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Updated: 2014 Jul 08, 16:45 UT
Event Rank : 17
(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 15 UT, the 20 km diameter asteroid (1236) Thais will occult a 10.7 mag star in the constellation Grus for observers along a large uncertainty path across northern and western Queensland and north-western South Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.7 mag to 14.4 mag (the magnitude of the asteroid) for at most 3.5 seconds.
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 TYC 7502-00094-1 by 1236 Thais on 2014 Jul 15
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
143 58 28 -10 0 0 14 44 25 48 137 -78 143 51 14 144 5 41 142 53 37 145 2 21
143 39 25 -11 0 0 14 44 43 49 136 -79 143 32 8 143 46 42 142 34 9 144 43 44
143 19 22 -12 0 0 14 45 2 49 135 -80 143 12 2 143 26 42 142 13 37 144 24 7
142 58 16 -13 0 0 14 45 20 50 134 -81 142 50 53 143 5 39 141 52 0 144 3 31
142 36 6 -14 0 0 14 45 39 50 133 -82 142 28 38 142 43 32 141 29 16 143 41 52
142 12 48 -15 0 0 14 45 59 51 132 -83 142 5 17 142 20 19 141 5 22 143 19 10
141 48 22 -16 0 0 14 46 18 51 131 -84 141 40 46 141 55 56 140 40 16 142 55 21
141 22 43 -17 0 0 14 46 38 52 130 -85 141 15 3 141 30 23 140 13 55 142 30 23
140 55 51 -18 0 0 14 46 58 52 129 -86 140 48 5 141 3 35 139 46 17 142 4 14
140 27 40 -19 0 0 14 47 18 52 127 -87 140 19 50 140 35 30 139 17 16 141 36 51
139 58 9 -20 0 0 14 47 38 53 126 -88 139 50 12 140 6 5 138 46 51 141 8 10
139 27 12 -21 0 0 14 47 58 53 125 -88 139 19 9 139 35 14 138 14 57 140 38 8
138 0 0 -23 35 22 14 48 52 53 122 -87 -23 21 19 -23 49 20 -21 27 10 -25 36 55
137 0 0 -25 12 9 14 49 27 53 120 -85 -24 58 48 -25 25 26 -23 10 37 -27 8 2
136 0 0 -26 41 57 14 49 59 53 118 -84 -26 29 12 -26 54 39 -24 46 6 -28 32 53
135 0 0 -28 5 34 14 50 30 53 116 -82 -27 53 20 -28 17 45 -26 14 40 -29 52 10
134 0 0 -29 23 42 14 50 59 53 114 -81 -29 11 56 -29 35 26 -27 37 9 -31 6 26
133 0 0 -30 36 54 14 51 26 53 113 -79 -30 25 32 -30 48 13 -28 54 11 -32 16 10
132 0 0 -31 45 36 14 51 53 53 112 -78 -31 34 37 -31 56 34 -30 6 20 -33 21 46
131 0 0 -32 50 15 14 52 18 52 110 -77 -32 39 35 -33 0 52 -31 14 5 -34 23 35
130 0 0 -33 51 9 14 52 42 52 109 -76 -33 40 47 -34 1 28 -32 17 47 -35 21 54
129 0 0 -34 48 36 14 53 4 52 108 -74 -34 38 32 -34 58 39 -33 17 48 -36 17 1
128 0 0 -35 42 53 14 53 26 51 108 -73 -35 33 4 -35 52 41 -34 14 26 -37 9 8
127 0 0 -36 34 13 14 53 47 51 107 -72 -36 24 38 -36 43 47 -35 7 55 -37 58 28
126 0 0 -37 22 48 14 54 8 50 106 -71 -37 13 26 -37 32 9 -35 58 28 -38 45 12
125 0 0 -38 8 49 14 54 27 50 106 -70 -37 59 39 -38 17 58 -36 46 19 -39 29 30
Uncertainty in time = +/- 15 secs
Prediction of 2014 Jul 8.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
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[Reporting Details]
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