|
|
Updated: 2007 JUL 21, 21:39 UT
Event Rank : 17
(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 2007 Aug 22 UT, the 13 km diameter asteroid (1803) Zwicky will occult a 10.4 mag star in the constellation Ara for observers along a path beginning near Streaky Bay in South Australia. Moving north-easterly the path then moves into Queensland passing near Julia Creek and ending near Cooktown.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.1 mag to 15.5 mag (the magnitude of the asteroid) for at most 0.7 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
163 22 10 9 0 0 13 3 44 1 223 -69 163 27 17 163 17 2 164 7 12 ... .. ..
162 27 12 8 0 0 13 3 44 2 223 -70 162 32 15 162 22 8 163 11 41 ... .. ..
161 33 31 7 0 0 13 3 43 4 223 -71 161 38 32 161 28 32 162 17 30 160 49 52
160 41 4 6 0 0 13 3 43 5 223 -72 160 46 1 160 36 7 161 24 33 159 57 52
159 49 43 5 0 0 13 3 42 6 223 -73 159 54 37 159 44 49 160 32 47 159 6 57
158 59 26 4 0 0 13 3 41 7 222 -73 159 4 18 158 54 35 159 42 6 158 17 3
158 10 9 3 0 0 13 3 40 9 222 -74 158 14 58 158 5 20 158 52 27 157 28 6
157 21 47 2 0 0 13 3 38 10 222 -74 157 26 34 157 17 0 158 3 45 156 40 3
156 34 17 1 0 0 13 3 37 11 222 -75 156 39 2 156 29 32 157 15 57 155 52 51
155 47 36 0 0 0 13 3 35 13 222 -75 155 52 19 155 42 53 156 28 59 155 6 26
155 1 40 - 1 0 0 13 3 34 14 222 -75 155 6 21 154 56 59 155 42 49 154 20 44
Latitude Latitude Latitude Latitude
154 0 0 - 2 22 4 13 3 31 16 223 -76 - 2 28 19 - 2 15 49 - 3 17 7 - 1 27 32
153 0 0 - 3 43 30 13 3 28 17 223 -76 - 3 49 50 - 3 37 10 - 4 39 16 - 2 48 15
152 0 0 - 5 6 27 13 3 24 19 223 -76 - 5 12 52 - 5 0 2 - 6 2 57 - 4 10 30
151 0 0 - 6 30 50 13 3 21 21 223 -75 - 6 37 20 - 6 24 20 - 7 28 4 - 5 34 11
150 0 0 - 7 56 35 13 3 17 22 223 -75 - 8 3 10 - 7 50 1 - 8 54 33 - 6 59 14
149 0 0 - 9 23 37 13 3 12 24 223 -74 - 9 30 17 - 9 16 58 -10 22 17 - 8 25 34
148 0 0 -10 51 49 13 3 7 26 224 -73 -10 58 33 -10 45 5 -11 51 11 - 9 53 5
147 0 0 -12 21 4 13 3 2 28 224 -72 -12 27 53 -12 14 15 -13 21 6 -11 21 40
146 0 0 -13 51 14 13 2 57 29 224 -71 -13 58 8 -13 44 21 -14 51 57 -12 51 13
145 0 0 -15 22 12 13 2 51 31 225 -70 -15 29 10 -15 15 15 -16 23 32 -14 21 34
144 0 0 -16 53 48 13 2 45 33 225 -69 -17 0 50 -16 46 47 -17 55 45 -15 52 35
143 0 0 -18 25 54 13 2 39 35 226 -68 -18 32 59 -18 18 48 -19 28 24 -17 24 7
142 0 0 -19 58 18 13 2 32 36 227 -66 -20 5 27 -19 51 9 -21 1 20 -18 56 0
141 0 0 -21 30 50 13 2 25 38 227 -65 -21 38 3 -21 23 38 -22 34 22 -20 28 4
140 0 0 -23 3 20 13 2 18 40 228 -64 -23 10 36 -22 56 5 -24 7 18 -22 0 9
139 0 0 -24 35 37 13 2 10 42 229 -62 -24 42 55 -24 28 19 -25 39 58 -23 32 3
138 0 0 -26 7 29 13 2 3 43 230 -61 -26 14 49 -26 0 9 -27 12 9 -25 3 36
137 0 0 -27 38 45 13 1 55 45 231 -59 -27 46 8 -27 31 24 -28 43 42 -26 34 37
136 0 0 -29 9 15 13 1 47 47 232 -58 -29 16 39 -29 1 52 -30 14 23 -28 4 54
135 0 0 -30 38 47 13 1 39 48 233 -56 -30 46 12 -30 31 23 -31 44 4 -29 34 18
134 0 0 -32 7 11 13 1 30 50 235 -55 -32 14 36 -31 59 47 -33 12 33 -31 2 38
133 0 0 -33 34 18 13 1 22 51 236 -53 -33 41 43 -33 26 53 -34 39 40 -32 29 44
132 0 0 -34 59 58 13 1 14 53 238 -52 -35 7 23 -34 52 34 -36 5 17 -33 55 27
131 0 0 -36 24 3 13 1 5 54 239 -50 -36 31 27 -36 16 39 -37 29 14 -35 19 39
130 0 0 -37 46 25 13 0 57 56 241 -49 -37 53 48 -37 39 3 -38 51 25 -36 42 12
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
[Top of Page][Return to Home Page]