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Updated: 2009 JUL 16, 01:56 UT
Event Rank : 62
(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 23 UT, the 48 km diameter asteroid (573) Recha will occult a 9.2 mag star in the constellation Sagittarius for observers along a path across South Island New Zealand in evening twilight centred from Christchurch to just north of Westport.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.2 mag to 14.4 mag (the magnitude of the asteroid) for at most 8.2 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, 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
174 59 40 -49 49 58 6 31 26 55 76 -10 174 35 45 -49 52 55 175 23 27 -49 46 57 173 48 30 -49 58 29 176 9 44 -49 40 51
174 36 8 -48 39 29 6 31 48 55 77 -10 174 12 46 -48 42 22 174 59 23 -48 36 32 173 26 38 -48 47 49 175 44 36 -48 30 33
174 11 57 -47 29 9 6 32 11 55 79 -9 173 49 6 -47 31 58 174 34 41 -47 26 16 173 3 58 -47 37 19 175 18 56 -47 20 25
173 47 7 -46 18 57 6 32 34 55 81 -9 173 24 45 -46 21 43 174 9 23 -46 16 7 172 40 34 -46 26 56 174 52 44 -46 10 24
173 21 40 -45 8 50 6 32 56 55 83 -9 172 59 44 -45 11 32 173 43 30 -45 6 4 172 16 26 -45 16 38 174 26 0 -45 0 29
172 55 36 -43 58 46 6 33 19 55 85 -8 172 34 5 -44 1 25 173 17 2 -43 56 4 171 51 35 -44 6 23 173 58 44 -43 50 36
172 28 55 -42 48 43 6 33 42 55 87 -8 172 7 47 -42 51 18 172 49 58 -42 46 5 171 26 3 -42 56 9 173 30 57 -42 40 45
172 1 38 -41 38 39 6 34 5 55 89 -7 171 40 50 -41 41 9 172 22 20 -41 36 5 170 59 48 -41 45 53 173 2 38 -41 30 52
171 33 43 -40 28 31 6 34 27 55 91 -7 171 13 15 -40 30 57 171 54 6 -40 26 0 170 32 53 -40 35 34 172 33 45 -40 20 56
171 5 11 -39 18 16 6 34 50 54 93 -6 170 45 1 -39 20 39 171 25 15 -39 15 50 170 5 15 -39 25 7 172 4 20 -39 10 53
170 36 0 -38 7 53 6 35 13 54 95 -6 170 16 7 -38 10 12 170 55 47 -38 5 31 169 36 54 -38 14 32 171 34 19 -38 0 42
170 6 10 -36 57 19 6 35 35 53 97 -5 169 46 33 -36 59 34 170 25 42 -36 55 1 169 7 51 -37 3 46 171 3 43 -36 50 21
169 35 39 -35 46 32 6 35 58 53 98 -5 169 16 16 -35 48 42 169 54 56 -35 44 18 168 38 3 -35 52 46 170 32 30 -35 39 46
169 4 26 -34 35 28 6 36 21 52 100 -4 168 45 16 -34 37 34 169 23 30 -34 33 19 168 7 29 -34 41 29 170 0 38 -34 28 56
168 32 28 -33 24 6 6 36 43 52 102 -4 168 13 31 -33 26 7 168 51 20 -33 22 1 167 36 8 -33 29 54 169 28 5 -33 17 47
167 59 45 -32 12 21 6 37 6 51 103 -3 167 40 59 -32 14 18 168 18 26 -32 10 21 167 3 58 -32 17 55 168 54 50 -32 6 16
167 26 14 -31 0 12 6 37 29 51 105 -3 167 7 38 -31 2 4 167 44 45 -30 58 17 166 30 56 -31 5 32 168 20 49 -30 54 21
166 51 51 -29 47 35 6 37 52 50 106 -2 166 33 24 -29 49 22 167 10 13 -29 45 45 165 57 0 -29 52 39 167 46 0 -29 41 59
166 16 35 -28 34 26 6 38 14 49 108 -1 165 58 15 -28 36 7 166 34 49 -28 32 42 165 22 6 -28 39 15 167 10 20 -28 29 6
165 40 20 -27 20 42 6 38 37 48 109 -1 165 22 8 -27 22 18 165 58 28 -27 19 3 164 46 12 -27 25 14 166 33 46 -27 15 38
Uncertainty in time = +/- 8 secs
Prediction of 2009 Jul 9.0
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