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Updated: 2015 Sep 18, 22:27 UT
Event Rank : 85
(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 2015 Oct 14 UT, the 44 km diameter asteroid (118) Peitho will occult a 12.2 mag star in the constellation Taurus for observers along a path across central Australia and northern Queensland.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.8 mag to 12.3 mag (the magnitude of the asteroid) for at most 14.6 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 2UCAC 39436242 by 118 Peitho on 2015 Oct 14
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
133 26 32 -27 26 27 13 18 18 6 62 -48 131 13 46 -28 20 17 134 59 51 -26 48 58 ... .. .. .. .. .. 136 30 1 -26 13 5
136 26 43 -25 7 25 13 18 48 9 61 -51 135 18 2 -25 34 36 137 27 42 -24 43 28 133 39 37 -26 13 53 138 33 39 -24 17 46
138 18 31 -23 17 44 13 19 18 12 60 -54 137 25 49 -23 38 12 139 7 30 -22 58 51 136 16 13 -24 5 25 140 2 22 -22 37 51
139 40 39 -21 41 12 13 19 48 14 60 -56 138 56 1 -21 58 14 140 22 59 -21 25 8 137 58 46 -22 20 14 141 11 12 -21 6 59
140 45 4 -20 12 44 13 20 18 15 59 -58 140 5 27 -20 27 37 141 23 4 -19 58 32 139 15 26 -20 46 33 142 6 46 -19 42 19
141 37 21 -18 49 57 13 20 48 17 59 -59 141 1 13 -19 3 20 142 12 15 -18 37 6 140 16 2 -19 20 11 142 52 40 -18 22 18
142 20 38 -17 31 28 13 21 18 18 59 -61 141 47 6 -17 43 44 142 53 12 -17 19 38 141 5 24 -17 59 5 143 31 5 -17 5 57
142 56 55 -16 16 25 13 21 48 19 59 -62 142 25 23 -16 27 49 143 27 39 -16 5 23 141 46 22 -16 42 0 144 3 31 -15 52 35
143 27 32 -15 4 12 13 22 18 21 59 -64 142 57 36 -15 14 53 143 56 46 -14 53 49 142 20 41 -15 28 9 144 31 1 -14 41 44
143 53 26 -13 54 22 13 22 48 22 59 -65 143 24 49 -14 4 29 144 21 27 -13 44 31 142 49 37 -14 16 59 144 54 20 -13 33 2
144 15 20 -12 46 35 13 23 19 23 60 -66 143 47 48 -12 56 13 144 42 19 -12 37 11 143 14 2 -13 8 6 145 14 4 -12 26 13
144 33 46 -11 40 36 13 23 49 23 60 -67 144 7 10 -11 49 49 144 59 53 -11 31 36 143 34 35 -12 1 10 145 30 39 -11 21 4
144 49 10 -10 36 12 13 24 19 24 60 -69 144 23 21 -10 45 4 145 14 32 -10 27 32 143 51 48 -10 55 58 145 44 27 -10 17 23
Uncertainty in time = +/- 9 secs
Prediction of 2015 Sep 19.0
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