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Updated: 2015 Dec 03, 10:56 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 2016 Jan 19 UT, the 202 km diameter asteroid (747) Winchester will occult a 11.8 mag star in the constellation Orion for observers along a path across western Queensland, western New South Wales, western Victoria and far eastern South Australia, passing over Broken Hill, Mildura and Mount Gambier.
In the case of an occultation, the combined light of the asteroid and the star will drop by only 0.4 mag to 11.0 mag (the magnitude of the asteroid) for at most 19.4 seconds. This event may be difficult to detect visually.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC.
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 2UCAC 33344093 by 747 Winchester on 2016 Jan 19
Centre Star Star Sun Path Limits Error Limits
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
140 26 38 -39 0 0 10 28 54 43 26 -5 141 40 15 139 12 29 142 0 47 138 51 37
140 39 47 -38 0 0 10 29 1 44 26 -6 141 52 18 139 26 46 142 12 31 139 6 13
140 52 8 -37 0 0 10 29 9 45 26 -7 142 3 36 139 40 11 142 23 31 139 19 56
141 3 43 -36 0 0 10 29 17 46 26 -7 142 14 11 139 52 46 142 33 50 139 32 49
141 14 34 -35 0 0 10 29 26 47 26 -8 142 24 6 140 4 36 142 43 29 139 44 55
141 24 44 -34 0 0 10 29 34 48 26 -9 142 33 22 140 15 40 142 52 31 139 56 15
141 34 15 -33 0 0 10 29 42 49 27 -9 142 42 2 140 26 3 143 0 56 140 6 52
141 43 8 -32 0 0 10 29 51 50 27 -10 142 50 7 140 35 45 143 8 48 140 16 49
141 51 26 -31 0 0 10 29 59 51 27 -11 142 57 38 140 44 50 143 16 7 140 26 6
141 59 9 -30 0 0 10 30 8 52 28 -11 143 4 38 140 53 17 143 22 54 140 34 46
142 6 19 -29 0 0 10 30 17 53 28 -12 143 11 7 141 1 9 143 29 12 140 42 51
142 12 58 -28 0 0 10 30 26 54 28 -12 143 17 7 141 8 28 143 35 1 140 50 21
142 19 7 -27 0 0 10 30 35 55 29 -13 143 22 39 141 15 15 143 40 23 140 57 18
142 24 47 -26 0 0 10 30 44 56 29 -14 143 27 44 141 21 30 143 45 18 141 3 43
142 29 59 -25 0 0 10 30 53 57 30 -14 143 32 22 141 27 16 143 49 47 141 9 39
142 34 44 -24 0 0 10 31 2 58 30 -15 143 36 36 141 32 33 143 53 52 141 15 5
142 39 3 -23 0 0 10 31 12 59 31 -16 143 40 26 141 37 23 143 57 33 141 20 3
142 42 58 -22 0 0 10 31 21 59 32 -16 143 43 52 141 41 45 144 0 52 141 24 33
142 46 27 -21 0 0 10 31 31 60 32 -17 143 46 55 141 45 42 144 3 48 141 28 38
142 49 34 -20 0 0 10 31 40 61 33 -17 143 49 37 141 49 14 144 6 22 141 32 17
142 52 18 -19 0 0 10 31 50 62 34 -18 143 51 57 141 52 21 144 8 36 141 35 31
142 54 39 -18 0 0 10 32 0 63 35 -18 143 53 56 141 55 5 144 10 30 141 38 21
142 56 39 -17 0 0 10 32 10 64 36 -19 143 55 36 141 57 25 144 12 3 141 40 47
142 58 18 -16 0 0 10 32 20 65 37 -19 143 56 56 141 59 24 144 13 18 141 42 51
142 59 37 -15 0 0 10 32 30 65 38 -20 143 57 57 142 1 1 144 14 14 141 44 33
143 0 35 -14 0 0 10 32 40 66 40 -21 143 58 39 142 2 16 144 14 52 141 45 53
143 1 15 -13 0 0 10 32 50 67 41 -21 143 59 3 142 3 11 144 15 11 141 46 52
143 1 35 -12 0 0 10 33 0 68 43 -22 143 59 9 142 3 45 144 15 13 141 47 30
143 1 36 -11 0 0 10 33 10 69 44 -22 143 58 57 142 3 59 144 14 58 141 47 48
143 1 19 -10 0 0 10 33 20 69 46 -23 143 58 29 142 3 54 144 14 27 141 47 46
Uncertainty in time = +/- 3 secs
Prediction of 2015 Dec 3.0
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