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Updated: 2018 Aug 30, 16:51 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 Oct 23 UT, the 78 km diameter asteroid (598) Octavia will occult a 11.2 mag star in the constellation Piscis Austrinus for observers along a path across South Australia and Queensland, running from Adelaide to Townsville.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.33 mag to 13.38 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.
Occultation of UCAC4-302-273586 by 598 Octavia on 2018 Oct 23
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
136 54 41 -39 17 15 15 22 20 33 257 -38 136 6 52 -39 20 25 137 43 13 -39 13 36 135 45 38 -39 21 41 138 5 13 -39 11 49 1.42
137 2 33 -38 43 4 15 22 27 33 256 -39 136 14 54 -38 46 20 137 50 55 -38 39 19 135 53 46 -38 47 39 138 12 51 -38 37 28 1.42
137 10 58 -38 8 44 15 22 33 32 256 -39 136 23 28 -38 12 7 137 59 11 -38 4 52 136 2 24 -38 13 29 138 21 3 -38 2 58 1.43
137 19 54 -37 34 14 15 22 40 32 255 -40 136 32 33 -37 37 45 138 8 0 -37 30 15 136 11 32 -37 39 10 138 29 49 -37 28 18 1.43
137 29 23 -36 59 35 15 22 46 32 255 -40 136 42 9 -37 3 13 138 17 23 -36 55 28 136 21 12 -37 4 41 138 39 9 -36 53 27 1.43
137 39 26 -36 24 45 15 22 53 32 255 -41 136 52 17 -36 28 31 138 27 20 -36 20 29 136 31 22 -36 30 3 138 49 4 -36 18 24 1.43
137 50 2 -35 49 44 15 23 0 31 254 -41 137 2 57 -35 53 39 138 37 52 -35 45 19 136 42 5 -35 55 15 138 59 35 -35 43 10 1.43
138 1 12 -35 14 31 15 23 6 31 254 -42 137 14 10 -35 18 35 138 49 0 -35 9 57 136 53 19 -35 20 15 139 10 42 -35 7 43 1.43
138 12 57 -34 39 6 15 23 13 31 253 -42 137 25 57 -34 43 19 139 0 44 -34 34 21 137 5 7 -34 45 3 139 22 26 -34 32 2 1.44
138 25 17 -34 3 27 15 23 20 30 253 -43 137 38 18 -34 7 51 139 13 6 -33 58 30 137 17 28 -34 9 39 139 34 49 -33 56 7 1.44
138 38 15 -33 27 33 15 23 26 30 252 -43 137 51 14 -33 32 8 139 26 5 -33 22 25 137 30 24 -33 34 2 139 47 50 -33 19 56 1.44
138 51 50 -32 51 25 15 23 33 30 252 -44 138 4 46 -32 56 12 139 39 44 -32 46 4 137 43 55 -32 58 10 140 1 31 -32 43 29 1.44
139 6 3 -32 15 0 15 23 40 29 252 -44 138 18 55 -32 20 0 139 54 4 -32 9 26 137 58 3 -32 22 3 140 15 54 -32 6 44 1.44
139 20 58 -31 38 18 15 23 46 29 251 -45 138 33 43 -31 43 31 140 9 6 -31 32 29 138 12 48 -31 45 41 140 31 0 -31 29 41 1.44
139 36 33 -31 1 17 15 23 53 28 251 -45 138 49 10 -31 6 45 140 24 52 -30 55 13 138 28 12 -31 9 1 140 46 51 -30 52 17 1.45
139 52 53 -30 23 56 15 24 0 28 250 -46 139 5 20 -30 29 40 140 41 23 -30 17 36 138 44 18 -30 32 2 141 3 28 -30 14 32 1.45
140 9 58 -29 46 15 15 24 6 27 250 -46 139 22 12 -29 52 15 140 58 43 -29 39 36 139 1 5 -29 54 44 141 20 55 -29 36 25 1.45
140 27 50 -29 8 10 15 24 13 27 249 -47 139 39 50 -29 14 28 141 16 52 -29 1 13 139 18 37 -29 17 5 141 39 13 -28 57 52 1.45
140 46 33 -28 29 42 15 24 20 26 249 -47 139 58 15 -28 36 19 141 35 55 -28 22 23 139 36 55 -28 39 4 141 58 26 -28 18 52 1.45
141 6 8 -27 50 46 15 24 26 26 249 -48 140 17 30 -27 57 44 141 55 54 -27 43 6 139 56 2 -28 0 38 142 18 36 -27 39 24 1.46
141 26 40 -27 11 23 15 24 33 25 248 -48 140 37 38 -27 18 43 142 16 52 -27 3 17 140 16 1 -27 21 47 142 39 47 -26 59 24 1.46
141 48 12 -26 31 28 15 24 40 25 248 -49 140 58 43 -26 39 13 142 38 54 -26 22 56 140 36 54 -26 42 27 143 2 5 -26 18 50 1.46
142 10 47 -25 51 0 15 24 46 24 247 -49 141 20 48 -25 59 11 143 2 5 -25 41 59 140 58 46 -26 2 36 143 25 33 -25 37 39 1.46
142 34 31 -25 9 55 15 24 53 24 247 -50 141 43 56 -25 18 36 143 26 30 -25 0 22 141 21 40 -25 22 13 143 50 18 -24 55 47 1.47
142 59 30 -24 28 10 15 24 59 23 247 -50 142 8 15 -24 37 23 143 52 15 -24 18 2 141 45 42 -24 41 13 144 16 26 -24 13 9 1.47
143 25 50 -23 45 41 15 25 6 22 246 -50 142 33 48 -23 55 29 144 19 28 -23 34 53 142 10 56 -23 59 34 144 44 6 -23 29 41 1.47
143 53 39 -23 2 23 15 25 13 21 246 -51 143 0 43 -23 12 50 144 48 18 -22 50 51 142 37 29 -23 17 12 145 13 26 -22 45 18 1.47
144 23 5 -22 18 10 15 25 19 21 246 -51 143 29 8 -22 29 21 145 18 56 -22 5 49 143 5 29 -22 34 1 145 44 40 -21 59 51 1.48
144 54 21 -21 32 56 15 25 26 20 245 -52 143 59 12 -21 44 57 145 51 35 -21 19 38 143 35 4 -21 49 57 146 18 1 -21 13 12 1.48
145 27 39 -20 46 33 15 25 33 19 245 -52 144 31 6 -20 59 30 146 26 31 -20 32 10 144 6 25 -21 4 53 146 53 46 -20 25 11 1.48
146 3 17 -19 58 49 15 25 39 18 244 -52 145 5 6 -20 12 52 147 4 6 -19 43 11 144 39 45 -20 18 42 147 32 20 -19 35 34 1.49
146 41 36 -19 9 34 15 25 46 17 244 -52 145 41 27 -19 24 52 147 44 45 -18 52 26 145 15 21 -19 31 13 148 14 13 -18 44 4 1.49
147 23 3 -18 18 30 15 25 53 16 244 -53 146 20 33 -18 35 18 148 29 6 -17 59 34 145 53 31 -18 42 14 149 0 4 -17 50 15 1.50
148 8 17 -17 25 16 15 25 59 15 243 -53 147 2 53 -17 43 53 149 17 57 -17 4 5 146 34 43 -17 51 31 149 50 51 -16 53 36 1.51
Uncertainty in time = +/- 3 secs
Prediction of 2018 Aug 30.0
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