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Updated: 2011 JUL 21, 22:34 UT
Event Rank : 69
(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 Aug 22 UT, the 70 km diameter asteroid (1085) Amaryllis will occult a 11.5 mag star in the constellation Sagittarius for observers along a path beginning in Queensland and passing near Longreach. In NSW the path passes near Newcastle and Sydney. Then in South Island New Zealand near Wanaka and Dunedin.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.2 mag to 14.6 mag (the magnitude of the asteroid) for at most 20.3 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.
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
138 50 10 -10 0 0 12 24 52 66 246 -55 138 28 19 139 12 5 137 51 22 139 49 31
139 8 33 -11 0 0 12 25 27 66 248 -55 138 46 33 139 30 38 138 9 19 140 8 23
139 27 45 -12 0 0 12 26 2 66 250 -56 139 5 34 139 50 1 138 28 2 140 28 4
139 47 48 -13 0 0 12 26 38 66 253 -56 139 25 25 140 10 16 138 47 34 140 48 39
140 8 44 -14 0 0 12 27 14 65 255 -57 139 46 9 140 31 24 139 7 57 141 10 10
140 30 36 -15 0 0 12 27 49 65 257 -57 140 7 47 140 53 30 139 29 13 141 32 40
140 53 27 -16 0 0 12 28 25 65 259 -58 140 30 24 141 16 36 139 51 26 141 56 12
141 17 21 -17 0 0 12 29 1 64 261 -58 140 54 2 141 40 46 140 14 38 142 20 49
141 42 21 -18 0 0 12 29 37 64 263 -59 141 18 45 142 6 3 140 38 54 142 46 35
142 8 30 -19 0 0 12 30 14 64 265 -59 141 44 37 142 32 30 141 4 16 143 13 35
142 35 54 -20 0 0 12 30 50 63 267 -60 142 11 41 143 0 13 141 30 48 143 41 52
143 4 35 -21 0 0 12 31 27 62 269 -60 142 40 2 143 29 16 141 58 35 144 11 31
143 34 40 -22 0 0 12 32 3 62 271 -60 143 9 45 143 59 44 142 27 41 144 42 38
Latitude Latitude Latitude Latitude
144 0 0 -22 48 23 12 32 33 61 272 -61 -23 35 23 -22 0 32 -24 53 26 -20 37 2
145 0 0 -24 35 56 12 33 39 60 274 -61 -25 20 20 -23 50 48 -26 34 15 -22 32 15
146 0 0 -26 14 38 12 34 39 59 276 -62 -26 56 48 -25 31 50 -28 7 7 -24 17 31
147 0 0 -27 45 36 12 35 36 57 278 -62 -28 25 49 -27 4 50 -29 32 59 -25 54 11
148 0 0 -29 9 47 12 36 28 56 279 -62 -29 48 16 -28 30 48 -30 52 39 -27 23 21
149 0 0 -30 27 54 12 37 17 55 280 -62 -31 4 52 -29 50 30 -32 6 47 -28 45 52
150 0 0 -31 40 37 12 38 2 54 281 -62 -32 16 14 -31 4 37 -33 15 55 -30 2 30
151 0 0 -32 48 28 12 38 45 53 282 -62 -33 22 51 -32 13 44 -34 20 33 -31 13 51
152 0 0 -33 51 55 12 39 25 51 282 -62 -34 25 12 -33 18 19 -35 21 5 -32 20 27
153 0 0 -34 51 21 12 40 3 50 282 -62 -35 23 38 -34 18 47 -36 17 53 -33 22 44
154 0 0 -35 47 7 12 40 38 49 283 -62 -36 18 29 -35 15 29 -37 11 14 -34 21 5
155 0 0 -36 39 31 12 41 12 48 283 -62 -37 10 3 -36 8 45 -38 1 26 -35 15 51
156 0 0 -37 28 49 12 41 44 47 283 -61 -37 58 35 -36 58 50 -38 48 43 -36 7 19
157 0 0 -38 15 15 12 42 14 46 283 -61 -38 44 19 -37 45 59 -39 33 17 -36 55 44
158 0 0 -38 59 1 12 42 43 45 282 -61 -39 27 26 -38 30 25 -40 15 20 -37 41 19
159 0 0 -39 40 19 12 43 10 44 282 -61 -40 8 8 -39 12 19 -40 55 1 -38 24 18
160 0 0 -40 19 17 12 43 36 43 282 -60 -40 46 33 -39 51 51 -41 32 31 -39 4 50
161 0 0 -40 56 5 12 44 1 42 282 -60 -41 22 50 -40 29 11 -42 7 57 -39 43 5
162 0 0 -41 30 51 12 44 25 41 281 -60 -41 57 7 -41 4 26 -42 41 27 -40 19 11
163 0 0 -42 3 42 12 44 47 40 281 -59 -42 29 32 -41 37 45 -43 13 7 -40 53 17
164 0 0 -42 34 45 12 45 9 39 280 -59 -43 0 9 -42 9 13 -43 43 3 -41 25 29
165 0 0 -43 4 5 12 45 30 38 280 -59 -43 29 6 -42 38 56 -44 11 21 -41 55 54
166 0 0 -43 31 47 12 45 50 38 279 -58 -43 56 26 -43 7 0 -44 38 6 -42 24 37
167 0 0 -43 57 57 12 46 9 37 279 -58 -44 22 16 -43 33 31 -45 3 22 -42 51 43
168 0 0 -44 22 39 12 46 27 36 278 -57 -44 46 39 -43 58 32 -45 27 13 -43 17 17
169 0 0 -44 45 57 12 46 45 35 278 -57 -45 9 39 -44 22 8 -45 49 44 -43 41 25
170 0 0 -45 7 54 12 47 2 34 277 -57 -45 31 20 -44 44 22 -46 10 57 -44 4 8
171 0 0 -45 28 35 12 47 18 33 277 -56 -45 51 46 -45 5 19 -46 30 57 -44 25 32
172 0 0 -45 48 2 12 47 34 33 276 -56 -46 10 58 -45 25 0 -46 49 45 -44 45 39
173 0 0 -46 6 18 12 47 49 32 275 -56 -46 29 1 -45 43 30 -47 7 25 -45 4 32
174 0 0 -46 23 26 12 48 4 31 275 -55 -46 45 56 -46 0 51 -47 24 0 -45 22 15
175 0 0 -46 39 28 12 48 18 30 274 -55 -47 1 46 -46 17 4 -47 39 30 -45 38 49
176 0 0 -46 54 26 12 48 31 30 274 -54 -47 16 33 -46 32 14 -47 53 59 -45 54 18
177 0 0 -47 8 22 12 48 44 29 273 -54 -47 30 20 -46 46 20 -48 7 29 -46 8 42
178 0 0 -47 21 19 12 48 57 28 272 -54 -47 43 7 -46 59 27 -48 20 0 -46 22 5
179 0 0 -47 33 18 12 49 9 27 272 -53 -47 54 57 -47 11 34 -48 31 36 -46 34 28
180 0 0 -47 44 20 12 49 21 27 271 -53 -48 5 51 -47 22 44 -48 42 16 -46 45 52
Uncertainty in time = +/- 18 secs
Prediction of 2011 Jul 22.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
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[Asteroid Occultation Results]
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