|
|
Updated: 2008 OCT 30, 13:55 UT
Event Rank : 47
(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 Nov 04 UT, the 38 km diameter asteroid (339) Dorothea will occult a 8.8 mag star in the constellation Monoceros for observers along a narrow path across eastern Australia from Nelson Bay in New South Wales to Hervey Bay in Queensland. Brisbane is inside, and Sydney just outside, the one sigma limit.
In the case of an occultation, the combined light of the asteroid and the star will drop by 5.8 mag to 14.6 mag (the magnitude of the asteroid) for at most 8.7 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 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
151 23 57 -43 0 0 17 20 7 36 11 -12 151 9 45 151 38 7 150 30 49 152 16 56
151 30 9 -42 0 0 17 19 52 37 11 -13 151 16 12 151 44 7 150 37 53 152 22 18
151 36 5 -41 0 0 17 19 36 38 11 -14 151 22 20 151 49 49 150 44 37 152 27 25
151 41 45 -40 0 0 17 19 20 39 11 -14 151 28 12 151 55 17 150 51 3 152 32 19
151 47 9 -39 0 0 17 19 4 40 11 -15 151 33 48 152 0 29 150 57 11 152 37 0
151 52 19 -38 0 0 17 18 47 41 11 -15 151 39 9 152 5 28 151 3 2 152 41 28
151 57 15 -37 0 0 17 18 30 42 12 -16 151 44 16 152 10 14 151 8 38 152 45 45
152 1 58 -36 0 0 17 18 13 43 12 -16 151 49 9 152 14 47 151 13 59 152 49 51
152 6 29 -35 0 0 17 17 56 44 12 -17 151 53 50 152 19 9 151 19 6 152 53 47
152 10 49 -34 0 0 17 17 38 45 12 -17 151 58 18 152 23 19 151 23 59 152 57 32
152 14 56 -33 0 0 17 17 19 46 12 -18 152 2 34 152 27 18 151 28 39 153 1 8
152 18 53 -32 0 0 17 17 1 47 13 -19 152 6 40 152 31 7 151 33 7 153 4 34
152 22 40 -31 0 0 17 16 42 48 13 -19 152 10 34 152 34 45 151 37 22 153 7 52
152 26 16 -30 0 0 17 16 23 49 13 -20 152 14 17 152 38 14 151 41 26 153 11 0
152 29 43 -29 0 0 17 16 4 50 13 -20 152 17 51 152 41 34 151 45 19 153 14 1
152 33 0 -28 0 0 17 15 44 51 14 -21 152 21 15 152 44 44 151 49 1 153 16 53
152 36 7 -27 0 0 17 15 24 52 14 -21 152 24 29 152 47 45 151 52 32 153 19 37
152 39 6 -26 0 0 17 15 4 53 15 -22 152 27 33 152 50 38 151 55 53 153 22 13
152 41 55 -25 0 0 17 14 43 54 15 -22 152 30 28 152 53 22 151 59 4 153 24 41
152 44 36 -24 0 0 17 14 23 55 15 -23 152 33 14 152 55 57 152 2 5 153 27 2
152 47 8 -23 0 0 17 14 2 55 16 -24 152 35 51 152 58 24 152 4 56 153 29 15
152 49 31 -22 0 0 17 13 40 56 16 -24 152 38 20 153 0 43 152 7 37 153 31 21
152 51 46 -21 0 0 17 13 19 57 17 -25 152 40 39 153 2 53 152 10 9 153 33 19
152 53 52 -20 0 0 17 12 57 58 17 -25 152 42 49 153 4 55 152 12 31 153 35 9
Uncertainty in time = +/- 12 secs
[Prediction of 2008 Oct 30.0]
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
[Top of Page][Return to Home Page]