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Updated: 2020 Jul 01, 04:58 UT
Event Rank : 86
(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 Aug 17 UT, the 27 km diameter asteroid (1108) Demeter will occult a 10.5 mag star in the constellation Cygnus for observers along a slightly uncertain path across northern Queensland, Northern Territory and southern West Australia, running from Mossman to Point D'Entrecasteaux, passing near Kalgoorlie.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.89 mag to 14.36 mag (the magnitude of the asteroid) for at most 5.6 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindlyprovided by Hugh Harris, astrometry for the asteroid kindly provided by the IAUMinor 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 theGaia 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 2700-00609-1 by 1108 Demeter on 2020 Aug 17
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
114 41 47 -37 0 0 15 18 58.6 17 3 -62 114 21 16 115 2 25 113 57 28 115 26 41 1.57
115 31 52 -36 0 0 15 18 43.3 18 3 -63 115 11 19 115 52 34 114 47 27 116 16 55 1.57
116 24 7 -35 0 0 15 18 27.0 19 2 -64 116 3 28 116 44 54 115 39 30 117 9 22 1.57
117 18 35 -34 0 0 15 18 9.5 20 1 -66 116 57 49 117 39 30 116 33 43 118 4 7 1.57
118 15 25 -33 0 0 15 17 50.8 21 0 -67 117 54 29 118 36 29 117 30 13 119 1 18 1.57
119 14 43 -32 0 0 15 17 30.8 22 360 -68 118 53 36 119 36 0 118 29 6 120 1 3 1.57
120 16 39 -31 0 0 15 17 9.6 23 359 -69 119 55 17 120 38 10 119 30 32 121 3 31 1.57
121 21 23 -30 0 0 15 16 47.1 24 358 -71 120 59 44 121 43 11 120 34 40 122 8 54 1.57
122 29 7 -29 0 0 15 16 23.1 25 357 -72 122 7 9 122 51 17 121 41 42 123 17 24 1.56
123 40 7 -28 0 0 15 15 57.6 26 356 -73 123 17 45 124 2 41 122 51 51 124 29 18 1.56
124 54 39 -27 0 0 15 15 30.5 27 355 -75 124 31 49 125 17 42 124 5 24 125 44 55 1.56
126 13 5 -26 0 0 15 15 1.8 28 354 -76 125 49 42 126 36 42 125 22 40 127 4 36 1.55
127 35 49 -25 0 0 15 14 31.1 29 353 -77 127 11 47 128 0 7 126 44 1 128 28 50 1.55
129 3 23 -24 0 0 15 13 58.5 30 351 -79 128 38 35 129 28 29 128 9 58 129 58 11 1.55
130 36 27 -23 0 0 15 13 23.5 30 350 -80 130 10 43 131 2 30 129 41 4 131 33 23 1.54
132 15 49 -22 0 0 15 12 46.2 31 348 -81 131 48 58 132 43 3 131 18 4 133 15 23 1.54
134 2 37 -21 0 0 15 12 5.9 32 347 -82 133 34 23 134 31 18 133 1 57 135 5 26 1.54
135 58 20 -20 0 0 15 11 22.4 32 345 -83 135 28 22 136 28 51 134 54 1 137 5 17 1.53
138 5 5 -19 0 0 15 10 34.8 33 343 -83 137 32 51 138 38 1 136 56 2 139 17 28 1.53
139 0 0 -18 35 48 15 10 14.3 33 342 -82 -18 21 19 -18 50 23 -18 4 31 -19 7 34 1.53
140 0 0 -18 10 34 15 9 52.0 33 341 -82 -17 56 13 -18 25 1 -17 39 35 -18 42 2 1.53
141 0 0 -17 46 35 15 9 29.7 33 340 -81 -17 32 22 -18 0 54 -17 15 52 -18 17 46 1.53
142 0 0 -17 23 50 15 9 7.6 33 340 -81 -17 9 44 -17 38 2 -16 53 22 -17 54 45 1.53
143 0 0 -17 2 17 15 8 45.6 33 339 -80 -16 48 17 -17 16 22 -16 32 3 -17 32 57 1.53
144 0 0 -16 41 55 15 8 23.6 33 338 -80 -16 28 2 -16 55 54 -16 11 55 -17 12 21 1.53
145 0 0 -16 22 44 15 8 1.9 33 337 -79 -16 8 56 -16 36 37 -15 52 56 -16 52 58 1.53
146 0 0 -16 4 43 15 7 40.2 33 336 -78 -15 51 0 -16 18 31 -15 35 6 -16 34 45 1.53
147 0 0 -15 47 51 15 7 18.7 33 335 -77 -15 34 13 -16 1 33 -15 18 24 -16 17 42 1.53
Uncertainty in time = +/- 10 secs
Prediction of 2020 Jul 1.0
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