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Updated: 2007 APR 06, 20:56 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 2007 Apr 21 UT, the 157 km diameter asteroid (139) Juewa will occult a 11.2 mag star in the constellation Scorpius for observers along a wide path from northern Queensland to south-eastern South Australia, passing directly over Cooktown and Broken Hill and just east of Adelaide.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.3 mag to 12.2 mag (the magnitude of the asteroid) for at most 27.7 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
145 41 31 -10 0 0 17 48 40 63 178 -38 144 57 34 146 25 23 144 26 45 146 56 3
145 30 34 -11 0 0 17 48 57 64 177 -38 144 46 28 146 14 36 144 15 33 146 45 22
145 19 28 -12 0 0 17 49 15 65 177 -38 144 35 12 146 3 39 144 4 9 146 34 32
145 8 11 -13 0 0 17 49 33 66 177 -38 144 23 44 145 52 33 143 52 34 146 23 34
144 56 44 -14 0 0 17 49 51 67 176 -39 144 12 5 145 41 18 143 40 47 146 12 27
144 45 6 -15 0 0 17 50 9 68 176 -39 144 0 15 145 29 53 143 28 47 146 1 10
144 33 17 -16 0 0 17 50 28 69 176 -39 143 48 12 145 18 17 143 16 35 145 49 44
144 21 17 -17 0 0 17 50 46 70 175 -39 143 35 58 145 6 32 143 4 10 145 38 9
144 9 5 -18 0 0 17 51 5 71 174 -39 143 23 30 144 54 35 142 51 32 145 26 23
143 56 42 -19 0 0 17 51 23 72 174 -39 143 10 49 144 42 28 142 38 39 145 14 27
143 44 5 -20 0 0 17 51 42 73 173 -40 142 57 55 144 30 9 142 25 33 145 2 21
143 31 16 -21 0 0 17 52 1 74 172 -40 142 44 47 144 17 39 142 12 11 144 50 3
143 18 13 -22 0 0 17 52 20 75 171 -40 142 31 25 144 4 56 141 58 35 144 37 34
143 4 57 -23 0 0 17 52 39 76 170 -40 142 17 47 143 52 1 141 44 42 144 24 54
142 51 26 -24 0 0 17 52 59 77 169 -40 142 3 54 143 38 52 141 30 34 144 12 0
142 37 41 -25 0 0 17 53 18 77 168 -40 141 49 45 143 25 30 141 16 8 143 58 55
142 23 40 -26 0 0 17 53 37 78 166 -40 141 35 19 143 11 54 141 1 24 143 45 35
142 9 23 -27 0 0 17 53 57 79 164 -40 141 20 36 142 58 2 140 46 22 143 32 2
141 54 49 -28 0 0 17 54 16 80 162 -40 141 5 34 142 43 56 140 31 1 143 18 15
141 39 57 -29 0 0 17 54 36 81 159 -40 140 50 13 142 29 34 140 15 20 143 4 13
141 24 48 -30 0 0 17 54 55 82 156 -40 140 34 33 142 14 54 139 59 18 142 49 55
141 9 19 -31 0 0 17 55 15 83 151 -40 140 18 32 141 59 58 139 42 54 142 35 20
140 53 30 -32 0 0 17 55 35 83 146 -40 140 2 9 141 44 42 139 26 7 142 20 28
140 37 20 -33 0 0 17 55 55 84 139 -40 139 45 23 141 29 8 139 8 56 142 5 19
140 20 48 -34 0 0 17 56 14 84 130 -40 139 28 14 141 13 13 138 51 20 141 49 50
140 3 53 -35 0 0 17 56 34 85 119 -40 139 10 39 140 56 57 138 33 17 141 34 1
139 46 33 -36 0 0 17 56 54 85 107 -40 138 52 38 140 40 19 138 14 47 141 17 52
139 28 48 -37 0 0 17 57 14 85 93 -39 138 34 9 140 23 17 137 55 46 141 1 20
139 10 36 -38 0 0 17 57 34 85 81 -39 138 15 10 140 5 50 137 36 15 140 44 25
138 51 54 -39 0 0 17 57 54 84 70 -39 137 55 40 139 47 57 137 16 11 140 27 5
138 32 42 -40 0 0 17 58 14 84 61 -39 137 35 37 139 29 36 136 55 32 140 9 19
138 12 58 -41 0 0 17 58 33 83 54 -39 137 14 59 139 10 45 136 34 15 139 51 5
137 52 40 -42 0 0 17 58 53 82 48 -39 136 53 44 138 51 23 136 12 20 139 32 22
137 31 45 -43 0 0 17 59 13 82 44 -39 136 31 49 138 31 27 135 49 43 139 13 7
137 10 11 -44 0 0 17 59 33 81 41 -38 136 9 11 138 10 55 135 26 20 138 53 19
136 47 55 -45 0 0 17 59 53 80 38 -38 135 45 49 137 49 46 135 2 11 138 32 55
Use these links for further information:
[Planetary Occultations]
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