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Updated: 2019 Jul 21, 04:58 UT
Event Rank : 30
(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 2019 Aug 16 UT, the 22 km diameter asteroid (1317) Silvretta will occult a 11.7 mag star in the constellation Ara for observers along a significantly uncertain path across western South Australia and Northern Territory, running from Cape Nuyts to Cobourg Peninsula.
In the case of an occultation, the combined light of the asteroid and the star will drop by 4.13 mag to 15.80 mag (the magnitude of the asteroid) for at most 2.5 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, 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 UCAC4-213-148981 by 1317 Silvretta on 2019 Aug 16
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
132 34 46 -36 52 56 11 24 52 76 213 -34 132 27 16 -36 53 4 132 42 16 -36 52 47 131 39 42 -36 53 45 133 29 54 -36 51 35 -0.14
132 32 33 -36 7 18 11 25 1 76 212 -34 132 25 8 -36 7 27 132 39 59 -36 7 9 131 38 2 -36 8 8 133 27 9 -36 5 57 -0.14
132 30 27 -35 21 33 11 25 11 75 210 -34 132 23 5 -35 21 41 132 37 48 -35 21 24 131 36 26 -35 22 22 133 24 31 -35 20 12 -0.14
132 28 25 -34 35 39 11 25 20 74 209 -35 132 21 8 -34 35 47 132 35 43 -34 35 29 131 34 54 -34 36 29 133 22 0 -34 34 17 -0.14
132 26 29 -33 49 35 11 25 29 74 207 -35 132 19 16 -33 49 44 132 33 43 -33 49 26 131 33 27 -33 50 26 133 19 35 -33 48 14 -0.14
132 24 39 -33 3 22 11 25 38 73 206 -35 132 17 29 -33 3 31 132 31 49 -33 3 13 131 32 5 -33 4 14 133 17 17 -33 2 0 -0.14
132 22 54 -32 16 59 11 25 47 72 205 -35 132 15 48 -32 17 8 132 30 0 -32 16 50 131 30 47 -32 17 51 133 15 5 -32 15 36 -0.14
132 21 14 -31 30 25 11 25 57 72 204 -35 132 14 12 -31 30 34 132 28 17 -31 30 15 131 29 33 -31 31 17 133 13 0 -31 29 1 -0.14
132 19 40 -30 43 39 11 26 6 71 203 -35 132 12 41 -30 43 48 132 26 39 -30 43 29 131 28 24 -30 44 32 133 11 0 -30 42 15 -0.15
132 18 11 -29 56 41 11 26 15 70 202 -35 132 11 15 -29 56 50 132 25 7 -29 56 31 131 27 19 -29 57 35 133 9 7 -29 55 16 -0.15
132 16 47 -29 9 29 11 26 24 70 202 -35 132 9 54 -29 9 39 132 23 40 -29 9 20 131 26 18 -29 10 24 133 7 20 -29 8 4 -0.15
132 15 28 -28 22 5 11 26 33 69 201 -35 132 8 39 -28 22 14 132 22 18 -28 21 55 131 25 22 -28 23 1 133 5 39 -28 20 38 -0.15
132 14 15 -27 34 25 11 26 43 68 200 -35 132 7 28 -27 34 35 132 21 2 -27 34 15 131 24 30 -27 35 22 133 4 4 -27 32 58 -0.15
132 13 7 -26 46 31 11 26 52 67 200 -35 132 6 23 -26 46 41 132 19 50 -26 46 21 131 23 43 -26 47 29 133 2 35 -26 45 2 -0.15
132 12 4 -25 58 20 11 27 1 67 199 -35 132 5 23 -25 58 30 132 18 45 -25 58 10 131 23 0 -25 59 20 133 1 12 -25 56 51 -0.15
132 11 6 -25 9 53 11 27 10 66 198 -35 132 4 28 -25 10 3 132 17 44 -25 9 42 131 22 22 -25 10 54 132 59 54 -25 8 22 -0.15
132 10 14 -24 21 8 11 27 19 65 198 -35 132 3 38 -24 21 18 132 16 49 -24 20 57 131 21 48 -24 22 10 132 58 43 -24 19 36 -0.15
132 9 27 -23 32 4 11 27 29 64 197 -35 132 2 53 -23 32 15 132 16 0 -23 31 53 131 21 19 -23 33 8 132 57 39 -23 30 30 -0.15
132 8 45 -22 42 41 11 27 38 63 197 -35 132 2 14 -22 42 52 132 15 16 -22 42 30 131 20 55 -22 43 46 132 56 40 -22 41 6 -0.15
132 8 9 -21 52 57 11 27 47 63 197 -35 132 1 40 -21 53 8 132 14 38 -21 52 46 131 20 35 -21 54 4 132 55 47 -21 51 20 -0.15
132 7 39 -21 2 51 11 27 56 62 196 -35 132 1 12 -21 3 2 132 14 5 -21 2 40 131 20 21 -21 4 0 132 55 1 -21 1 12 -0.15
132 7 14 -20 12 23 11 28 5 61 196 -35 132 0 50 -20 12 34 132 13 39 -20 12 11 131 20 11 -20 13 33 132 54 21 -20 10 42 -0.15
132 6 55 -19 21 30 11 28 15 60 195 -35 132 0 33 -19 21 42 132 13 18 -19 21 18 131 20 7 -19 22 42 132 53 48 -19 19 48 -0.15
132 6 43 -18 30 13 11 28 24 59 195 -35 132 0 22 -18 30 25 132 13 3 -18 30 0 131 20 8 -18 31 27 132 53 22 -18 28 28 -0.16
132 6 36 -17 38 28 11 28 33 59 195 -35 132 0 17 -17 38 41 132 12 55 -17 38 16 131 20 15 -17 39 45 132 53 2 -17 36 41 -0.16
132 6 36 -16 46 16 11 28 42 58 194 -35 132 0 19 -16 46 29 132 12 53 -16 46 3 131 20 27 -16 47 35 132 52 49 -16 44 26 -0.16
132 6 42 -15 53 34 11 28 51 57 194 -35 132 0 27 -15 53 47 132 12 58 -15 53 21 131 20 45 -15 54 55 132 52 44 -15 51 42 0.16
132 6 55 -15 0 21 11 29 1 56 194 -35 132 0 41 -15 0 34 132 13 9 -15 0 7 131 21 10 -15 1 45 132 52 46 -14 58 26 0.16
132 7 15 -14 6 35 11 29 10 55 194 -35 132 1 3 -14 6 49 132 13 28 -14 6 21 131 21 40 -14 8 2 132 52 55 -14 4 37 0.16
132 7 43 -13 12 15 11 29 19 54 193 -35 132 1 31 -13 12 29 132 13 54 -13 12 0 131 22 18 -13 13 44 132 53 13 -13 10 13 0.16
132 8 18 -12 17 18 11 29 28 53 193 -35 132 2 8 -12 17 32 132 14 28 -12 17 2 131 23 2 -12 18 50 132 53 39 -12 15 13 0.16
132 9 1 -11 21 42 11 29 37 52 193 -35 132 2 52 -11 21 56 132 15 10 -11 21 26 131 23 53 -11 23 17 132 54 13 -11 19 33 0.16
132 9 52 -10 25 24 11 29 46 52 193 -35 132 3 44 -10 25 40 132 16 0 -10 25 8 131 24 52 -10 27 4 132 54 57 -10 23 12 0.16
Uncertainty in time = +/- 8 secs
Prediction of 2019 Jul 21.0
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