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Updated: 2017 JUL 04, 19:39 UT
Event Rank : 60
(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 2017 Dec 14 UT, the 42 km diameter asteroid (657) Gunlod will occult a 11.6 mag star in the constellation Sextans for observers along a narrow path across north-eastern Australia, close to Brisbane and along the Queensland coast to slightly inland of Ingham, then across the Cape York Peninsula to north of Karumba and the north-eastern corner of The Northern Territory (and across the South Island of New Zealand at Invercargill just before sunrise).
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.92 mag to 15.50 mag (the magnitude of the asteroid) for at most 3.0 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
169 39 22 -50 0 0 16 35 35 34 25 0 169 11 48 170 6 50 168 18 36 170 59 18 1.04
169 2 6 -49 0 0 16 35 27 35 26 -1 168 34 58 169 29 8 167 42 36 170 20 47 1.04
168 24 24 -48 0 0 16 35 20 36 27 -2 167 57 40 168 51 3 167 6 3 169 41 56 1.05
167 46 15 -47 0 0 16 35 12 37 28 -3 167 19 53 168 12 31 166 28 59 169 2 42 1.05
167 7 37 -46 0 0 16 35 5 37 29 -4 166 41 36 167 33 33 165 51 20 168 23 5 1.05
166 28 30 -45 0 0 16 34 57 38 30 -5 166 2 47 166 54 7 165 13 7 167 43 3 1.05
165 48 50 -44 0 0 16 34 49 38 31 -6 165 23 24 166 14 11 164 34 17 167 2 33 1.05
165 8 38 -43 0 0 16 34 41 39 33 -7 164 43 28 165 33 43 163 54 50 166 21 35 1.05
164 27 51 -42 0 0 16 34 32 40 34 -8 164 2 55 164 52 42 163 14 44 165 40 7 1.05
163 46 28 -41 0 0 16 34 24 40 35 -9 163 21 44 164 11 6 162 33 58 164 58 6 1.05
163 4 26 -40 0 0 16 34 15 41 37 -10 162 39 54 163 28 53 161 52 29 164 15 31 1.05
162 21 44 -39 0 0 16 34 7 41 38 -11 161 57 22 162 46 1 161 10 15 163 32 19 1.06
161 38 20 -38 0 0 16 33 58 41 40 -12 161 14 6 162 2 28 160 27 16 162 48 29 1.06
160 54 11 -37 0 0 16 33 49 42 41 -13 160 30 4 161 18 11 159 43 27 162 3 59 1.06
160 9 15 -36 0 0 16 33 39 42 42 -14 159 45 14 160 33 9 158 58 48 161 18 44 1.06
159 23 29 -35 0 0 16 33 30 42 44 -16 158 59 32 159 47 18 158 13 14 160 32 44 1.06
158 36 50 -34 0 0 16 33 21 43 46 -17 158 12 57 159 0 36 157 26 44 159 45 55 1.06
157 49 16 -33 0 0 16 33 11 43 47 -18 157 25 24 158 13 0 156 39 15 158 58 15 1.06
157 0 42 -32 0 0 16 33 1 43 49 -19 156 36 51 157 24 26 155 50 42 158 9 39 1.07
156 11 6 -31 0 0 16 32 51 43 50 -20 155 47 14 156 34 51 155 1 2 157 20 5 1.07
155 20 24 -30 0 0 16 32 41 43 52 -22 154 56 29 155 44 11 154 10 11 156 29 28 1.07
154 28 31 -29 0 0 16 32 31 43 54 -23 154 4 32 154 52 21 153 18 4 155 37 46 1.07
153 35 22 -28 0 0 16 32 21 43 55 -24 153 11 17 153 59 18 152 24 37 154 44 52 1.07
152 40 53 -27 0 0 16 32 11 43 57 -26 152 16 40 153 4 56 151 29 44 153 50 43 1.07
151 44 57 -26 0 0 16 32 0 43 59 -27 151 20 35 152 9 10 150 33 19 152 55 13 1.08
150 47 29 -25 0 0 16 31 50 42 60 -28 150 22 55 151 11 53 149 35 15 151 58 16 1.08
149 48 21 -24 0 0 16 31 39 42 62 -30 149 23 33 150 12 58 148 35 25 150 59 46 1.08
148 47 25 -23 0 0 16 31 28 42 63 -31 148 22 21 149 12 18 147 33 40 149 59 35 1.08
147 44 34 -22 0 0 16 31 17 41 65 -32 147 19 10 148 9 45 146 29 50 148 57 35 1.08
146 39 36 -21 0 0 16 31 6 41 67 -34 146 13 50 147 5 8 145 23 45 147 53 37 1.08
145 32 20 -20 0 0 16 30 55 40 68 -35 145 6 8 145 58 17 144 15 11 146 47 30 1.09
144 22 33 -19 0 0 16 30 44 39 70 -37 143 55 52 144 48 59 143 3 54 145 39 4 1.09
143 9 59 -18 0 0 16 30 33 39 71 -38 142 42 44 143 36 58 141 49 37 144 28 3 1.09
141 54 22 -17 0 0 16 30 21 38 73 -40 141 26 27 142 21 59 140 31 58 143 14 12 1.09
140 35 18 -16 0 0 16 30 10 37 74 -41 140 6 37 141 3 39 139 10 35 141 57 13 1.10
139 12 24 -15 0 0 16 29 58 36 75 -43 138 42 49 139 41 36 137 44 56 140 36 43 1.10
137 45 7 -14 0 0 16 29 46 34 77 -45 137 14 29 138 15 20 136 14 25 139 12 15 1.10
136 12 48 -13 0 0 16 29 34 33 78 -46 135 40 55 136 44 13 134 38 14 137 43 16 1.10
134 34 39 -12 0 0 16 29 22 32 79 -48 134 1 14 135 7 30 132 55 24 136 9 6 1.11
132 49 34 -11 0 0 16 29 10 30 80 -50 132 14 18 133 24 10 131 4 32 134 28 51 1.11
130 56 7 -10 0 0 16 28 58 28 81 -52 130 18 30 131 32 54 129 3 44 132 41 24 1.12
Uncertainty in time = +/- 3 secs
Prediction of 2017 Jul 4.0
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