Updated: 2014 Jun 22, 08:44 UT
Event Rank : 52
(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 2014 Jul 12 UT, the 41 km diameter asteroid (577) Rhea will occult a 11.6 mag star in the constellation Scorpius for observers along a somewhat uncertain path across eastern Victoria, passing over Lakes Entrance, across central New South Wales, near Albury, over south-west and western Queensland and over Northern Territory.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.3 mag to 13.7 mag (the magnitude of the asteroid) for at most 11.5 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, 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 TYC 6787-01726-1 by 577 Rhea on 2014 Jul 12 Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2 E. Longitude Latitude U.T. Alt Az Alt o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' " Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude 151 49 7 -45 1 26 8 40 10 61 63 -22 151 32 9 -45 5 4 152 6 1 -44 57 46 150 50 9 -45 13 52 152 47 17 -44 48 38 151 12 48 -43 46 59 8 40 50 62 66 -22 150 56 11 -43 50 33 151 29 22 -43 43 24 150 15 1 -43 59 12 152 9 50 -43 34 26 150 36 26 -42 32 49 8 41 30 62 69 -21 150 20 7 -42 36 19 150 52 41 -42 29 17 149 39 44 -42 44 48 151 32 23 -42 20 29 149 59 57 -41 18 51 8 42 10 62 71 -21 149 43 56 -41 22 18 150 15 54 -41 15 23 149 4 17 -41 30 37 150 54 55 -41 6 44 149 23 20 -40 5 5 8 42 50 62 74 -20 149 7 35 -40 8 27 149 39 1 -40 1 40 148 28 37 -40 16 38 150 17 23 -39 53 10 148 46 33 -38 51 26 8 43 30 62 77 -20 148 31 4 -38 54 45 149 2 0 -38 48 5 147 52 43 -39 2 48 149 39 45 -38 39 44 148 9 35 -37 37 53 8 44 11 62 79 -19 147 54 19 -37 41 9 148 24 47 -37 34 36 147 16 34 -37 49 3 149 1 58 -37 26 24 147 32 22 -36 24 24 8 44 51 62 82 -18 147 17 20 -36 27 36 147 47 21 -36 21 10 146 40 7 -36 35 22 148 24 1 -36 13 6 146 54 54 -35 10 55 8 45 31 61 85 -18 146 40 4 -35 14 4 147 9 41 -35 7 45 146 3 22 -35 21 42 147 45 51 -34 59 49 146 17 8 -33 57 25 8 46 11 61 87 -17 146 2 29 -34 0 31 146 31 44 -33 54 18 145 26 15 -34 8 0 147 7 26 -33 46 30 145 39 2 -32 43 51 8 46 51 61 90 -16 145 24 34 -32 46 53 145 53 27 -32 40 47 144 48 46 -32 54 15 146 28 44 -32 33 8 145 0 34 -31 30 10 8 47 31 60 92 -16 144 46 16 -31 33 9 145 14 49 -31 27 9 144 10 53 -31 40 23 145 49 42 -31 19 38 144 21 42 -30 16 20 8 48 11 60 94 -15 144 7 33 -30 19 16 144 35 48 -30 13 23 143 32 32 -30 26 22 145 10 19 -30 5 59 143 42 23 -29 2 19 8 48 51 59 97 -14 143 28 22 -29 5 12 143 56 21 -28 59 25 142 53 42 -29 12 9 144 30 32 -28 52 9 143 2 35 -27 48 3 8 49 31 59 99 -13 142 48 42 -27 50 53 143 16 25 -27 45 12 142 14 21 -27 57 43 143 50 18 -27 38 4 142 22 15 -26 33 30 8 50 11 58 101 -13 142 8 28 -26 36 16 142 35 58 -26 30 42 141 34 25 -26 42 59 143 9 34 -26 23 42 141 41 20 -25 18 37 8 50 51 57 103 -12 141 27 40 -25 21 20 141 54 57 -25 15 52 140 53 52 -25 27 54 142 28 17 -25 9 0 140 59 47 -24 3 21 8 51 31 57 105 -11 140 46 13 -24 6 1 141 13 19 -24 0 40 140 12 39 -24 12 27 141 46 25 -23 53 55 140 17 33 -22 47 39 8 52 11 56 107 -10 140 4 4 -22 50 15 140 31 0 -22 45 0 139 30 43 -22 56 33 141 3 54 -22 38 24 139 34 34 -21 31 26 8 52 52 55 108 -9 139 21 9 -21 34 0 139 47 56 -21 28 52 138 47 59 -21 40 9 140 20 40 -21 22 24 138 50 46 -20 14 41 8 53 32 54 110 -8 138 37 25 -20 17 11 139 4 4 -20 12 10 138 4 23 -20 23 11 139 36 39 -20 5 50 138 6 4 -18 57 18 8 54 12 53 112 -7 137 52 46 -18 59 44 138 19 20 -18 54 50 137 19 52 -19 5 36 138 51 47 -18 48 39 137 20 24 -17 39 14 8 54 52 52 113 -6 137 7 9 -17 41 36 137 33 38 -17 36 50 136 34 20 -17 47 19 138 5 58 -17 30 48 136 33 40 -16 20 24 8 55 32 51 115 -5 136 20 26 -16 22 42 136 46 52 -16 18 3 135 47 42 -16 28 15 137 19 9 -16 12 10 Uncertainty in time = +/- 16 secs Prediction of 2014 Jun 22.0
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