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Updated: 2018 AUG 12, 18:07 UT
Event Rank : 99
(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 2018 Sep 29 UT, the 80.6 km diameter asteroid (568) Cheruskia will occult a 11.8 mag star in the constellation Andromeda for observers along a fairly broad path across eastern Australia from Rockhampton across south-eastern Queensland, western New South Wales, north-western Victoria and south-eastern South Australia to Keith.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.67 mag to 13.22 mag (the magnitude of the asteroid) for at most 8.6 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, astrometry for the asteroid kindly provided by Bill Owen, astrometry for the asteroid kindly provided by the IAU Minor Planet Center.
This work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
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 Alt
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 Crn
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
133 18 33 -44 0 0 14 9 37 14 14 -42 132 29 4 134 8 21 132 11 3 134 26 39 0.98
134 4 29 -43 0 0 14 9 32 15 14 -43 133 15 30 134 53 48 132 57 40 135 11 55 0.98
134 50 57 -42 0 0 14 9 27 16 13 -45 134 2 25 135 39 49 133 44 44 135 57 46 0.99
135 37 58 -41 0 0 14 9 22 17 12 -46 134 49 51 136 26 26 134 32 19 136 44 15 0.99
136 25 36 -40 0 0 14 9 16 18 12 -47 135 37 50 137 13 42 135 20 26 137 31 23 0.99
137 13 51 -39 0 0 14 9 10 19 11 -48 136 26 25 138 1 38 136 9 8 138 19 13 0.99
138 2 47 -38 0 0 14 9 3 20 11 -49 137 15 38 138 50 18 136 58 27 139 7 46 1.00
138 52 26 -37 0 0 14 8 56 22 10 -50 138 5 31 139 39 43 137 48 26 139 57 6 1.00
139 42 51 -36 0 0 14 8 48 23 9 -51 138 56 8 140 29 56 138 39 8 140 47 15 1.00
140 34 4 -35 0 0 14 8 41 24 8 -52 139 47 31 141 21 0 139 30 34 141 38 16 1.00
141 26 9 -34 0 0 14 8 32 25 8 -53 140 39 42 142 12 58 140 22 49 142 30 12 1.00
142 19 7 -33 0 0 14 8 24 26 7 -54 141 32 46 143 5 53 141 15 54 143 23 5 1.00
143 13 4 -32 0 0 14 8 14 27 6 -55 142 26 45 143 59 47 142 9 54 144 16 59 1.00
144 8 1 -31 0 0 14 8 5 28 5 -57 143 21 42 144 54 46 143 4 51 145 11 58 1.00
145 4 3 -30 0 0 14 7 55 29 5 -58 144 17 42 145 50 52 144 0 50 146 8 6 1.00
146 1 15 -29 0 0 14 7 44 30 4 -59 145 14 47 146 48 9 144 57 54 147 5 26 1.00
146 59 39 -28 0 0 14 7 34 31 3 -60 146 13 3 147 46 43 145 56 7 148 4 3 1.00
147 59 21 -27 0 0 14 7 22 32 2 -60 147 12 34 148 46 37 146 55 34 149 4 3 1.00
149 0 26 -26 0 0 14 7 10 33 1 -61 148 13 25 149 47 58 147 56 20 150 5 30 1.00
150 3 0 -25 0 0 14 6 58 34 360 -62 149 15 41 150 50 51 148 58 30 151 8 30 1.00
151 7 8 -24 0 0 14 6 45 35 359 -63 150 19 28 151 55 23 150 2 10 152 13 10 1.00
152 12 59 -23 0 0 14 6 32 36 358 -64 151 24 53 153 1 40 151 7 26 153 19 38 1.00
153 20 38 -22 0 0 14 6 18 37 357 -65 152 32 4 154 9 51 152 14 26 154 28 1 1.00
154 30 16 -21 0 0 14 6 3 38 355 -65 153 41 7 155 20 5 153 23 18 155 38 29 1.00
155 42 1 -20 0 0 14 5 48 39 354 -66 154 52 13 156 32 31 154 34 10 156 51 11 1.00
Uncertainty in time = +/- 3 secs
Prediction of 2018 Aug 12.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
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