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Updated: 2009 JUN 25, 15:29 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 2009 Aug 03 UT, the 175 km diameter asteroid (89) Julia will occult a 11.7 mag star in the constellation Andromeda for observers along a south-to-north path across Austrlia from south-west South Australia to north-east Northern Territory.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.3 mag to 10.3 mag (the magnitude of the asteroid) for at most 13.4 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
118 10 56 -48 0 0 17 47 51 13 34 -54 119 34 29 116 46 18 120 34 1 115 44 40
119 7 49 -47 0 0 17 47 54 14 33 -54 120 29 8 117 45 32 121 27 6 116 45 38
120 2 3 -46 0 0 17 47 56 15 32 -54 121 21 17 118 41 56 122 17 50 117 43 39
120 53 52 -45 0 0 17 47 59 17 32 -55 122 11 11 119 35 45 123 6 22 118 38 57
121 43 27 -44 0 0 17 48 2 18 31 -55 122 58 58 120 27 11 123 52 54 119 31 47
122 30 58 -43 0 0 17 48 5 19 31 -55 123 44 49 121 16 27 124 37 35 120 22 20
123 16 36 -42 0 0 17 48 8 20 30 -55 124 28 52 122 3 41 125 20 32 121 10 46
124 0 27 -41 0 0 17 48 12 21 30 -55 125 11 16 122 49 4 126 1 54 121 57 16
124 42 41 -40 0 0 17 48 15 22 29 -55 125 52 7 123 32 42 126 41 48 122 41 58
125 23 24 -39 0 0 17 48 19 24 29 -55 126 31 32 124 14 45 127 20 18 123 24 59
126 2 42 -38 0 0 17 48 23 25 28 -55 127 9 37 124 55 17 127 57 32 124 6 27
126 40 40 -37 0 0 17 48 27 26 28 -55 127 46 27 125 34 27 128 33 34 124 46 28
127 17 25 -36 0 0 17 48 31 27 28 -55 128 22 8 126 12 18 129 8 29 125 25 8
127 53 1 -35 0 0 17 48 36 28 27 -55 128 56 43 126 48 56 129 42 21 126 2 32
128 27 32 -34 0 0 17 48 40 29 27 -55 129 30 16 127 24 26 130 15 14 126 38 46
129 1 3 -33 0 0 17 48 45 30 27 -55 130 2 53 127 58 52 130 47 13 127 13 53
129 33 36 -32 0 0 17 48 50 31 26 -55 130 34 36 128 32 18 131 18 19 127 47 58
130 5 17 -31 0 0 17 48 55 32 26 -55 131 5 28 129 4 48 131 48 37 128 21 4
130 36 7 -30 0 0 17 49 0 34 26 -55 131 35 32 129 36 25 132 18 9 128 53 15
131 6 11 -29 0 0 17 49 5 35 26 -54 132 4 52 130 7 13 132 46 59 129 24 35
131 35 30 -28 0 0 17 49 10 36 25 -54 132 33 31 130 37 14 133 15 8 129 55 7
132 4 7 -27 0 0 17 49 16 37 25 -54 133 1 29 131 6 30 133 42 40 130 24 52
132 32 5 -26 0 0 17 49 21 38 25 -53 133 28 51 131 35 6 134 9 36 130 53 55
132 59 26 -25 0 0 17 49 27 39 25 -53 133 55 38 132 3 2 134 35 58 131 22 17
133 26 13 -24 0 0 17 49 33 40 25 -53 134 21 52 132 30 22 135 1 49 131 50 1
133 52 26 -23 0 0 17 49 39 41 24 -52 134 47 35 132 57 7 135 27 11 132 17 9
134 18 9 -22 0 0 17 49 45 42 24 -52 135 12 49 133 23 19 135 52 4 132 43 43
134 43 23 -21 0 0 17 49 51 43 24 -52 135 37 36 133 49 1 136 16 32 133 9 45
135 8 10 -20 0 0 17 49 57 44 24 -51 136 1 57 134 14 13 136 40 35 133 35 17
135 32 31 -19 0 0 17 50 4 45 24 -51 136 25 53 134 38 59 137 4 15 134 0 21
135 56 27 -18 0 0 17 50 10 47 24 -50 136 49 28 135 3 19 137 27 33 134 24 57
136 20 2 -17 0 0 17 50 17 48 24 -50 137 12 41 135 27 15 137 50 31 134 49 9
136 43 15 -16 0 0 17 50 24 49 24 -49 137 35 34 135 50 48 138 13 11 135 12 57
137 6 8 -15 0 0 17 50 31 50 23 -49 137 58 9 136 14 0 138 35 33 135 36 23
137 28 43 -14 0 0 17 50 38 51 23 -48 138 20 27 136 36 52 138 57 38 135 59 28
137 51 0 -13 0 0 17 50 45 52 23 -47 138 42 28 136 59 25 139 19 29 136 22 13
138 13 1 -12 0 0 17 50 52 53 23 -47 139 4 15 137 21 41 139 41 5 136 44 40
138 34 47 -11 0 0 17 50 59 54 23 -46 139 25 48 137 43 41 140 2 29 137 6 50
138 56 20 -10 0 0 17 51 7 55 23 -46 139 47 9 138 5 26 140 23 41 137 28 44
139 17 40 - 9 0 0 17 51 14 56 23 -45 140 8 17 138 26 57 140 44 42 137 50 23
Uncertainty in time = +/- 5 secs
Prediction of 2009 Jun 25.0
Use these links for further information:
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[Observing Details]
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