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Updated: 2017 Dec 15, 16:50 UT
Event Rank : 84
(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 Jan 01 UT, the 52 km diameter asteroid (1113) Katja will occult a 12.2 mag star in the constellation Auriga for observers along a somewhat uncertain path across Northern Territory and central and south-western West Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.34 mag to 13.20 mag (the magnitude of the asteroid) for at most 4.9 seconds. Note nearly full moon nearby.
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 45795367 by 1113 Katja on 2018 Jan 1
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
116 22 12 -37 0 0 13 27 37 11 16 -18 115 55 39 116 48 51 115 29 56 117 14 52 0.85
116 59 2 -36 0 0 13 27 34 12 16 -19 116 32 40 117 25 30 116 7 8 117 51 20 0.86
117 36 30 -35 0 0 13 27 30 13 15 -20 117 10 18 118 2 48 116 44 56 118 28 28 0.87
118 14 36 -34 0 0 13 27 27 14 15 -21 117 48 33 118 40 46 117 23 20 119 6 17 0.87
118 53 23 -33 0 0 13 27 23 15 15 -22 118 27 28 119 19 25 118 2 23 119 44 49 0.87
119 32 52 -32 0 0 13 27 19 16 14 -23 119 7 3 119 58 47 118 42 5 120 24 5 0.88
120 13 4 -31 0 0 13 27 14 17 14 -25 119 47 21 120 38 53 119 22 28 121 4 6 0.88
120 54 1 -30 0 0 13 27 9 18 13 -26 120 28 23 121 19 46 120 3 34 121 44 55 0.88
121 35 46 -29 0 0 13 27 4 19 13 -27 121 10 11 122 1 27 120 45 26 122 26 33 0.89
122 18 19 -28 0 0 13 26 58 21 12 -28 121 52 47 122 43 59 121 28 4 123 9 3 0.89
123 1 44 -27 0 0 13 26 52 22 12 -29 122 36 13 123 27 23 122 11 32 123 52 26 0.89
123 46 3 -26 0 0 13 26 46 23 11 -30 123 20 32 124 11 42 122 55 51 124 36 45 0.89
124 31 18 -25 0 0 13 26 39 24 11 -31 124 5 46 124 56 58 123 41 4 125 22 2 0.89
125 17 32 -24 0 0 13 26 33 25 10 -33 124 51 57 125 43 14 124 27 14 126 8 21 0.89
126 4 47 -23 0 0 13 26 25 26 10 -34 125 39 9 126 30 34 125 14 22 126 55 45 0.89
126 53 8 -22 0 0 13 26 17 27 9 -35 126 27 25 127 18 59 126 2 34 127 44 15 0.89
127 42 36 -21 0 0 13 26 9 28 9 -36 127 16 48 128 8 34 126 51 51 128 33 57 0.89
128 33 17 -20 0 0 13 26 1 29 8 -38 128 7 21 128 59 23 127 42 17 129 24 53 0.89
129 25 14 -19 0 0 13 25 52 30 7 -39 128 59 8 129 51 28 128 33 56 130 17 9 0.89
130 18 30 -18 0 0 13 25 43 32 7 -40 129 52 15 130 44 56 129 26 52 131 10 48 0.89
131 13 12 -17 0 0 13 25 33 33 6 -41 130 46 44 131 39 51 130 21 10 132 5 55 0.89
132 9 25 -16 0 0 13 25 23 34 5 -43 131 42 43 132 36 18 131 16 55 133 2 37 0.89
133 7 13 -15 0 0 13 25 12 35 4 -44 132 40 15 133 34 23 132 14 13 134 0 59 0.89
134 6 45 -14 0 0 13 25 1 36 4 -45 133 39 28 134 34 14 133 13 9 135 1 8 0.89
135 8 6 -13 0 0 13 24 50 37 3 -47 134 40 29 135 35 56 134 13 50 136 3 12 0.89
136 11 25 -12 0 0 13 24 38 38 2 -48 135 43 25 136 39 39 135 16 24 137 7 20 0.89
137 16 52 -11 0 0 13 24 25 39 1 -50 136 48 25 137 45 33 136 21 0 138 13 40 0.89
138 24 35 -10 0 0 13 24 12 40 360 -51 137 55 39 138 53 47 137 27 47 139 22 25 0.89
Uncertainty in time = +/- 4 secs
Prediction of 2017 Dec 15.0
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