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Updated: 2018 Jul 06, 21:42 UT
Event Rank : 46
(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 Aug 27 UT, the 49 km diameter asteroid (2356) Hirons will occult a 12.2 mag star in the constellation Aquila for observers along a significantly uncertain path across western Queensland and eastern South Australia, passing over Cloncurry and Whyalla.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.91 mag to 16.09 mag (the magnitude of the asteroid) for at most 5.8 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 UCAC4-433-088658 by 2356 Hirons on 2018 Aug 27
Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2 Alt
E. Longitude Latitude U.T. Alt Az Alt Crn
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
144 20 23 - 9 44 16 12 31 43 67 284 -62 144 34 16 - 9 48 18 144 6 32 - 9 40 14 145 19 27 -10 1 21 143 21 51 - 9 27 8 0.42
144 5 31 -10 25 46 12 31 53 67 286 -62 144 19 25 -10 29 49 143 51 38 -10 21 44 145 4 42 -10 42 53 143 6 52 -10 8 36 0.42
143 50 49 -11 7 20 12 32 2 67 288 -62 144 4 45 -11 11 23 143 36 54 -11 3 16 144 50 7 -11 24 29 142 52 3 -10 50 7 0.42
143 36 16 -11 48 57 12 32 12 67 289 -62 143 50 14 -11 53 0 143 22 20 -11 44 53 144 35 43 -12 6 8 142 37 23 -11 31 42 0.42
143 21 54 -12 30 38 12 32 21 67 291 -62 143 35 54 -12 34 42 143 7 55 -12 26 33 144 21 29 -12 47 52 142 22 52 -12 13 20 0.42
143 7 40 -13 12 23 12 32 31 67 293 -61 143 21 43 -13 16 28 142 53 40 -13 8 18 144 7 26 -13 29 40 142 8 29 -12 55 3 0.42
142 53 36 -13 54 13 12 32 41 67 295 -61 143 7 41 -13 58 19 142 39 33 -13 50 7 143 53 32 -14 11 33 141 54 15 -13 36 50 0.42
142 39 41 -14 36 9 12 32 50 67 296 -61 142 53 48 -14 40 15 142 25 36 -14 32 2 143 39 48 -14 53 32 141 40 10 -14 18 42 0.43
142 25 55 -15 18 9 12 33 0 67 298 -61 142 40 5 -15 22 16 142 11 47 -15 14 2 143 26 13 -15 35 36 141 26 12 -15 0 40 0.43
142 12 17 -16 0 16 12 33 9 66 300 -60 142 26 29 -16 4 24 141 58 6 -15 56 8 143 12 47 -16 17 46 141 12 22 -15 42 44 0.43
141 58 47 -16 42 30 12 33 19 66 301 -60 142 13 3 -16 46 38 141 44 33 -16 38 21 142 59 30 -17 0 3 140 58 40 -16 24 54 0.43
141 45 25 -17 24 50 12 33 28 66 303 -60 141 59 44 -17 29 0 141 31 8 -17 20 40 142 46 23 -17 42 27 140 45 5 -17 7 10 0.43
141 32 12 -18 7 18 12 33 38 66 304 -59 141 46 34 -18 11 28 141 17 51 -18 3 7 142 33 23 -18 24 59 140 31 37 -17 49 34 0.43
141 19 6 -18 49 53 12 33 48 65 306 -59 141 33 32 -18 54 4 141 4 42 -18 45 41 142 20 33 -19 7 38 140 18 17 -18 32 5 0.43
141 6 8 -19 32 37 12 33 57 65 307 -59 141 20 38 -19 36 49 140 51 40 -19 28 24 142 7 51 -19 50 26 140 5 3 -19 14 44 0.43
140 53 17 -20 15 29 12 34 7 65 309 -58 141 7 51 -20 19 42 140 38 45 -20 11 15 141 55 18 -20 33 23 139 51 56 -19 57 32 0.43
