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Updated: 2007 JAN 11, 21:56 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 2007 Feb 08 UT, the 70 km diameter asteroid (746) Marlu will occult a 11.8 mag star in the constellation Virgo for observers along across north west Western Australia, beginning across Skark bay and ending near Onslow.
In the case of an occultation, the combined light of the asteroid and the star will drop by 4.0 mag to 15.7 mag (the magnitude of the asteroid) for at most 11.9 seconds.
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 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
116 2 43 -18 0 0 18 53 41 67 77 -42 115 40 53 116 24 30 114 57 54 117 7 0
115 47 56 -19 0 0 18 54 0 66 75 -41 115 25 57 116 9 52 114 42 40 116 52 40
115 32 35 -20 0 0 18 54 19 66 73 -41 115 10 26 115 54 40 114 26 49 116 37 48
115 16 38 -21 0 0 18 54 38 65 71 -40 114 54 18 115 38 54 114 10 20 116 22 22
115 0 4 -22 0 0 18 54 56 65 69 -40 114 37 33 115 22 31 113 53 13 116 6 21
114 42 52 -23 0 0 18 55 15 64 67 -39 114 20 9 115 5 31 113 35 25 115 49 43
114 25 1 -24 0 0 18 55 34 64 66 -38 114 2 5 114 47 53 113 16 56 115 32 29
114 6 29 -25 0 0 18 55 52 63 64 -38 113 43 19 114 29 34 112 57 44 115 14 36
113 47 14 -26 0 0 18 56 11 62 63 -37 113 23 50 114 10 33 112 37 46 114 56 2
113 27 14 -27 0 0 18 56 29 62 61 -37 113 3 35 113 50 48 112 17 1 114 36 47
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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