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Updated: 2015 AUG 20, 06:18 UT
Event Rank : 60
(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 Sep 12 UT, the 59 km diameter asteroid (60) Echo will occult a 11.5 mag star in the constellation Sagittarius for observers along a path across Australia, across eastern Northern Territory and eastern South Australia to Adelaide.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.6 mag to 12.8 mag (the magnitude of the asteroid) for at most 30.4 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.
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
135 33 40 -10 0 0 11 58 35 74 240 -46 135 17 3 135 50 19 134 42 32 136 24 59
135 32 31 -11 0 0 11 59 34 74 243 -46 135 15 49 135 49 13 134 41 10 136 24 2
135 31 44 -12 0 0 12 0 32 74 247 -46 135 14 58 135 48 31 134 40 10 136 23 30
135 31 21 -13 0 0 12 1 30 75 250 -46 135 14 30 135 48 13 134 39 32 136 23 22
135 31 23 -14 0 0 12 2 29 75 254 -47 135 14 27 135 48 21 134 39 17 136 23 41
135 31 52 -15 0 0 12 3 27 75 258 -47 135 14 50 135 48 55 134 39 28 136 24 28
135 32 48 -16 0 0 12 4 26 75 261 -47 135 15 40 135 49 58 134 40 6 136 25 44
135 34 13 -17 0 0 12 5 25 74 265 -47 135 16 58 135 51 29 134 41 11 136 27 30
135 36 9 -18 0 0 12 6 24 74 268 -47 135 18 47 135 53 32 134 42 45 136 29 47
135 38 37 -19 0 0 12 7 22 74 272 -47 135 21 7 135 56 8 134 44 49 136 32 39
135 41 38 -20 0 0 12 8 21 74 275 -47 135 24 0 135 59 17 134 47 26 136 36 6
135 45 15 -21 0 0 12 9 20 73 278 -47 135 27 28 136 3 3 134 50 36 136 40 9
135 49 28 -22 0 0 12 10 19 73 281 -47 135 31 33 136 7 26 134 54 22 136 44 52
135 54 21 -23 0 0 12 11 18 72 284 -47 135 36 16 136 12 28 134 58 45 136 50 15
135 59 56 -24 0 0 12 12 17 72 286 -47 135 41 40 136 18 13 135 3 47 136 56 22
136 6 13 -25 0 0 12 13 16 71 289 -47 135 47 46 136 24 41 135 9 31 137 3 14
136 13 16 -26 0 0 12 14 14 70 291 -47 135 54 38 136 31 56 135 15 59 137 10 53
136 21 7 -27 0 0 12 15 13 70 293 -46 136 2 17 136 40 0 135 23 12 137 19 23
136 29 49 -28 0 0 12 16 12 69 295 -46 136 10 46 136 48 55 135 31 14 137 28 47
136 39 25 -29 0 0 12 17 10 68 297 -46 136 20 7 136 58 45 135 40 7 137 39 6
136 49 57 -30 0 0 12 18 8 67 298 -46 136 30 25 137 9 32 135 49 54 137 50 24
137 1 29 -31 0 0 12 19 6 67 299 -46 136 41 41 137 21 20 136 0 39 138 2 46
137 14 5 -32 0 0 12 20 4 66 301 -46 136 54 0 137 34 12 136 12 23 138 16 13
137 27 48 -33 0 0 12 21 2 65 302 -46 137 7 25 137 48 13 136 25 12 138 30 52
137 42 42 -34 0 0 12 22 0 64 303 -45 137 22 1 138 3 26 136 39 9 138 46 45
137 58 52 -35 0 0 12 22 57 63 304 -45 137 37 51 138 19 56 136 54 19 139 3 57
138 16 22 -36 0 0 12 23 55 62 305 -45 137 55 0 138 37 48 137 10 44 139 22 35
138 35 19 -37 0 0 12 24 52 61 305 -45 138 13 34 138 57 7 137 28 32 139 42 42
138 55 46 -38 0 0 12 25 49 60 306 -44 138 33 38 139 17 59 137 47 46 140 4 26
139 17 52 -39 0 0 12 26 45 59 307 -44 138 55 18 139 40 31 138 8 34 140 27 53
139 41 43 -40 0 0 12 27 42 58 307 -44 139 18 41 140 4 50 138 31 1 140 53 10
140 7 26 -41 0 0 12 28 38 57 307 -43 139 43 54 140 31 2 138 55 14 141 20 26
140 35 9 -42 0 0 12 29 34 56 308 -43 140 11 6 140 59 18 139 21 22 141 49 49
141 5 3 -43 0 0 12 30 29 55 308 -43 140 40 26 141 29 46 139 49 32 142 21 31
141 37 17 -44 0 0 12 31 25 54 308 -42 141 12 4 142 2 37 140 19 56 142 55 41
Latitude Latitude Latitude Latitude
142 0 0 -44 39 42 12 32 1 53 308 -42 -45 23 4 -43 55 23 -46 50 29 -42 19 46
143 0 0 -46 15 52 12 33 29 52 308 -42 -46 56 0 -45 34 58 -48 17 16 -44 7 16
144 0 0 -47 41 26 12 34 47 50 308 -41 -48 18 57 -47 3 18 -49 35 11 -45 41 52
145 0 0 -48 58 21 12 35 57 49 307 -40 -49 33 42 -48 22 30 -50 45 43 -47 6 12
Uncertainty in time = +/- 32 secs
Prediction of 2015 Aug 20.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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