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Updated: 2020 APR 06, 05:13 UT
Event Rank : 100
(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 2020 Jul 24 UT, the 192.8 km diameter asteroid (375) Ursula will occult a 12.0 mag star in the constellation Pisces for observers along a broad path including most of the South Island of of New Zealand.
In the case of an occultation, the combined light of the asteroid and the star will drop by 0.80 mag to 12.12 mag (the magnitude of the asteroid) for at most 35.0 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 450-138068 by 375 Ursula on 2020 Jul 24
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 36 47 -48 0 0 13 40 4.7 31 47 -59 172 25 39 168 45 12 173 10 3 167 58 4 -0.97
170 51 56 -47 0 0 13 40 19.5 32 47 -60 172 38 22 169 2 56 173 21 48 168 16 54 -0.97
171 4 49 -46 0 0 13 40 34.6 33 47 -61 172 49 1 169 18 12 173 31 33 168 33 13 -0.97
171 15 37 -45 0 0 13 40 50.0 34 48 -62 172 57 42 169 31 12 173 39 25 168 47 10 -0.97
171 24 25 -44 0 0 13 41 5.7 35 48 -63 173 4 34 169 42 4 173 45 30 168 58 56 -0.97
171 31 23 -43 0 0 13 41 21.6 35 48 -63 173 9 43 169 50 56 173 49 55 169 8 37 -0.97
171 36 36 -42 0 0 13 41 37.7 36 49 -64 173 13 14 169 57 56 173 52 45 169 16 23 -0.97
171 40 9 -41 0 0 13 41 54.1 37 49 -65 173 15 13 170 3 9 173 54 6 169 22 18 -0.97
171 42 8 -40 0 0 13 42 10.8 38 50 -66 173 15 44 170 6 41 173 54 1 169 26 30 -0.96
171 42 38 -39 0 0 13 42 27.7 38 50 -66 173 14 51 170 8 37 173 52 35 169 29 4 -0.96
171 41 43 -38 0 0 13 42 44.9 39 51 -67 173 12 38 170 9 2 173 49 51 169 30 3 0.96
171 39 26 -37 0 0 13 43 2.3 40 51 -68 173 9 9 170 8 0 173 45 52 169 29 34 0.96
171 35 50 -36 0 0 13 43 19.9 40 52 -69 173 4 26 170 5 35 173 40 42 169 27 38 0.96
171 30 59 -35 0 0 13 43 37.7 41 53 -69 172 58 32 170 1 49 173 34 23 169 24 21 0.96
171 24 56 -34 0 0 13 43 55.8 42 53 -70 172 51 30 169 56 47 173 26 57 169 19 44 0.96
171 17 42 -33 0 0 13 44 14.0 42 54 -71 172 43 22 169 50 30 173 18 27 169 13 51 0.96
171 9 21 -32 0 0 13 44 32.5 43 55 -71 172 34 10 169 43 0 173 8 54 169 6 44 0.96
170 59 53 -31 0 0 13 44 51.2 43 56 -72 172 23 55 169 34 21 172 58 20 168 58 25 0.95
170 49 21 -30 0 0 13 45 10.0 44 57 -73 172 12 39 169 24 34 172 46 47 168 48 57 0.95
170 37 46 -29 0 0 13 45 29.1 44 58 -73 172 0 24 169 13 40 172 34 15 168 38 21 0.95
170 25 10 -28 0 0 13 45 48.3 45 58 -74 171 47 11 169 1 42 172 20 47 168 26 38 0.95
170 11 33 -27 0 0 13 46 7.8 45 59 -74 171 33 0 168 48 39 172 6 23 168 13 50 0.95
169 56 56 -26 0 0 13 46 27.3 45 60 -75 171 17 53 168 34 34 171 51 3 167 59 58 0.94
169 41 21 -25 0 0 13 46 47.1 46 62 -75 171 1 50 168 19 27 171 34 49 167 45 3 0.94
169 24 48 -24 0 0 13 47 7.0 46 63 -76 170 44 52 168 3 19 171 17 41 167 29 6 0.94
169 7 18 -23 0 0 13 47 27.1 46 64 -76 170 27 0 167 46 11 170 59 39 167 12 7 0.94
168 48 50 -22 0 0 13 47 47.3 46 65 -77 170 8 13 167 28 2 170 40 45 166 54 6 0.94
168 29 25 -21 0 0 13 48 7.7 47 66 -77 169 48 32 167 8 54 170 20 57 166 35 5 0.93
168 9 4 -20 0 0 13 48 28.2 47 67 -77 169 27 57 166 48 46 170 0 16 166 15 2 0.93
167 47 46 -19 0 0 13 48 48.8 47 68 -77 169 6 28 166 27 39 169 38 42 165 53 59 0.93
167 25 31 -18 0 0 13 49 9.5 47 69 -77 168 44 5 166 5 31 169 16 15 165 31 54 0.93
167 2 18 -17 0 0 13 49 30.4 47 71 -77 168 20 47 165 42 23 168 52 55 165 8 48 0.93
166 38 8 -16 0 0 13 49 51.4 47 72 -77 167 56 33 165 18 15 168 28 40 164 44 40 0.92
166 12 59 -15 0 0 13 50 12.5 47 73 -77 167 31 25 164 53 5 168 3 31 164 19 29 0.92
165 46 51 -14 0 0 13 50 33.6 47 74 -77 167 5 19 164 26 52 167 37 27 163 53 15 0.92
165 19 42 -13 0 0 13 50 54.9 47 76 -77 166 38 17 163 59 37 167 10 26 163 25 56 0.92
164 51 33 -12 0 0 13 51 16.3 47 77 -77 166 10 16 163 31 17 166 42 28 162 57 32 0.91
164 22 21 -11 0 0 13 51 37.7 47 78 -76 165 41 15 163 1 52 166 13 32 162 28 0 0.91
163 52 5 -10 0 0 13 51 59.2 47 79 -76 165 11 14 162 31 19 165 43 36 161 57 20 0.91
Uncertainty in time = +/- 8 secs
Prediction of 2020 Apr 6.0
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