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Updated: 2021 JAN 31, 18:42 UT
Event Rank : 99
(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 2021 Mar 16 UT, the 187.4 km diameter asteroid (41) Daphne will occult a 12.3 mag star in the constellation Orion for observers along a broad path that includes most New Zealand, all but the south-west of the South Island and the north-west of the North Island north of about Auckland.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.91 mag to 12.63 mag (the magnitude of the asteroid) for at most 15.0 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, inparticular 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 488-021007 by 41 Daphne #1 on 2021 Mar 16
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
170 45 16 -48 0 0 9 29 40.9 28 323 -25 173 16 4 168 20 10 174 6 17 167 34 15 1.55
171 15 23 -47 0 0 9 29 49.3 28 322 -26 173 44 34 168 51 53 174 34 15 168 6 30 1.55
171 47 6 -46 0 0 9 29 57.9 29 321 -27 174 14 52 169 25 1 175 4 6 168 40 6 1.56
172 20 24 -45 0 0 9 30 6.7 29 320 -27 174 46 58 169 59 33 175 35 48 169 15 2 1.56
172 55 18 -44 0 0 9 30 15.7 30 319 -28 175 20 51 170 35 30 176 9 23 169 51 20 1.56
173 31 48 -43 0 0 9 30 25.0 30 318 -29 175 56 33 171 12 52 176 44 50 170 29 0 1.56
174 9 55 -42 0 0 9 30 34.5 31 317 -30 176 34 4 171 51 41 177 22 11 171 8 3 1.57
174 49 42 -41 0 0 9 30 44.2 31 316 -31 177 13 27 172 31 58 178 1 28 171 48 31 1.57
175 31 10 -40 0 0 9 30 54.1 31 315 -32 177 54 44 173 13 46 178 42 43 172 30 26 1.57
176 14 23 -39 0 0 9 31 4.2 32 314 -33 178 37 58 173 57 6 179 26 1 173 13 51 1.57
176 59 24 -38 0 0 9 31 14.6 32 312 -34 179 23 14 174 42 4 -179 48 35 173 58 49 1.58
177 46 17 -37 0 0 9 31 25.2 32 311 -36 -179 49 22 175 28 41 -179 0 58 174 45 24 1.58
178 35 9 -36 0 0 9 31 36.0 32 310 -37 -178 59 45 176 17 4 -178 11 2 175 33 40 1.58
179 26 5 -35 0 0 9 31 47.0 32 309 -38 -178 7 47 177 7 16 -177 18 39 176 23 42 1.59
Uncertainty in time = +/- 2 secs
Prediction of 2021 Jan 31.0
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