|
|
Updated: 2009 APR 04, 03:23 UT
Event Rank : 94
(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 2009 May 06 UT, the 127 km diameter asteroid (426) Hippo will occult a 11.3 mag star in the constellation Corona Australis for observers along a path from just east of Darwin to Eucla in Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.2 mag to 13.4 mag (the magnitude of the asteroid) for at most 55.7 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 Limits Error Limits
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
135 42 12 - 7 0 0 18 45 17 55 174 -33 135 5 40 136 18 39 134 31 58 136 52 6
135 27 23 - 8 0 0 18 45 57 56 173 -33 134 50 46 136 3 55 134 16 59 136 37 27
135 12 17 - 9 0 0 18 46 38 57 173 -33 134 35 33 135 48 55 134 1 40 136 22 33
134 56 54 -10 0 0 18 47 19 58 173 -34 134 20 3 135 33 39 133 46 4 136 7 23
134 41 13 -11 0 0 18 48 1 59 173 -34 134 4 15 135 18 6 133 30 8 135 51 57
134 25 15 -12 0 0 18 48 44 60 172 -34 133 48 8 135 2 16 133 13 54 135 36 14
134 9 0 -13 0 0 18 49 26 61 172 -35 133 31 44 134 46 10 132 57 21 135 20 16
133 52 27 -14 0 0 18 50 9 62 171 -35 133 15 1 134 29 46 132 40 29 135 4 2
133 35 35 -15 0 0 18 50 53 63 171 -35 132 57 59 134 13 6 132 23 18 134 47 31
133 18 26 -16 0 0 18 51 37 64 170 -35 132 40 38 133 56 8 132 5 46 134 30 43
133 0 59 -17 0 0 18 52 21 65 170 -36 132 22 59 133 38 52 131 47 55 134 13 38
132 43 12 -18 0 0 18 53 6 66 169 -36 132 4 59 133 21 19 131 29 44 133 56 17
132 25 7 -19 0 0 18 53 51 67 169 -36 131 46 41 133 3 28 131 11 12 133 38 38
132 6 43 -20 0 0 18 54 36 68 168 -36 131 28 1 132 45 18 130 52 19 133 20 42
131 47 59 -21 0 0 18 55 22 69 167 -37 131 9 2 132 26 50 130 33 5 133 2 28
131 28 56 -22 0 0 18 56 8 70 166 -37 130 49 42 132 8 3 130 13 30 132 43 56
131 9 31 -23 0 0 18 56 55 70 165 -37 130 30 0 131 48 56 129 53 32 132 25 5
130 49 47 -24 0 0 18 57 41 71 164 -37 130 9 56 131 29 29 129 33 11 132 5 55
130 29 40 -25 0 0 18 58 28 72 163 -37 129 49 31 131 9 43 129 12 27 131 46 26
130 9 12 -26 0 0 18 59 15 73 162 -38 129 28 42 130 49 35 128 51 19 131 26 38
129 48 22 -27 0 0 19 0 3 74 160 -38 129 7 29 130 29 6 128 29 46 131 6 28
129 27 8 -28 0 0 19 0 50 75 159 -38 128 45 52 130 8 15 128 7 48 130 45 58
129 5 30 -29 0 0 19 1 38 76 157 -38 128 23 51 129 47 2 127 45 23 130 25 7
128 43 28 -30 0 0 19 2 26 77 155 -38 128 1 23 129 25 25 127 22 32 130 3 53
128 21 0 -31 0 0 19 3 15 77 152 -38 127 38 28 129 3 24 126 59 12 129 42 16
127 58 6 -32 0 0 19 4 3 78 149 -38 127 15 6 128 40 58 126 35 23 129 20 16
127 34 44 -33 0 0 19 4 52 79 146 -38 126 51 14 128 18 6 126 11 4 128 57 51
127 10 54 -34 0 0 19 5 41 80 142 -38 126 26 53 127 54 47 125 46 14 128 35 0
126 46 34 -35 0 0 19 6 30 80 138 -39 126 2 0 127 30 59 125 20 50 128 11 43
126 21 43 -36 0 0 19 7 19 81 133 -39 125 36 34 127 6 43 124 54 52 127 47 58
Uncertainty in time = +/- 27 secs
Prediction of 2009 Apr 4.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
[Top of Page][Return to Home Page]