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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 the time for your location)
On 2004 Feb 22 UT, the 41 km diameter asteroid (1191) Alfaterna will occult a 10.6 mag star in the constellation Orion for observers along a path across Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.5 mag to 16.1 mag (the magnitude of the asteroid) for at most 2.7 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Ron Stone, 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
... .. .. -63 0 0 .. .. .. .. .. .. ... .. .. ... .. .. ... .. .. 150 1 44
... .. .. -62 0 0 .. .. .. .. .. .. ... .. .. 151 8 39 ... .. .. 145 46 26
148 55 52 -61 0 0 13 26 58 2 291 -18 151 26 59 146 50 1 ... .. .. 142 44 49
145 28 47 -60 0 0 13 27 0 4 294 -19 147 19 13 143 49 33 153 10 40 140 23 30
142 54 47 -59 0 0 13 27 3 6 296 -19 144 26 5 141 30 14 148 44 58 138 28 59
140 52 48 -58 0 0 13 27 6 7 297 -20 142 12 26 139 37 50 145 47 48 136 54 3
139 13 7 -57 0 0 13 27 10 9 299 -20 140 24 42 138 5 1 143 33 22 135 34 22
137 50 12 -56 0 0 13 27 14 10 300 -21 138 55 51 136 47 19 141 46 2 134 26 57
136 40 35 -55 0 0 13 27 18 11 301 -22 137 41 38 135 41 50 140 18 6 133 29 46
135 41 53 -54 0 0 13 27 23 12 301 -22 136 39 15 134 46 28 139 5 5 132 41 15
134 52 22 -53 0 0 13 27 27 13 302 -23 135 46 43 133 59 42 138 4 2 132 0 16
134 10 45 -52 0 0 13 27 32 14 302 -24 135 2 35 133 20 24 137 12 56 131 25 52
133 36 2 -51 0 0 13 27 37 14 303 -24 134 25 45 132 47 40 136 30 18 130 57 19
133 7 27 -50 0 0 13 27 43 15 303 -25 133 55 21 132 20 46 135 55 1 130 34 3
132 44 21 -49 0 0 13 27 48 16 303 -26 133 30 42 131 59 8 135 26 13 130 15 34
132 26 14 -48 0 0 13 27 54 17 303 -26 133 11 16 131 42 17 135 3 13 130 1 28
132 12 42 -47 0 0 13 28 0 17 303 -27 132 56 34 131 29 50 134 45 29 129 51 25
132 3 24 -46 0 0 13 28 6 18 303 -28 132 46 16 131 21 28 134 32 35 129 45 8
131 58 2 -45 0 0 13 28 12 18 302 -29 132 40 3 131 16 55 134 24 9 129 42 24
131 56 23 -44 0 0 13 28 18 19 302 -30 132 37 40 131 15 58 134 19 53 129 43 0
131 58 16 -43 0 0 13 28 25 20 302 -30 132 38 56 131 18 26 134 19 35 129 46 47
132 3 31 -42 0 0 13 28 31 20 301 -31 132 43 41 131 24 11 134 23 3 129 53 38
132 12 1 -41 0 0 13 28 38 20 301 -32 132 51 47 131 33 5 134 30 8 130 3 27
132 23 42 -40 0 0 13 28 45 21 300 -33 133 3 9 131 45 4 134 40 43 130 16 8
132 38 28 -39 0 0 13 28 53 21 300 -34 133 17 42 132 0 4 134 54 46 130 31 39
132 56 19 -38 0 0 13 29 0 21 299 -35 133 35 25 132 18 2 135 12 14 130 49 57
133 17 13 -37 0 0 13 29 8 22 299 -36 133 56 18 132 38 58 135 33 5 131 11 1
133 41 11 -36 0 0 13 29 15 22 298 -37 134 20 20 133 2 54 135 57 23 131 34 53