140 40 34 -20 58 30 12 34 16 65 310 -58 140 55 12 -21 2 45 140 25 58 -20 54 16 141 42 52 -21 16 29 139 38 55 -20 40 29 0.43
140 27 58 -21 41 42 12 34 26 64 312 -58 140 42 40 -21 45 58 140 13 18 -21 37 26 141 30 35 -21 59 45 139 26 1 -21 23 36 0.43
140 15 29 -22 25 3 12 34 35 64 313 -57 140 30 16 -22 29 20 140 0 45 -22 20 46 141 18 26 -22 43 12 139 13 13 -22 6 52 0.43
140 3 8 -23 8 36 12 34 45 63 314 -57 140 17 59 -23 12 54 139 48 18 -23 4 17 141 6 25 -23 26 50 139 0 32 -22 50 19 0.44
139 50 53 -23 52 19 12 34 55 63 316 -57 140 5 50 -23 56 39 139 35 58 -23 48 0 140 54 32 -24 10 39 138 47 56 -23 33 57 0.44
139 38 45 -24 36 15 12 35 4 63 317 -56 139 53 47 -24 40 36 139 23 45 -24 31 54 140 42 47 -24 54 41 138 35 27 -24 17 47 0.44
139 26 44 -25 20 23 12 35 14 62 318 -56 139 41 52 -25 24 46 139 11 39 -25 16 1 140 31 10 -25 38 55 138 23 3 -25 1 49 0.44
139 14 50 -26 4 45 12 35 23 62 319 -55 139 30 4 -26 9 9 138 59 39 -26 0 21 140 19 41 -26 23 23 138 10 45 -25 46 5 0.44
139 3 3 -26 49 20 12 35 33 61 321 -55 139 18 22 -26 53 46 138 47 46 -26 44 55 140 8 20 -27 8 5 137 58 32 -26 30 33 0.44
138 51 22 -27 34 10 12 35 42 61 322 -55 139 6 48 -27 38 37 138 35 59 -27 29 43 139 57 7 -27 53 2 137 46 25 -27 15 16 0.44
138 39 48 -28 19 15 12 35 52 60 323 -54 138 55 21 -28 23 44 138 24 18 -28 14 46 139 46 2 -28 38 14 137 34 24 -28 0 14 0.44
138 28 21 -29 4 36 12 36 2 60 324 -54 138 44 1 -29 9 7 138 12 44 -29 0 6 139 35 5 -29 23 43 137 22 27 -28 45 28 0.44
138 17 1 -29 50 14 12 36 11 59 325 -53 138 32 48 -29 54 47 138 1 17 -29 45 42 139 24 17 -30 9 29 137 10 37 -29 30 58 0.44
138 5 48 -30 36 10 12 36 21 59 326 -53 138 21 42 -30 40 44 137 49 56 -30 31 35 139 13 37 -30 55 33 136 58 51 -30 16 45 0.44
137 54 41 -31 22 23 12 36 30 58 327 -52 138 10 44 -31 27 0 137 38 41 -31 17 47 139 3 5 -31 41 55 136 47 11 -31 2 50 0.44
137 43 41 -32 8 56 12 36 40 57 328 -52 137 59 52 -32 13 35 137 27 33 -32 4 18 138 52 42 -32 28 37 136 35 37 -31 49 14 0.44
137 32 48 -32 55 50 12 36 49 57 328 -51 137 49 9 -33 0 31 137 16 31 -32 51 9 138 42 27 -33 15 40 136 24 7 -32 35 58 0.44
137 22 3 -33 43 4 12 36 59 56 329 -51 137 38 32 -33 47 47 137 5 37 -33 38 21 138 32 22 -34 3 4 136 12 43 -33 23 3 0.44
137 11 25 -34 30 41 12 37 9 56 330 -51 137 28 4 -34 35 27 136 54 49 -34 25 56 138 22 26 -34 50 51 136 1 25 -34 10 30 0.45
137 0 54 -35 18 41 12 37 18 55 331 -50 137 17 44 -35 23 30 136 44 8 -35 13 53 138 12 40 -35 39 3 135 50 11 -34 58 19 0.45
136 50 31 -36 7 6 12 37 28 54 332 -50 137 7 31 -36 11 57 136 33 34 -36 2 15 138 3 4 -36 27 39 135 39 4 -35 46 33 0.45
136 40 16 -36 55 57 12 37 37 54 332 -49 136 57 28 -37 0 50 136 23 8 -36 51 3 137 53 38 -37 16 41 135 28 1 -36 35 12 0.45
Uncertainty in time = +/- 10 secs
Prediction of 2018 Jul 6.0
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