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Updated: 2015 FEB 10, 22:55 UT
Event Rank : 30
(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 2015 Mar 28 UT, the 29 km diameter asteroid (378) Holmia will occult a 11.4 mag star in the constellation Cancer for observers along a path across Australia, from just south of Sydney across north-eastern New South Wales to Walgett, then across western Queensland to Karumba.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.3 mag to 14.7 mag (the magnitude of the asteroid) for at most 7.4 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, 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 Limit1 Path Limit2 Error Limit1 Error Limit2
E. Longitude Latitude U.T. Alt Az Alt
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
171 24 42 -51 7 44 12 40 59 17 305 -42 171 7 50 -51 9 22 171 41 41 -51 6 7 169 54 4 -51 16 58 172 59 8 -50 59 15
166 29 53 -48 17 33 12 41 38 21 309 -45 166 15 25 -48 19 22 166 44 25 -48 15 45 165 11 43 -48 27 41 167 50 8 -48 7 55
162 49 45 -45 44 22 12 42 17 24 311 -47 162 36 39 -45 46 15 163 2 53 -45 42 30 161 38 47 -45 54 48 164 2 5 -45 34 19
159 53 33 -43 22 45 12 42 57 27 313 -49 159 41 22 -43 24 39 160 5 45 -43 20 52 158 47 28 -43 33 16 161 0 38 -43 12 33
157 26 29 -41 9 46 12 43 36 30 314 -50 157 14 59 -41 11 40 157 38 0 -41 7 52 156 24 1 -41 20 15 158 29 45 -40 59 32
155 20 12 -39 3 35 12 44 15 33 315 -52 155 9 13 -39 5 28 155 31 12 -39 1 42 154 20 32 -39 14 1 156 20 31 -38 53 23
153 29 28 -37 2 57 12 44 55 35 316 -53 153 18 55 -37 4 50 153 40 2 -37 1 5 152 32 5 -37 13 18 154 27 25 -36 52 49
151 50 49 -35 6 59 12 45 34 37 317 -54 151 40 37 -35 8 51 152 1 2 -35 5 8 150 55 18 -35 17 15 152 46 48 -34 56 55
150 21 47 -33 14 59 12 46 13 39 317 -55 150 11 53 -33 16 50 150 31 42 -33 13 9 149 27 52 -33 25 9 151 16 8 -33 5 0
149 0 36 -31 26 25 12 46 53 41 317 -56 148 50 57 -31 28 15 149 10 16 -31 24 35 148 8 2 -31 36 29 149 53 32 -31 16 31
147 45 55 -29 40 51 12 47 32 43 317 -56 147 36 29 -29 42 40 147 55 22 -29 39 2 146 54 32 -29 50 49 148 37 38 -29 31 1
146 36 42 -27 57 55 12 48 11 45 317 -57 146 27 28 -27 59 43 146 45 58 -27 56 7 145 46 22 -28 7 49 147 27 22 -27 48 10
145 32 10 -26 17 20 12 48 51 47 317 -58 145 23 5 -26 19 7 145 41 15 -26 15 33 144 42 44 -26 27 9 146 21 53 -26 7 39
144 31 38 -24 38 51 12 49 30 49 317 -58 144 22 42 -24 40 38 144 40 34 -24 37 5 143 43 0 -24 48 35 145 20 32 -24 29 14
143 34 36 -23 2 15 12 50 9 50 316 -58 143 25 48 -23 4 1 143 43 24 -23 0 30 142 46 41 -23 11 55 144 22 46 -22 52 42
142 40 37 -21 27 20 12 50 49 52 316 -59 142 31 56 -21 29 6 142 49 18 -21 25 36 141 53 21 -21 36 57 143 28 8 -21 17 51
141 49 20 -19 53 58 12 51 28 53 315 -59 141 40 46 -19 55 42 141 57 55 -19 52 14 141 2 38 -20 3 31 142 36 17 -19 44 32
141 0 27 -18 21 58 12 52 7 55 315 -59 140 51 59 -18 23 42 141 8 57 -18 20 15 140 14 16 -18 31 28 141 46 53 -18 12 35
140 13 43 -16 51 14 12 52 47 56 314 -59 140 5 19 -16 52 58 140 22 7 -16 49 31 139 27 58 -17 0 41 140 59 41 -16 41 54
139 28 54 -15 21 39 12 53 26 58 313 -59 139 20 35 -15 23 22 139 37 14 -15 19 56 138 43 33 -15 31 3 140 14 27 -15 12 21
138 45 49 -13 53 5 12 54 5 59 312 -59 138 37 33 -13 54 48 138 54 5 -13 51 23 138 0 49 -14 2 27 139 31 1 -13 43 49
138 4 18 -12 25 28 12 54 45 61 311 -59 137 56 6 -12 27 10 138 12 30 -12 23 46 137 19 37 -12 34 48 138 49 11 -12 16 14
137 24 13 -10 58 43 12 55 24 62 310 -59 137 16 4 -11 0 24 137 32 22 -10 57 1 136 39 48 -11 8 1 138 8 49 -10 49 30
136 45 26 - 9 32 43 12 56 3 63 308 -59 136 37 19 - 9 34 25 136 53 32 - 9 31 2 136 1 16 - 9 42 0 137 29 47 - 9 23 32
Uncertainty in time = +/- 18 secs
Prediction of 2015 Feb 11.0
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