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Updated: 2020 Aug 29, 02:35 UT
Event Rank : 100
(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 Oct 26 UT, the 147 km diameter asteroid (51) Nemausa will occult a 10.8 mag star in the constellation Taurus for observers along a path across western South Australia and south-eastern West Australia, during morning twilight.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.09 mag to 11.37 mag (the magnitude of the asteroid) for at most 19.6 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 TYC 0682-00277-1 by 51 Nemausa on 2020 Oct 26
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
125 43 6 -37 0 0 20 6 38.6 35 320 -7 124 12 43 127 15 26 123 56 45 127 32 11 1.29
126 22 6 -36 0 0 20 6 23.2 36 319 -7 124 52 5 127 54 6 124 36 11 128 10 47 1.29
127 2 25 -35 0 0 20 6 7.5 36 318 -6 125 32 41 128 34 10 125 16 50 128 50 48 1.28
127 44 5 -34 0 0 20 5 51.4 37 317 -6 126 14 32 129 15 39 125 58 43 129 32 16 1.28
128 27 6 -33 0 0 20 5 35.1 37 316 -6 126 57 41 129 58 37 126 41 53 130 15 13 1.28
129 11 32 -32 0 0 20 5 18.5 37 314 -6 127 42 8 130 43 4 127 26 21 130 59 41 1.28
129 57 25 -31 0 0 20 5 1.5 38 313 -6 128 27 56 131 29 4 128 12 9 131 45 43 1.28
130 44 47 -30 0 0 20 4 44.3 38 312 -5 129 15 9 132 16 41 128 59 21 132 33 22 1.28
131 33 44 -29 0 0 20 4 26.8 38 311 -5 130 3 50 133 5 57 129 47 59 133 22 43 1.27
132 24 17 -28 0 0 20 4 9.0 38 309 -5 130 54 2 133 56 57 130 38 7 134 13 49 1.27
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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