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Updated: 2018 Jun 12, 23:48 UT
Event Rank : 71
(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 2018 Aug 05 UT, the 63 km diameter asteroid (795) Fini will occult a 12.2 mag star in the constellation Ara for observers along a somewhat uncertain path across New Zealand, passing near Hastings, Napier, Taupo and Coromandel.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.39 mag to 14.47 mag (the magnitude of the asteroid) for at most 8.9 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, astrometry for the asteroid kindly provided by Bill Owen, astrometry for the asteroid kindly provided by the IAU Minor Planet Center. This work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
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 UCAC4-202-150088 by 795 Fini on 2018 Aug 5
Centre Star Star Sun Path Limits Error Limits Alt
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 Crn
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
175 6 58 -34 0 0 9 25 17 72 201 -46 175 27 54 174 46 3 175 56 28 174 17 37 -0.16
175 20 9 -35 0 0 9 25 1 73 202 -46 175 41 21 174 58 59 176 10 18 174 30 11 -0.16
175 33 48 -36 0 0 9 24 46 74 204 -46 175 55 17 175 12 21 176 24 36 174 43 11 -0.16
175 47 55 -37 0 0 9 24 31 75 206 -46 176 9 41 175 26 11 176 39 24 174 56 37 -0.16
176 2 32 -38 0 0 9 24 15 76 208 -46 176 24 36 175 40 29 176 54 44 175 10 31 -0.16
176 17 40 -39 0 0 9 23 59 76 211 -46 176 40 3 175 55 18 177 10 38 175 24 53 -0.16
176 33 21 -40 0 0 9 23 44 77 213 -46 176 56 5 176 10 39 177 27 7 175 39 47 -0.16
176 49 36 -41 0 0 9 23 28 78 217 -45 177 12 42 176 26 33 177 44 14 175 55 12 -0.16
177 6 29 -42 0 0 9 23 12 79 220 -45 177 29 57 176 43 3 178 2 0 176 11 12 -0.16
Uncertainty in time = +/- 6 secs
Prediction of 2018 Jun 12.0
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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