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Updated: 2005 JUL 24, 01:45 UT
Event Rank : 99
(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 2005 Aug 21 UT, the 148 km diameter asteroid (51) Nemausa will occult a 11.1 mag star in the constellation Pisces for observers along a path across eastern New South Wales and Victoria, passing over Sydney, near Canberra and over south-eastern NSW and Gippsland.
In the case of an occultation, the combined light of the asteroid and the star will drop by only 0.9 mag to 11.6 mag (the magnitude of the asteroid) for at most 36.6 seconds. This event may be difficult to observe visually. In addition a full moon is only 25° away.
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 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
165 19 1 -11 17 10 14 2 45 54 63 -75 166 5 45 -11 20 39 164 31 54 -11 13 46 166 25 16 -11 22 8 164 11 59 -11 12 22
164 45 25 -12 39 5 14 3 21 53 61 -75 165 32 33 -12 42 33 163 57 54 -12 35 42 165 52 13 -12 44 2 163 37 48 -12 34 19
164 10 5 -14 1 44 14 3 56 52 60 -76 164 57 39 -14 5 11 163 22 6 -13 58 23 165 17 30 -14 6 40 163 1 49 -13 57 0
163 32 52 -15 25 12 14 4 31 51 59 -76 164 20 55 -15 28 38 162 44 22 -15 21 52 164 40 59 -15 30 6 162 23 52 -15 20 30
162 53 35 -16 49 34 14 5 7 49 58 -76 163 42 12 -16 52 58 162 4 30 -16 46 15 164 2 29 -16 54 26 161 43 45 -16 44 53
162 12 3 -18 14 54 14 5 42 48 57 -76 163 1 17 -18 18 17 161 22 19 -18 11 37 163 21 50 -18 19 44 161 1 17 -18 10 16
161 28 2 -19 41 19 14 6 17 47 56 -76 162 17 59 -19 44 40 160 37 34 -19 38 4 162 38 49 -19 46 6 160 16 13 -19 36 44
160 41 15 -21 8 55 14 6 53 46 56 -76 161 32 0 -21 12 14 159 49 59 -21 5 42 161 53 10 -21 13 40 159 28 17 -21 4 23
159 51 25 -22 37 49 14 7 28 44 55 -75 160 43 3 -22 41 6 158 59 13 -22 34 39 161 4 35 -22 42 30 158 37 6 -22 33 21
158 58 7 -24 8 9 14 8 3 43 55 -74 159 50 46 -24 11 23 158 4 52 -24 5 2 160 12 42 -24 12 46 157 42 18 -24 3 46
158 0 55 -25 40 4 14 8 39 41 54 -74 158 54 42 -25 43 15 157 6 27 -25 37 1 159 17 7 -25 44 37 156 43 23 -25 35 46
156 59 14 -27 13 45 14 9 14 40 54 -73 157 54 20 -27 16 51 156 3 25 -27 10 46 158 17 17 -27 18 12 155 39 44 -27 9 34
155 52 24 -28 49 23 14 9 49 38 54 -72 156 49 0 -28 52 25 154 55 0 -28 46 30 157 12 33 -28 53 44 154 30 38 -28 45 20
154 39 32 -30 27 13 14 10 24 37 54 -71 155 37 53 -30 30 9 153 40 18 -30 24 27 156 2 9 -30 31 26 153 15 8 -30 23 21
153 19 33 -32 7 33 14 11 0 35 54 -69 154 19 57 -32 10 21 152 18 9 -32 4 55 154 45 2 -32 11 35 151 52 2 -32 3 52
151 51 1 -33 50 41 14 11 35 33 54 -68 152 53 51 -33 53 20 150 47 1 -33 48 15 153 19 55 -33 54 30 150 19 46 -33 47 17
150 12 1 -35 37 5 14 12 10 31 54 -66 151 17 49 -35 39 31 149 4 51 -35 34 53 151 45 4 -35 40 37 148 36 12 -35 34 1
148 19 55 -37 27 17 14 12 46 29 55 -65 149 29 23 -37 29 26 147 8 47 -37 25 23 149 58 6 -37 30 25 146 38 23 -37 24 41
146 10 55 -39 21 59 14 13 21 26 56 -63 147 25 5 -39 23 45 144 54 39 -39 20 32 147 55 40 -39 24 35 144 21 56 -39 20 2
143 39 14 -41 22 14 14 13 56 24 57 -60 144 59 44 -41 23 26 142 15 58 -41 21 25 145 32 47 -41 24 4 141 40 5 -41 21 13
140 35 23 -43 29 31 14 14 32 21 59 -58 142 4 56 -43 29 52 139 1 49 -43 29 43 142 41 30 -43 30 10 138 21 8 -43 29 59
136 41 39 -45 46 25 14 15 7 17 61 -55 138 25 43 -45 45 18 134 50 49 -45 48 25 139 7 43 -45 45 4 134 1 51 -45 49 33
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