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Updated: 2013 SEP 14, 22:06 UT
Event Rank : 59
(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 2013 Oct 06 UT, the 93 km diameter asteroid (983) Gunila will occult a 11.1 mag star in the constellation Triangulum for observers along a narrow path roughly following the eastern coast of New Zealand, at low elevation.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.7 mag to 14.8 mag (the magnitude of the asteroid) for at most 7.3 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.
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
164 38 47 -51 0 0 12 20 20 10 21 -33 163 24 55 165 53 14 160 50 8 168 33 20
165 41 11 -50 0 0 12 20 18 11 21 -35 164 28 21 166 54 39 161 55 46 169 32 41
166 43 50 -49 0 0 12 20 14 12 20 -36 165 31 54 167 56 24 163 1 19 170 32 34
167 46 47 -48 0 0 12 20 11 13 19 -37 166 35 41 168 58 32 164 6 55 171 33 2
168 50 8 -47 0 0 12 20 7 15 18 -38 167 39 46 170 1 9 165 12 37 172 34 10
169 53 56 -46 0 0 12 20 3 16 17 -39 168 44 14 171 4 19 166 18 32 173 36 3
170 58 16 -45 0 0 12 19 58 17 16 -40 169 49 9 172 8 7 167 24 44 174 38 44
172 3 14 -44 0 0 12 19 53 18 15 -41 170 54 36 173 12 36 168 31 18 175 42 18
173 8 54 -43 0 0 12 19 48 19 15 -42 172 0 41 174 17 53 169 38 20 176 46 49
174 15 21 -42 0 0 12 19 42 20 14 -43 173 7 28 175 24 1 170 45 55 177 52 23
175 22 41 -41 0 0 12 19 36 22 13 -44 174 15 3 176 31 6 171 54 7 178 59 5
176 30 57 -40 0 0 12 19 29 23 12 -45 175 23 30 177 39 14 173 3 3 -179 52 59
177 40 17 -39 0 0 12 19 22 24 11 -46 176 32 56 178 48 30 174 12 47 -178 43 43
178 50 47 -38 0 0 12 19 15 25 10 -46 177 43 26 179 59 1 175 23 25 -177 33 1
-179 57 28 -37 0 0 12 19 7 26 9 -47 178 55 7 -178 49 7 176 35 4 -176 20 45
-178 44 20 -36 0 0 12 18 59 27 8 -48 -179 51 55 -177 35 46 177 47 50 -175 6 47
Uncertainty in time = +/- 8 secs
Prediction of 2013 Sep 15.0
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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