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Updated: 2021 Dec 31, 01:54 UT
Event Rank : 98
(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 2022 Feb 28 UT, the 75 km diameter asteroid (331) Etheridgea will occult a 12.1 mag star in the constellation Gemini for observers along a path across eastern West Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.1 mag to 15.17 mag (the magnitude of the asteroid) for at most 24.6 seconds.
This update is based on, 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 UCAC4-603-036494 by 331 Etheridgea on 2022 Feb 28
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
128 17 22 -37 0 0 12 52 28.9 20 343 -31 127 51 2 128 43 44 127 31 50 129 3 3 -0.15
127 59 20 -36 0 0 12 52 15.6 21 343 -31 127 33 23 128 25 20 127 14 27 128 44 22 -0.16
127 42 5 -35 0 0 12 52 1.6 22 343 -31 127 16 29 128 7 43 126 57 49 128 26 29 -0.16
127 25 34 -34 0 0 12 51 47.0 23 343 -32 127 0 19 127 50 52 126 41 54 128 9 23 -0.16
127 9 46 -33 0 0 12 51 31.8 25 344 -32 126 44 50 127 34 44 126 26 39 127 53 1 -0.16
126 54 38 -32 0 0 12 51 15.9 26 344 -33 126 30 0 127 19 17 126 12 2 127 37 21 -0.16
126 40 8 -31 0 0 12 50 59.5 27 344 -33 126 15 48 127 4 30 125 58 3 127 22 20 -0.16
126 26 15 -30 0 0 12 50 42.5 28 344 -33 126 2 11 126 50 20 125 44 38 127 7 58 -0.16
126 12 56 -29 0 0 12 50 25.0 29 344 -34 125 49 9 126 36 46 125 31 47 126 54 13 -0.16
126 0 12 -28 0 0 12 50 6.8 30 344 -34 125 36 39 126 23 46 125 19 28 126 41 2 -0.16
125 47 59 -27 0 0 12 49 48.1 31 344 -34 125 24 40 126 11 19 125 7 39 126 28 24 -0.16
125 36 16 -26 0 0 12 49 28.8 32 344 -35 125 13 11 125 59 23 124 56 20 126 16 18 -0.16
125 25 3 -25 0 0 12 49 9.0 33 345 -35 125 2 10 125 47 57 124 45 29 126 4 42 -0.16
125 14 17 -24 0 0 12 48 48.6 34 345 -35 124 51 37 125 36 59 124 35 4 125 53 36 -0.16
125 3 59 -23 0 0 12 48 27.7 35 345 -36 124 41 30 125 26 29 124 25 5 125 42 57 -0.16
124 54 6 -22 0 0 12 48 6.2 36 345 -36 124 31 48 125 16 25 124 15 31 125 32 46 -0.16
124 44 37 -21 0 0 12 47 44.2 37 345 -36 124 22 30 125 6 47 124 6 20 125 22 59 -0.16
124 35 32 -20 0 0 12 47 21.7 38 345 -36 124 13 34 124 57 32 123 57 32 125 13 38 -0.16
124 26 50 -19 0 0 12 46 58.7 39 345 -37 124 5 1 124 48 41 123 49 6 125 4 39 -0.16
124 18 29 -18 0 0 12 46 35.2 40 345 -37 123 56 49 124 40 11 123 41 0 124 56 4 -0.16
124 10 30 -17 0 0 12 46 11.2 41 345 -37 123 48 57 124 32 3 123 33 14 124 47 50 -0.15
124 2 50 -16 0 0 12 45 46.7 42 345 -37 123 41 25 124 24 16 123 25 47 124 39 57 -0.15
123 55 29 -15 0 0 12 45 21.7 43 345 -37 123 34 11 124 16 48 123 18 38 124 32 24 -0.15
123 48 26 -14 0 0 12 44 56.2 44 345 -38 123 27 15 124 9 38 123 11 46 124 25 9 -0.15
123 41 41 -13 0 0 12 44 30.3 45 345 -38 123 20 35 124 2 47 123 5 12 124 18 13 -0.15
123 35 12 -12 0 0 12 44 3.9 46 345 -38 123 14 12 123 56 13 122 58 53 124 11 35 -0.15
123 28 59 -11 0 0 12 43 37.1 47 345 -38 123 8 5 123 49 55 122 52 49 124 5 13 -0.15
123 23 2 -10 0 0 12 43 9.8 48 345 -38 123 2 13 123 43 53 122 47 0 123 59 8 -0.15
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