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Updated: 2008 MAR 31, 03:09 UT
Event Rank : 83
(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 2008 Apr 29 UT, the 96 km diameter asteroid (773) Irmintraud will occult a 11.6 mag star in the constellation Corona Australis for observers along a path across Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.3 mag to 13.7 mag (the magnitude of the asteroid) for at most 20.6 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 38 10 -18 16 56 15 16 23 50 140 -70 151 8 44 -18 28 20 150 7 31 -18 5 16 151 46 31 -18 42 7 149 29 22 -17 50 26
150 18 40 -19 37 57 15 16 52 51 139 -70 150 49 23 -19 49 17 149 47 53 -19 26 22 151 27 20 -20 2 59 149 9 35 -19 11 38
149 57 53 -20 57 47 15 17 22 52 137 -70 150 28 45 -21 9 4 149 26 57 -20 46 15 151 6 55 -21 22 42 148 48 27 -20 31 36
149 35 48 -22 16 31 15 17 51 53 136 -70 150 6 51 -22 27 46 149 4 41 -22 5 2 150 45 15 -22 41 22 148 25 59 -21 50 25
149 12 23 -23 34 13 15 18 20 54 135 -70 149 43 38 -23 45 26 148 41 4 -23 22 44 150 22 18 -23 59 1 148 2 8 -23 8 10
148 47 38 -24 50 56 15 18 50 54 133 -69 149 19 6 -25 2 9 148 16 6 -24 39 28 149 58 3 -25 15 44 147 36 54 -24 24 53
148 21 29 -26 6 44 15 19 19 55 132 -69 148 53 12 -26 17 58 147 49 43 -25 55 15 149 32 27 -26 31 34 147 10 15 -25 40 39
147 53 56 -27 21 39 15 19 49 55 130 -69 148 25 54 -27 32 56 147 21 54 -27 10 9 149 5 29 -27 46 34 146 42 7 -26 55 31
147 24 54 -28 35 46 15 20 18 56 129 -68 147 57 9 -28 47 4 146 52 36 -28 24 12 148 37 5 -29 0 46 146 12 29 -28 9 32
146 54 20 -29 49 4 15 20 48 57 127 -68 147 26 53 -30 0 27 146 21 45 -29 37 27 148 7 12 -30 14 14 145 41 17 -29 22 42
146 22 12 -31 1 38 15 21 17 57 126 -67 146 55 4 -31 13 5 145 49 17 -30 49 56 147 35 46 -31 26 57 145 8 27 -30 35 6
145 48 23 -32 13 28 15 21 47 57 124 -67 146 21 36 -32 25 1 145 15 10 -32 1 41 147 2 44 -32 39 0 144 33 55 -31 46 44
145 12 51 -33 24 37 15 22 16 58 123 -66 145 46 25 -33 36 16 144 39 16 -33 12 43 146 28 0 -33 50 23 143 57 36 -32 57 38
144 35 30 -34 35 4 15 22 45 58 121 -65 145 9 25 -34 46 51 144 1 33 -34 23 3 145 51 29 -35 1 7 143 19 26 -34 7 49
143 56 13 -35 44 52 15 23 15 58 119 -65 144 30 32 -35 56 47 143 21 53 -35 32 43 145 13 6 -36 11 13 142 39 18 -35 17 18
143 14 55 -36 54 2 15 23 44 58 118 -64 143 49 39 -37 6 6 142 40 11 -36 41 43 144 32 43 -37 20 43 141 57 7 -36 26 6
142 31 28 -38 2 32 15 24 14 58 116 -63 143 6 37 -38 14 47 141 56 19 -37 50 3 143 50 14 -38 29 37 141 12 44 -37 34 14
141 45 45 -39 10 25 15 24 43 58 114 -63 142 21 21 -39 22 51 141 10 9 -38 57 44 143 5 32 -39 37 55 140 26 3 -38 41 40
140 57 36 -40 17 39 15 25 13 58 113 -62 141 33 41 -40 30 17 140 21 34 -40 4 46 142 18 27 -40 45 37 139 36 54 -39 48 26
140 6 54 -41 24 15 15 25 42 58 111 -61 140 43 27 -41 37 6 139 30 23 -41 11 8 141 28 50 -41 52 42 138 45 10 -40 54 31
139 13 27 -42 30 11 15 26 12 58 110 -61 139 50 30 -42 43 17 138 36 27 -42 16 49 140 36 31 -42 59 12 137 50 38 -41 59 53
138 17 5 -43 35 26 15 26 41 58 108 -60 138 54 38 -43 48 49 137 39 35 -43 21 48 139 41 18 -44 5 3 136 53 10 -43 4 32
137 17 34 -44 40 0 15 27 10 58 107 -59 137 55 39 -44 53 40 136 39 33 -44 26 4 138 42 59 -45 10 16 135 52 31 -44 8 26
Uncertainty in time = +/- 13 secs
[Prediction of 2008 Mar 31.0]
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