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Updated: 2007 JUL 18, 03:23 UT
Event Rank : 8
(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 09 UT, the 18 km diameter asteroid (3713) Pieters will occult a 9.6 mag star in the constellation Sagittarius for observers along a narrow high uncertainty path beginning in Queensland with the centre line north of Mackay. The path then moves south-westerly passing near Emerald and Charleville and then into New South Wales passing near Bourke and Ivanhoe. Then into Victoria passing near St Arnaud and Warrnambool. The area of uncertainty at this point extends from near Mt Gambier in the west to Melbourne in the east.
In the case of an occultation, the combined light of the asteroid and the star will drop by 6.3 mag to 15.9 mag (the magnitude of the asteroid) for at most 4.0 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 Limit1 Path Limit2 Error Limit1 Error Limit2
E. Longitude Latitude U.T. Alt Az Alt
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
150 58 21 -16 42 53 12 32 17 62 255 -68 151 3 52 -16 43 52 150 52 51 -16 41 53 152 38 48 -17 0 12 149 19 42 -16 24 22
150 26 24 -18 0 37 12 32 49 62 257 -68 150 31 57 -18 1 37 150 20 52 -17 59 37 152 7 24 -18 18 10 148 47 13 -17 41 54
149 55 8 -19 18 6 12 33 21 63 260 -68 150 0 42 -19 19 6 149 49 34 -19 17 5 151 36 45 -19 35 52 148 15 20 -18 59 9
149 24 29 -20 35 20 12 33 54 64 262 -67 149 30 6 -20 36 22 149 18 53 -20 34 18 151 6 48 -20 53 20 147 44 1 -20 16 10
148 54 27 -21 52 24 12 34 26 64 265 -67 149 0 6 -21 53 26 148 48 48 -21 51 21 150 37 32 -22 10 37 147 13 14 -21 33 1
148 24 59 -23 9 19 12 34 58 64 267 -66 148 30 41 -23 10 22 148 19 17 -23 8 16 150 8 54 -23 27 46 146 42 56 -22 49 42
147 56 3 -24 26 9 12 35 31 65 270 -65 148 1 48 -24 27 13 147 50 19 -24 25 5 149 40 55 -24 44 49 146 13 7 -24 6 19
147 27 39 -25 42 56 12 36 3 65 273 -65 147 33 27 -25 44 0 147 21 51 -25 41 51 149 13 32 -26 1 49 145 43 45 -25 22 51
146 59 45 -26 59 42 12 36 35 65 276 -64 147 5 37 -27 0 47 146 53 54 -26 58 36 148 46 43 -27 18 50 145 14 47 -26 39 23
146 32 20 -28 16 30 12 37 7 65 279 -63 146 38 16 -28 17 36 146 26 25 -28 15 24 148 20 30 -28 35 52 144 46 14 -27 55 57
146 5 23 -29 33 23 12 37 40 65 282 -63 146 11 23 -29 34 30 145 59 24 -29 32 16 147 54 50 -29 52 59 144 18 3 -29 12 35
145 38 53 -30 50 23 12 38 12 65 285 -62 145 44 58 -30 51 31 145 32 49 -30 49 15 147 29 44 -31 10 14 143 50 13 -30 29 19
145 12 50 -32 7 33 12 38 44 65 288 -61 145 18 59 -32 8 41 145 6 41 -32 6 24 147 5 10 -32 27 38 143 22 43 -31 46 13
144 47 12 -33 24 55 12 39 17 65 291 -60 144 53 27 -33 26 4 144 40 58 -33 23 45 146 41 10 -33 45 16 142 55 33 -33 3 19
144 22 1 -34 42 32 12 39 49 65 294 -59 144 28 21 -34 43 42 144 15 41 -34 41 21 146 17 43 -35 3 9 142 28 42 -34 20 39
143 57 14 -36 0 27 12 40 21 64 297 -58 144 3 40 -36 1 38 143 50 48 -35 59 15 145 54 49 -36 21 20 142 2 8 -35 38 17
143 32 53 -37 18 43 12 40 53 64 300 -58 143 39 26 -37 19 55 143 26 21 -37 17 30 145 32 30 -37 39 53 141 35 52 -36 56 14
143 8 57 -38 37 22 12 41 26 63 302 -57 143 15 37 -38 38 35 143 2 18 -38 36 9 145 10 45 -38 58 49 141 9 51 -38 14 35
142 45 27 -39 56 28 12 41 58 63 305 -56 142 52 15 -39 57 43 142 38 40 -39 55 14 144 49 37 -40 18 13 140 44 7 -39 33 21
142 22 24 -41 16 4 12 42 30 62 307 -55 142 29 20 -41 17 20 142 15 29 -41 14 49 144 29 7 -41 38 8 140 18 39 -40 52 37
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