 1 151 40 36 146 29 20
147 48 57 -24 0 0 16 15 13 38 7 -50 149 28 34 146 6 44 150 23 19 145 8 15
146 27 36 -23 0 0 16 15 48 39 8 -51 148 8 32 144 43 54 149 3 56 143 44 29
145 3 41 -22 0 0 16 16 24 40 10 -53 146 46 7 143 18 16 147 42 17 142 17 47
143 36 57 -21 0 0 16 17 2 41 11 -54 145 21 7 141 49 34 146 18 10 140 47 52
142 7 9 -20 0 0 16 17 41 42 13 -56 143 53 18 140 17 29 144 51 21 139 14 22
140 33 57 -19 0 0 16 18 22 42 15 -57 142 22 23 138 41 40 143 21 36 137 36 54
138 56 59 -18 0 0 16 19 4 43 17 -59 140 48 3 137 1 39 141 48 35 135 54 59
137 15 47 -17 0 0 16 19 49 43 19 -61 139 9 55 135 16 55 140 11 59 134 8 0
135 29 50 -16 0 0 16 20 35 44 21 -63 137 27 31 133 26 48 138 31 21 132 15 13
133 38 26 -15 0 0 16 21 23 44 23 -65 135 40 17 131 30 27 136 46 12 130 15 40
131 40 45 -14 0 0 16 22 14 44 25 -67 133 47 34 129 26 48 134 55 55 128 8 6
129 35 40 -13 0 0 16 23 8 44 28 -69 131 48 28 127 14 24 132 59 43 125 50 51
Latitude Latitude Latitude Latitude
128 0 0 -12 16 42 16 23 49 44 30 -70 -11 14 31 -13 20 10 -10 40 13 -13 56 20
127 0 0 -11 50 40 16 24 14 44 31 -71 -10 48 52 -12 53 44 -10 14 47 -13 29 39
126 0 0 -11 25 31 16 24 39 44 32 -72 -10 24 5 -12 28 11 - 9 50 12 -13 3 51
125 0 0 -11 1 13 16 25 4 44 33 -73 -10 0 9 -12 3 31 - 9 26 27 -12 38 58
Uncertainty in time = +/- 13 secs
Prediction of 2009 Aug 21.0
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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