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Updated: 2018 Feb 27, 18:36 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 Apr 11 UT, the 119 km diameter asteroid (410) Chloris will occult a 12.0 mag star in the constellation Cancer for observers along a path across north-western West Australia and South Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.84 mag to 13.66 mag (the magnitude of the asteroid) for at most 20.1 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.
Occultation of 2UCAC 41710230 by 410 Chloris on 2018 Apr 11
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
144 39 58 -37 0 0 13 49 49 4 310 -61 143 35 43 145 44 51 143 8 51 146 12 21 0.10
143 9 31 -36 0 0 13 49 47 6 311 -61 142 6 55 144 12 42 141 40 44 144 39 27 0.12
141 42 8 -35 0 0 13 49 44 7 312 -62 140 41 2 142 43 44 140 15 28 143 9 49 0.13
140 17 31 -34 0 0 13 49 40 9 312 -62 139 17 47 141 17 41 138 52 47 141 43 9 0.14
138 55 25 -33 0 0 13 49 35 10 313 -62 137 56 58 139 54 17 137 32 29 140 19 11 0.14
137 35 39 -32 0 0 13 49 29 12 314 -63 136 38 22 138 33 18 136 14 22 138 57 41 0.15
136 18 0 -31 0 0 13 49 23 13 315 -63 135 21 48 137 14 33 134 58 14 137 38 26 0.15
135 2 18 -30 0 0 13 49 16 15 315 -63 134 7 5 135 57 49 133 43 56 136 21 16 0.15
133 48 23 -29 0 0 13 49 8 16 316 -63 132 54 5 134 42 57 132 31 19 135 6 0 0.15
132 36 7 -28 0 0 13 49 0 18 316 -63 131 42 40 133 29 48 131 20 15 133 52 28 0.15
131 25 21 -27 0 0 13 48 51 19 317 -62 130 32 41 132 18 14 130 10 35 132 40 33 0.16
130 15 58 -26 0 0 13 48 42 21 318 -62 129 24 2 131 8 6 129 2 14 131 30 6 0.16
129 7 52 -25 0 0 13 48 31 22 318 -62 128 16 35 129 59 18 127 55 4 130 21 0 0.16
128 0 55 -24 0 0 13 48 21 24 319 -61 127 10 16 128 51 43 126 48 59 129 13 8 0.16
126 55 2 -23 0 0 13 48 9 25 319 -61 126 4 57 127 45 14 125 43 55 128 6 25 0.16
125 50 7 -22 0 0 13 47 57 26 320 -60 125 0 33 126 39 47 124 39 44 127 0 43 0.16
124 46 5 -21 0 0 13 47 45 28 320 -60 123 57 0 125 35 15 123 36 23 125 55 59 0.16
123 42 51 -20 0 0 13 47 31 29 321 -59 122 54 12 124 31 34 122 33 46 124 52 6 0.16
122 40 20 -19 0 0 13 47 17 31 321 -58 121 52 5 123 28 38 121 31 48 123 48 59 0.16
121 38 27 -18 0 0 13 47 3 32 322 -58 120 50 34 122 26 23 120 30 27 122 46 34 0.16
120 37 9 -17 0 0 13 46 48 34 322 -57 119 49 36 121 24 44 119 29 36 121 44 47 0.16
119 36 20 -16 0 0 13 46 33 35 323 -56 118 49 5 120 23 38 118 29 12 120 43 32 0.16
Uncertainty in time = +/- 4 secs
Prediction of 2018 Feb 27.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
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[Asteroid Occultation Results]
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