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Updated: 2008 JAN 17, 17:37 UT
Event Rank : 98
(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 Jan 23 UT, the 87 km diameter asteroid (424) Gratia will occult a 11.4 mag star in the constellation Cancer for observers along a wide path across the north island of New Zealand and later over northern Queensland, Northern Territory and the far northern Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.0 mag to 13.2 mag (the magnitude of the asteroid) for at most 7.6 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
179 32 52 -42 0 0 12 55 36 24 359 -28 -179 23 22 178 28 19 -178 37 55 177 41 20
178 32 1 -41 0 0 12 55 44 25 360 -29 179 35 34 177 27 40 -179 39 10 176 40 48
177 29 59 -40 0 0 12 55 52 26 1 -30 178 33 23 176 25 45 179 18 33 175 38 57
176 26 41 -39 0 0 12 56 1 27 2 -31 177 30 1 175 22 29 178 15 7 174 35 42
175 22 3 -38 0 0 12 56 11 28 3 -32 176 25 23 174 17 48 177 10 28 173 30 57
174 15 57 -37 0 0 12 56 21 29 4 -33 175 19 24 173 11 35 176 4 32 172 24 37
173 8 19 -36 0 0 12 56 31 30 5 -34 174 11 56 172 3 43 174 57 10 171 16 33
171 59 0 -35 0 0 12 56 42 31 6 -36 173 2 54 170 54 5 173 48 18 170 6 40
170 47 54 -34 0 0 12 56 53 32 8 -37 171 52 10 169 42 33 172 37 48 168 54 48
169 34 51 -33 0 0 12 57 4 33 9 -38 170 39 35 168 28 58 171 25 32 167 40 46
168 19 41 -32 0 0 12 57 17 34 10 -39 169 25 1 167 13 8 170 11 21 166 24 26
167 2 14 -31 0 0 12 57 29 34 12 -40 168 8 17 165 54 53 168 55 6 165 5 32
165 42 17 -30 0 0 12 57 42 35 13 -41 166 49 12 164 33 58 167 36 35 163 43 52
164 19 34 -29 0 0 12 57 56 36 15 -41 165 27 31 163 10 7 166 15 34 162 19 7
162 53 49 -28 0 0 12 58 11 37 17 -42 164 2 59 161 43 2 164 51 51 160 50 58
161 24 42 -27 0 0 12 58 26 37 19 -43 162 35 18 160 12 19 163 25 6 159 19 0
159 51 49 -26 0 0 12 58 41 38 20 -44 161 4 6 158 37 33 161 55 1 157 42 44
158 14 40 -25 0 0 12 58 58 38 22 -45 159 28 57 156 58 9 160 21 11 156 1 34
156 32 39 -24 0 0 12 59 15 38 24 -45 157 49 19 155 13 28 158 43 6 154 14 44
154 45 2 -23 0 0 12 59 33 39 27 -46 156 4 33 153 22 37 157 0 12 152 21 15
152 50 51 -22 0 0 12 59 52 39 29 -46 154 13 51 151 24 27 155 11 44 150 19 51
150 48 50 -21 0 0 13 0 12 39 31 -46 152 16 7 149 17 26 153 16 44 148 8 43
149 0 0 -20 10 2 13 0 30 38 33 -46 -19 28 40 -20 52 7 -18 59 17 -21 22 53
148 0 0 -19 43 55 13 0 40 38 34 -46 -19 2 50 -20 25 40 -18 33 40 -20 56 11
147 0 0 -19 18 47 13 0 49 38 35 -46 -18 38 0 -20 0 15 -18 9 2 -20 30 32
146 0 0 -18 54 40 13 0 59 38 37 -46 -18 14 9 -19 35 50 -17 45 22 -20 5 54
145 0 0 -18 31 31 13 1 8 38 38 -46 -17 51 16 -19 12 25 -17 22 40 -19 42 16
144 0 0 -18 9 22 13 1 18 37 39 -46 -17 29 22 -18 50 0 -17 0 56 -19 19 40
143 0 0 -17 48 11 13 1 27 37 40 -46 -17 8 25 -18 28 35 -16 40 9 -18 58 4
142 0 0 -17 27 59 13 1 36 37 41 -45 -16 48 26 -18 8 9 -16 20 19 -18 37 28
141 0 0 -17 8 46 13 1 45 36 42 -45 -16 29 25 -17 48 42 -16 1 27 -18 17 51
140 0 0 -16 50 30 13 1 54 36 42 -45 -16 11 21 -17 30 14 -15 43 31 -17 59 14
139 0 0 -16 33 12 13 2 3 36 43 -44 -15 54 14 -17 12 45 -15 26 32 -17 41 36
138 0 0 -16 16 52 13 2 12 35 44 -44 -15 38 4 -16 56 14 -15 10 29 -17 24 56
137 0 0 -16 1 28 13 2 20 35 45 -44 -15 22 51 -16 40 40 -14 55 22 -17 9 16
136 0 0 -15 47 3 13 2 29 34 46 -43 -15 8 33 -16 26 5 -14 41 11 -16 54 34
135 0 0 -15 33 34 13 2 37 34 47 -43 -14 55 13 -16 12 28 -14 27 56 -16 40 50
134 0 0 -15 21 1 13 2 45 33 48 -42 -14 42 48 -15 59 48 -14 15 36 -16 28 4
133 0 0 -15 9 26 13 2 53 33 48 -42 -14 31 19 -15 48 5 -14 4 12 -16 16 16
132 0 0 -14 58 47 13 3 1 32 49 -41 -14 20 47 -15 37 19 -13 53 44 -16 5 25
131 0 0 -14 49 4 13 3 9 31 50 -41 -14 11 10 -15 27 31 -13 44 11 -15 55 33
130 0 0 -14 40 18 13 3 16 31 50 -40 -14 2 28 -15 18 40 -13 35 33 -15 46 37
129 0 0 -14 32 28 13 3 24 30 51 -39 -13 54 43 -15 10 45 -13 27 50 -15 38 40
128 0 0 -14 25 34 13 3 31 29 52 -39 -13 47 53 -15 3 48 -13 21 3 -15 31 39
127 0 0 -14 19 37 13 3 38 29 52 -38 -13 41 58 -14 57 47 -13 15 11 -15 25 36
126 0 0 -14 14 36 13 3 45 28 53 -37 -13 37 0 -14 52 43 -13 10 14 -15 20 30
125 0 0 -14 10 31 13 3 52 27 53 -37 -13 32 56 -14 48 36 -13 6 12 -15 16 22
124 0 0 -14 7 22 13 3 59 27 54 -36 -13 29 49 -14 45 26 -13 3 5 -15 13 11
123 0 0 -14 5 10 13 4 5 26 54 -35 -13 27 37 -14 43 13 -13 0 54 -15 10 57
122 0 0 -14 3 54 13 4 12 25 55 -35 -13 26 21 -14 41 57 -12 59 38 -15 9 41
121 0 0 -14 3 34 13 4 18 24 55 -34 -13 26 1 -14 41 38 -12 59 17 -15 9 23
120 0 0 -14 4 11 13 4 24 24 56 -33 -13 26 37 -14 42 17 -12 59 52 -15 10 2
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
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[Report Form]
[Asteroid Occultation Results]
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