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Updated: 2009 NOV 28, 04:28 UT
Event Rank : 26
(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 2010 Jan 19 UT, the 19 km diameter asteroid (826) Henrika will occult a 9.9 mag star in the constellation Virgo for observers along a path across New South Wales at low altitude, near Sydney and across the south island of New Zealand.
In the case of an occultation, the combined light of the asteroid and the star will drop by 6.3 mag to 16.2 mag (the magnitude of the asteroid) for at most 1.1 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
147 45 6 -32 20 2 13 26 45 5 105 -36 148 34 0 -32 27 50 146 49 18 -32 10 17 151 49 56 -32 52 22 ... .. .. .. .. ..
151 34 56 -33 49 7 13 26 50 9 103 -35 152 7 16 -33 52 12 151 0 59 -33 45 35 154 34 33 -34 2 41 147 24 58 -33 15 42
154 16 52 -34 59 1 13 26 55 11 101 -35 154 43 21 -35 0 23 153 49 34 -34 57 26 156 48 45 -35 4 23 151 12 19 -34 44 28
156 29 24 -36 0 34 13 27 1 13 99 -34 156 52 41 -36 0 58 156 5 34 -36 0 1 158 45 5 -36 0 58 153 52 57 -35 54 22
158 24 27 -36 57 9 13 27 6 15 98 -33 158 45 42 -36 56 54 158 2 50 -36 57 17 160 29 19 -36 54 6 156 4 30 -36 56 1
160 7 40 -37 50 20 13 27 11 17 97 -32 160 27 27 -37 49 37 159 47 34 -37 50 59 162 4 43 -37 44 42 157 58 44 -37 52 44
161 42 11 -38 41 3 13 27 17 18 96 -31 162 0 54 -38 39 58 161 23 12 -38 42 4 163 33 19 -38 33 21 159 41 12 -38 46 6
163 10 0 -39 29 51 13 27 22 19 95 -30 163 27 52 -39 28 27 162 51 54 -39 31 11 164 56 31 -39 20 27 161 15 2 -39 37 1
164 32 28 -40 17 8 13 27 27 20 93 -29 164 49 41 -40 15 29 164 15 3 -40 18 43 166 15 17 -40 6 17 162 42 12 -40 26 2
165 50 33 -41 3 10 13 27 33 21 92 -29 166 7 14 -41 1 18 165 33 42 -41 4 59 167 30 21 -40 51 3 164 4 4 -41 13 33
167 5 0 -41 48 10 13 27 38 22 91 -28 167 21 14 -41 46 6 166 48 35 -41 50 10 168 42 17 -41 34 57 165 21 33 -41 59 50
168 16 20 -42 32 17 13 27 43 23 90 -27 168 32 13 -42 30 4 168 0 19 -42 34 29 169 51 33 -42 18 4 166 35 25 -42 45 6
169 25 1 -43 15 40 13 27 48 24 89 -26 169 40 36 -43 13 17 169 9 19 -43 18 1 170 58 30 -43 0 33 167 46 11 -43 29 31
170 31 25 -43 58 25 13 27 54 25 88 -25 170 46 44 -43 55 54 170 15 58 -44 0 55 172 3 26 -43 42 27 168 54 19 -44 13 12
171 35 48 -44 40 37 13 27 59 26 87 -24 171 50 54 -44 37 58 171 20 34 -44 43 15 173 6 36 -44 23 52 170 0 9 -44 56 16
172 38 25 -45 22 20 13 28 4 26 86 -24 172 53 21 -45 19 33 172 23 22 -45 25 5 174 8 12 -45 4 51 171 3 58 -45 38 47
Uncertainty in time = +/- 4 secs
Prediction of 2009 Nov 28.0
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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