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Updated: 2014 Sep 19, 12:30 UT
Event Rank : 44
(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 2014 Oct 31 UT, the 70 km diameter asteroid (756) Lilliana will occult a 12.1 mag star in the constellation Pisces for observers along a somewhat uncertain path across south-eastern Queensland, eastern New South Wales and Victoria.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.0 mag to 15.1 mag (the magnitude of the asteroid) for at most 4.3 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.
Occultation of 2UCAC 34953125 by 756 Lilliana on 2014 Oct 31
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
138 50 18 -45 0 0 14 40 59 33 338 -31 138 3 23 139 37 34 135 47 21 141 58 45
139 37 14 -44 0 0 14 40 53 34 337 -32 138 50 46 140 24 4 136 36 3 142 44 0
140 24 58 -43 0 0 14 40 46 35 336 -33 139 38 53 141 11 25 137 25 22 143 30 13
141 13 31 -42 0 0 14 40 39 35 335 -34 140 27 47 141 59 37 138 15 19 144 17 27
142 2 55 -41 0 0 14 40 32 36 334 -35 141 17 29 142 48 43 139 5 57 145 5 43
142 53 13 -40 0 0 14 40 24 37 332 -36 142 8 3 143 38 46 139 57 18 145 55 5
143 44 27 -39 0 0 14 40 17 37 331 -36 142 59 30 144 29 48 140 49 26 146 45 33
144 36 41 -38 0 0 14 40 9 38 330 -37 143 51 53 145 21 52 141 42 22 147 37 12
145 29 56 -37 0 0 14 40 1 38 328 -38 144 45 17 146 15 1 142 36 11 148 30 5
146 24 17 -36 0 0 14 39 53 39 327 -39 145 39 42 147 9 18 143 30 54 149 24 15
147 19 47 -35 0 0 14 39 45 39 326 -40 146 35 14 148 4 47 144 26 36 150 19 46
148 16 31 -34 0 0 14 39 37 39 324 -41 147 31 57 149 1 32 145 23 20 151 16 42
149 14 31 -33 0 0 14 39 28 40 323 -41 148 29 53 149 59 37 146 21 10 152 15 9
150 13 54 -32 0 0 14 39 20 40 321 -42 149 29 9 150 59 9 147 20 11 153 15 11
151 14 45 -31 0 0 14 39 11 40 319 -43 150 29 49 152 0 11 148 20 27 154 16 56
152 17 8 -30 0 0 14 39 2 41 318 -43 151 31 59 153 2 50 149 22 3 155 20 30
153 21 12 -29 0 0 14 38 52 41 316 -44 152 35 45 154 7 13 150 25 5 156 26 1
154 27 3 -28 0 0 14 38 43 41 315 -44 153 41 14 155 13 28 151 29 39 157 33 37
155 34 49 -27 0 0 14 38 34 41 313 -45 154 48 34 156 21 42 152 35 52 158 43 29
156 44 41 -26 0 0 14 38 24 41 311 -45 155 57 54 157 32 7 153 43 52 159 55 50
157 56 47 -25 0 0 14 38 14 40 309 -46 157 9 23 158 44 54 154 53 47 161 10 51
Uncertainty in time = +/- 7 secs
Prediction of 2014 Sep 19.0
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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