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Updated: 2020 SEP 14, 03:46 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 2020 Nov 13 UT, the 81.6 km diameter asteroid (385) Ilmatar will occult a 10.5 mag star in the constellation Sagittarius for observers along a path across Australia crossing central New South Wales and western Victoria at low elevation.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.20 mag to 13.60 mag (the magnitude of the asteroid) for at most 2.7 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, inparticular 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 TYC 6899-00240-1 by 385 Ilmatar on 2020 Nov 13
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
135 18 44 -41 48 23 12 42 34.7 25 254 -24 134 17 38 -41 49 20 136 21 32 -41 46 29 133 52 12 -41 49 28 136 48 43 -41 45 22 1.23
135 41 32 -41 27 55 12 42 35.8 24 253 -24 134 40 7 -41 29 13 136 44 42 -41 25 38 134 14 33 -41 29 30 137 12 4 -41 24 21 1.23
136 4 41 -41 7 14 12 42 36.8 24 253 -25 135 2 55 -41 8 54 137 8 16 -41 4 34 134 37 13 -41 9 19 137 35 49 -41 3 6 1.23
136 28 13 -40 46 19 12 42 37.9 23 252 -25 135 26 3 -40 48 22 137 32 14 -40 43 14 135 0 13 -40 48 56 137 59 59 -40 41 35 1.23
136 52 9 -40 25 10 12 42 38.9 23 252 -26 135 49 34 -40 27 37 137 56 39 -40 21 39 135 23 33 -40 28 21 138 24 38 -40 19 48 1.24
137 16 30 -40 3 46 12 42 40.0 23 252 -26 136 13 27 -40 6 37 138 21 32 -39 59 47 135 47 16 -40 7 31 138 49 45 -39 57 44 1.24
137 41 18 -39 42 5 12 42 41.1 22 251 -27 136 37 45 -39 45 23 138 46 55 -39 37 38 136 11 23 -39 46 28 139 15 24 -39 35 21 1.24
138 6 35 -39 20 8 12 42 42.1 22 251 -27 137 2 30 -39 23 53 139 12 50 -39 15 9 136 35 55 -39 25 9 139 41 37 -39 12 38 1.24
138 32 24 -38 57 51 12 42 43.2 21 251 -28 137 27 43 -39 2 7 139 39 19 -38 52 20 137 0 54 -39 3 34 140 8 26 -38 49 34 1.24
138 58 45 -38 35 15 12 42 44.3 21 250 -28 137 53 25 -38 40 2 140 6 26 -38 29 9 137 26 21 -38 41 41 140 35 55 -38 26 7 1.24
139 25 43 -38 12 18 12 42 45.3 20 250 -29 138 19 40 -38 17 38 140 34 13 -38 5 34 137 52 20 -38 19 31 141 4 6 -38 2 15 1.24
139 53 19 -37 48 59 12 42 46.4 20 250 -29 138 46 29 -37 54 54 141 2 44 -37 41 34 138 18 51 -37 57 0 141 33 3 -37 37 56 1.24
140 21 37 -37 25 14 12 42 47.5 19 249 -30 139 13 55 -37 31 48 141 32 3 -37 17 6 138 45 58 -37 34 9 142 2 50 -37 13 7 1.24
140 50 40 -37 1 3 12 42 48.5 19 249 -30 139 42 2 -37 8 18 142 2 13 -36 52 8 139 13 43 -37 10 55 142 33 33 -36 47 47 1.24
141 20 33 -36 36 23 12 42 49.6 18 248 -31 140 10 52 -36 44 23 142 33 21 -36 26 37 139 42 9 -36 47 17 143 5 17 -36 21 51 1.25
141 51 21 -36 11 12 12 42 50.6 18 248 -31 140 40 30 -36 19 59 143 5 32 -36 0 29 140 11 21 -36 23 12 143 38 9 -35 55 17 1.25
142 23 8 -35 45 26 12 42 51.7 17 248 -32 141 10 59 -35 55 6 143 38 54 -35 33 41 140 41 21 -35 58 39 144 12 17 -35 27 58 1.25
142 56 2 -35 19 1 12 42 52.8 17 247 -33 141 42 26 -35 29 39 144 13 35 -35 6 7 141 12 16 -35 33 34 144 47 51 -34 59 51 1.25
143 30 11 -34 51 54 12 42 53.8 16 247 -33 142 14 56 -35 3 36 144 49 45 -34 37 42 141 44 10 -35 7 55 145 25 2 -34 30 48 1.25
144 5 43 -34 23 58 12 42 54.9 15 246 -34 142 48 37 -34 36 52 145 27 37 -34 8 19 142 17 9 -34 41 38 146 4 5 -34 0 41 1.26
144 42 50 -33 55 9 12 42 56.0 15 246 -34 143 23 36 -34 9 23 146 7 28 -33 37 48 142 51 23 -34 14 39 146 45 19 -33 29 19 1.26
145 21 47 -33 25 17 12 42 57.0 14 246 -35 144 0 5 -33 41 3 146 49 37 -33 5 59 143 26 58 -33 46 52 147 29 9 -32 56 29 1.26
146 2 51 -32 54 12 12 42 58.1 13 245 -36 144 38 15 -33 11 45 147 34 32 -32 32 35 144 4 7 -33 18 12 148 16 9 -32 21 52 1.27
146 46 25 -32 21 42 12 42 59.1 13 245 -37 145 18 24 -32 41 19 148 22 51 -31 57 17 144 43 4 -32 48 30 149 7 4 -31 45 3 1.27
147 33 2 -31 47 30 12 43 0.2 12 244 -37 146 0 50 -32 9 36 149 15 26 -31 19 35 145 24 5 -32 17 38 150 3 6 -31 5 21 1.28
148 23 24 -31 11 10 12 43 1.3 11 244 -38 146 46 2 -31 36 19 150 13 40 -30 38 43 146 7 34 -31 45 22 151 6 7 -30 21 45 1.29
149 18 37 -30 32 7 12 43 2.3 10 243 -39 147 34 36 -31 1 8 151 19 48 -29 53 26 146 54 1 -31 11 25 152 19 32 -29 32 20 1.30
150 20 22 -29 49 26 12 43 3.4 9 243 -40 148 27 24 -30 23 34 152 38 11 -29 1 19 147 44 6 -30 35 26 153 51 0 -28 32 54 1.32
151 31 38 -29 1 25 12 43 4.5 7 242 -41 149 25 47 -29 42 52 154 19 40 -27 56 24 148 38 52 -29 56 49 156 8 30 -27 7 57 1.36
152 58 45 -28 4 37 12 43 5.5 6 241 -42 150 31 56 -28 57 51 157 29 52 -26 2 26 149 39 54 -29 14 42 ... .. .. .. .. .. 1.42
155 1 26 -26 48 7 12 43 6.6 4 240 -44 151 50 5 -28 6 10 ... .. .. .. .. .. 150 49 55 -28 27 35 ... .. .. .. .. .. 1.66
Uncertainty in time = +/- 1 secs
Prediction of 2020 Sep 14.0
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