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Updated: 2009 JUN 25, 15:48 UT
Event Rank : 81
(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 06 UT, the 77 km diameter asteroid (61) Danae will occult a 11.4 mag star in the constellation Scorpius for observers along a south-to-north path beginning near Port Macquarie and passing near Brisbane and Rockhampton, before ending near Mackay.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.2 mag to 12.2 mag (the magnitude of the asteroid) for at most 8.1 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
145 26 34 - 9 0 0 11 16 39 55 184 -44 145 49 2 145 4 9 146 19 12 144 34 10
145 44 6 -10 0 0 11 16 29 56 184 -44 146 6 39 145 21 35 146 36 57 144 51 29
146 2 0 -11 0 0 11 16 19 57 185 -45 146 24 39 145 39 23 146 55 4 145 9 9
146 20 16 -12 0 0 11 16 8 58 185 -45 146 43 2 145 57 33 147 13 36 145 27 10
146 38 56 -13 0 0 11 15 58 59 186 -46 147 1 49 146 16 6 147 32 33 145 45 34
146 58 1 -14 0 0 11 15 47 60 186 -46 147 21 2 146 35 3 147 51 56 146 4 21
147 17 32 -15 0 0 11 15 36 61 187 -46 147 40 41 146 54 26 148 11 46 146 23 33
147 37 29 -16 0 0 11 15 25 62 187 -47 148 0 47 147 14 14 148 32 4 146 43 10
147 57 54 -17 0 0 11 15 14 63 188 -47 148 21 21 147 34 30 148 52 51 147 3 13
148 18 48 -18 0 0 11 15 3 64 189 -48 148 42 25 147 55 14 149 14 8 147 23 44
148 40 11 -19 0 0 11 14 52 65 190 -48 149 3 59 148 16 27 149 35 57 147 44 43
149 2 6 -20 0 0 11 14 41 66 191 -48 149 26 5 148 38 11 149 58 19 148 6 12
149 24 34 -21 0 0 11 14 29 67 192 -49 149 48 45 149 0 26 150 21 15 148 28 12
149 47 36 -22 0 0 11 14 18 68 193 -49 150 12 0 149 23 16 150 44 47 148 50 44
150 11 14 -23 0 0 11 14 6 69 194 -49 150 35 51 149 46 40 151 8 57 149 13 51
150 35 29 -24 0 0 11 13 55 69 195 -50 151 0 21 150 10 41 151 33 46 149 37 33
151 0 24 -25 0 0 11 13 43 70 197 -50 151 25 31 150 35 21 151 59 16 150 1 53
151 25 59 -26 0 0 11 13 31 71 199 -50 151 51 22 151 0 41 152 25 30 150 26 51
151 52 18 -27 0 0 11 13 19 72 200 -50 152 17 58 151 26 43 152 52 29 150 52 31
152 19 23 -28 0 0 11 13 7 73 202 -51 152 45 21 151 53 29 153 20 16 151 18 54
152 47 15 -29 0 0 11 12 55 73 205 -51 153 13 33 152 21 3 153 48 53 151 46 3
153 15 58 -30 0 0 11 12 43 74 207 -51 153 42 36 152 49 26 154 18 24 152 14 0
153 45 35 -31 0 0 11 12 30 75 210 -51 154 12 33 153 18 41 154 48 50 152 42 47
154 16 7 -32 0 0 11 12 18 75 213 -51 154 43 28 153 48 51 155 20 16 153 12 28
Latitude Latitude Latitude Latitude
155 0 0 -33 22 58 11 12 1 76 218 -52 -32 31 18 -34 14 18 -31 21 32 -35 22 38
Uncertainty in time = +/- 5 secs
Prediction of 2009 Jun 25.0
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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