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Updated: 2007 SEP 03, 06:29 UT
Event Rank : 32
(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 Oct 05 UT, the 45 km diameter asteroid (1254) Erfordia will occult a 10.9 mag star in the constellation Auriga for observers along a large uncertainty path across southern Western Australia, beginning near Denmark, central Australia and Queensland, leaving near Ayr.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.4 mag to 16.3 mag (the magnitude of the asteroid) for at most 8.9 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
114 2 36 -37 0 0 18 59 5 19 25 -33 114 36 13 113 29 14 116 58 45 111 12 47
115 25 28 -36 0 0 18 59 23 21 24 -33 115 59 13 114 51 58 118 22 34 112 35 7
116 49 46 -35 0 0 18 59 42 22 23 -32 117 23 44 116 16 4 119 48 13 113 58 36
118 15 43 -34 0 0 19 0 3 24 22 -32 118 49 58 117 41 45 121 15 55 115 23 22
119 43 33 -33 0 0 19 0 25 25 21 -31 120 18 10 119 9 14 122 45 58 116 49 39
121 13 32 -32 0 0 19 0 50 26 19 -30 121 48 37 120 38 47 124 18 42 118 17 40
122 45 59 -31 0 0 19 1 16 28 18 -30 123 21 39 122 10 42 125 54 33 119 47 41
124 21 16 -30 0 0 19 1 45 29 16 -29 124 57 38 123 45 19 127 33 57 121 19 57
125 59 48 -29 0 0 19 2 15 30 15 -28 126 37 1 125 23 4 129 17 32 122 54 51
127 42 8 -28 0 0 19 2 49 32 13 -27 128 20 23 127 4 26 131 6 0 124 32 44
129 28 54 -27 0 0 19 3 25 33 11 -25 130 8 25 128 50 0 133 0 19 126 14 7
131 20 55 -26 0 0 19 4 3 34 9 -24 132 1 59 130 40 34 135 1 44 127 59 33
133 19 15 -25 0 0 19 4 46 36 7 -23 134 2 15 132 37 5 137 11 59 129 49 47
135 25 18 -24 0 0 19 5 32 37 5 -21 136 10 47 134 40 52 139 33 33 131 45 42
136 0 0 -23 44 12 19 5 45 37 4 -20 -24 4 52 -23 23 42 -25 32 36 -21 59 57
137 0 0 -23 17 38 19 6 8 38 3 -19 -23 38 10 -22 57 15 -25 5 20 -21 34 0
138 0 0 -22 52 1 19 6 30 38 2 -19 -23 12 26 -22 31 45 -24 39 2 -21 9 0
139 0 0 -22 27 21 19 6 53 39 1 -18 -22 47 39 -22 7 13 -24 13 43 -20 44 55
140 0 0 -22 3 39 19 7 16 39 359 -17 -22 23 50 -21 43 37 -23 49 24 -20 21 46
141 0 0 -21 40 55 19 7 39 39 358 -16 -22 0 59 -21 21 0 -23 26 4 -19 59 34
142 0 0 -21 19 9 19 8 3 40 357 -15 -21 39 7 -20 59 20 -23 3 43 -19 38 20
143 0 0 -20 58 22 19 8 26 40 356 -14 -21 18 13 -20 38 39 -22 42 23 -19 18 2
144 0 0 -20 38 33 19 8 50 40 354 -13 -20 58 19 -20 18 56 -22 22 3 -18 58 42
145 0 0 -20 19 43 19 9 13 40 353 -12 -20 39 23 -20 0 11 -22 2 43 -18 40 19
146 0 0 -20 1 53 19 9 37 41 352 -11 -20 21 27 -19 42 26 -21 44 24 -18 22 54
147 0 0 -19 45 1 19 10 0 41 350 -10 -20 4 30 -19 25 39 -21 27 5 -18 6 26
148 0 0 -19 29 8 19 10 24 41 349 -9 -19 48 33 -19 9 51 -21 10 47 -17 50 57
149 0 0 -19 14 15 19 10 47 41 348 -8 -19 33 35 -18 55 2 -20 55 30 -17 36 25
150 0 0 -19 0 20 19 11 11 41 347 -7 -19 19 37 -18 41 12 -20 41 13 -17 22 52
151 0 0 -18 47 25 19 11 34 41 345 -6 -19 6 38 -18 28 21 -20 27 57 -17 10 16
152 0 0 -18 35 30 19 11 57 41 344 -5 -18 54 38 -18 16 28 -20 15 41 -16 58 38
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
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[Asteroid Occultation Results]
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