134 8 17 -35 0 0 13 29 23 22 297 -38 134 47 37 133 29 51 136 25 12 132 1 34
134 38 35 -34 0 0 13 29 31 22 296 -39 135 18 11 133 59 53 136 56 37 132 31 8
135 12 11 -33 0 0 13 29 40 22 296 -40 135 52 12 134 33 8 137 31 49 133 3 39
135 49 15 -32 0 0 13 29 48 22 295 -41 136 29 49 135 9 42 138 11 0 133 39 14
136 29 59 -31 0 0 13 29 57 22 294 -43 137 11 15 135 49 48 138 54 27 134 18 2
137 14 37 -30 0 0 13 30 6 21 293 -44 137 56 47 136 33 38 139 42 34 135 0 16
138 3 31 -29 0 0 13 30 14 21 292 -45 138 46 48 137 21 32 140 35 49 135 46 8
138 57 7 -28 0 0 13 30 24 21 291 -46 139 41 47 138 13 52 141 34 53 136 35 57
139 55 57 -27 0 0 13 30 33 20 290 -48 140 42 23 139 11 9 142 40 41 137 30 8
141 0 49 -26 0 0 13 30 43 20 289 -49 141 49 28 140 14 2 143 54 32 138 29 9
Latitude Latitude Latitude Latitude
142 0 0 -25 10 9 13 30 51 19 289 -50 -25 51 8 -24 30 45 -27 36 18 -23 2 18
143 0 0 -24 23 54 13 30 59 18 288 -51 -25 3 15 -23 45 56 -26 43 36 -22 20 25
144 0 0 -23 41 32 13 31 6 18 287 -52 -24 19 30 -23 4 49 -25 55 50 -21 41 50
145 0 0 -23 2 45 13 31 13 17 286 -53 -23 39 32 -22 27 6 -25 12 28 -21 6 20
146 0 0 -22 27 16 13 31 19 16 286 -54 -23 3 2 -21 52 34 -24 33 3 -20 33 43
147 0 0 -21 54 54 13 31 25 15 285 -55 -22 29 46 -21 21 1 -23 57 18 -20 3 52
148 0 0 -21 25 27 13 31 30 15 285 -56 -21 59 32 -20 52 17 -23 24 55 -19 36 37
149 0 0 -20 58 46 13 31 36 14 284 -57 -21 32 11 -20 26 13 -22 55 41 -19 11 52
150 0 0 -20 34 44 13 31 40 13 284 -58 -21 7 33 -20 2 44 -22 29 25 -18 49 32
151 0 0 -20 13 13 13 31 45 12 283 -58 -20 45 32 -19 41 42 -22 5 59 -18 29 31
152 0 0 -19 54 9 13 31 49 11 283 -59 -20 26 1 -19 23 3 -21 45 15 -18 11 46
153 0 0 -19 37 27 13 31 53 10 282 -59 -20 8 55 -19 6 42 -21 27 7 -17 56 11
154 0 0 -19 23 2 13 31 56 10 282 -60 -19 54 11 -18 52 36 -21 11 29 -17 42 44
155 0 0 -19 10 51 13 31 59 9 281 -60 -19 41 43 -18 40 41 -20 58 16 -17 31 22
156 0 0 -19 0 52 13 32 2 8 281 -60 -19 31 30 -18 30 54 -20 47 26 -17 22 4
157 0 0 -18 53 1 13 32 4 7 281 -61 -19 23 28 -18 23 14 -20 38 54 -17 14 46
158 0 0 -18 47 17 13 32 6 6 280 -61 -19 17 36 -18 17 38 -20 32 39 -17 9 27
159 0 0 -18 43 39 13 32 8 5 280 -61 -19 13 51 -18 14 5 -20 28 38 -17 6 6
160 0 0 -18 42 5 13 32 10 4 280 -61 -19 12 13 -18 12 34 -20 26 50 -17 4 42
161 0 0 -18 42 34 13 32 11 3 279 -61 -19 12 41 -18 13 5 -20 27 15 -17 5 15
162 0 0 -18 45 6 13 32 12 2 279 -61 -19 15 14 -18 15 36 -20 29 51 -17 7 44
163 0 0 -18 49 41 13 32 12 1 279 -61 -19 19 53 -18 20 8 -20 34 40 -17 12 9
164 0 0 -18 56 19 13 32 13 0 278 -61 -19 26 37 -18 26 40 -20 41 40 -17 18 30
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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