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Updated: 2008 MAY 13, 06:48 UT
Event Rank : 97
(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 2008 Jun 18 UT, the 117 km diameter asteroid (476) Hedwig will occult a 12.1 mag star in the constellation Hydra for observers along a path across Australia, from western Cape York parallel to the Queensland eastern coast to Port Maquarrie in New South Wales; and across the South Island of New Zealand from Haast to Palmerston.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.0 mag to 12.5 mag (the magnitude of the asteroid) for at most 18.0 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 20 27 - 4 0 0 12 45 55 61 214 -55 138 57 22 137 43 43 139 27 3 137 14 27
138 42 8 - 5 0 0 12 45 39 61 215 -56 139 19 12 138 5 16 139 49 0 137 35 54
139 4 25 - 6 0 0 12 45 22 62 217 -56 139 41 39 138 27 24 140 11 34 137 57 54
139 27 20 - 7 0 0 12 45 4 63 219 -57 140 4 44 138 50 8 140 34 48 138 20 31
139 50 53 - 8 0 0 12 44 47 63 220 -58 140 28 28 139 13 29 140 58 42 138 43 43
140 15 5 - 9 0 0 12 44 30 64 222 -59 140 52 53 139 37 29 141 23 17 139 7 34
140 39 58 -10 0 0 12 44 12 64 224 -60 141 18 0 140 2 9 141 48 35 139 32 3
141 5 33 -11 0 0 12 43 54 65 226 -60 141 43 50 140 27 30 142 14 37 139 57 13
141 31 52 -12 0 0 12 43 37 65 228 -61 142 10 25 140 53 34 142 41 25 140 23 4
141 58 57 -13 0 0 12 43 19 65 230 -62 142 37 46 141 20 21 143 9 0 140 49 39
142 26 49 -14 0 0 12 43 1 66 232 -63 143 5 56 141 47 55 143 37 26 141 16 58
142 55 29 -15 0 0 12 42 42 66 234 -63 143 34 57 142 16 16 144 6 42 141 45 4
143 25 1 -16 0 0 12 42 24 66 236 -64 144 4 50 142 45 27 144 36 52 142 13 59
143 55 26 -17 0 0 12 42 6 67 239 -65 144 35 37 143 15 30 145 7 58 142 43 45
Latitude Latitude Latitude Latitude
144 0 0 -17 8 52 12 42 3 67 239 -65 -15 50 25 -18 25 42 -14 46 25 -19 26 8
145 0 0 -19 1 40 12 41 28 67 244 -66 -17 46 14 -20 15 42 -16 44 47 -21 13 59
146 0 0 -20 48 15 12 40 55 67 248 -67 -19 35 32 -21 59 44 -18 36 23 -22 56 5
147 0 0 -22 29 7 12 40 23 66 252 -69 -21 18 51 -23 38 16 -20 21 47 -24 32 51
148 0 0 -24 4 41 12 39 53 66 255 -69 -22 56 39 -25 11 42 -22 1 28 -26 4 38
149 0 0 -25 35 18 12 39 24 66 259 -70 -24 29 21 -26 40 21 -23 35 53 -27 31 47
150 0 0 -27 1 20 12 38 56 65 262 -71 -25 57 17 -28 4 34 -25 5 24 -28 54 36
151 0 0 -28 23 5 12 38 30 65 264 -72 -27 20 47 -29 24 37 -26 30 22 -30 13 21
152 0 0 -29 40 49 12 38 4 64 267 -72 -28 40 9 -30 40 46 -27 51 5 -31 28 16
153 0 0 -30 54 46 12 37 40 63 269 -72 -29 55 38 -31 53 15 -29 7 50 -32 39 37
154 0 0 -32 5 11 12 37 17 62 271 -73 -31 7 28 -33 2 18 -30 20 51 -33 47 35
155 0 0 -33 12 16 12 36 55 62 272 -73 -32 15 53 -34 8 5 -31 30 22 -34 52 21
:
165 0 0 -41 55 22 12 33 56 53 279 -71 -41 8 49 -42 41 36 -40 31 20 -43 18 22
166 0 0 -42 35 43 12 33 41 53 279 -70 -41 49 53 -43 21 14 -41 13 0 -43 57 27
167 0 0 -43 14 17 12 33 28 52 279 -70 -42 29 9 -43 59 8 -41 52 49 -44 34 49
168 0 0 -43 51 10 12 33 14 51 279 -69 -43 6 41 -44 35 23 -42 30 53 -45 10 34
169 0 0 -44 26 26 12 33 1 50 279 -69 -43 42 35 -45 10 2 -43 7 17 -45 44 44
170 0 0 -45 0 10 12 32 49 49 279 -68 -44 16 53 -45 43 11 -43 42 5 -46 17 25
171 0 0 -45 32 24 12 32 37 49 279 -68 -44 49 41 -46 14 52 -44 15 20 -46 48 39
172 0 0 -46 3 13 12 32 25 48 279 -67 -45 21 3 -46 45 9 -44 47 8 -47 18 32
173 0 0 -46 32 41 12 32 14 47 278 -67 -45 51 1 -47 14 6 -45 17 31 -47 47 5
174 0 0 -47 0 49 12 32 3 47 278 -66 -46 19 39 -47 41 46 -45 46 32 -48 14 23
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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