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Updated: 2005 SEP 26, 15:52 UT
Event Rank : 99
(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 2005 Oct 07 UT, the 142 km diameter asteroid (895) Helio will occult a 11.7 mag star in the constellation Pegasus for observers along a path passing over the far north-western corner of Western Australia.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.1 mag to 13.6 mag (the magnitude of the asteroid) for at most 13.8 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Ron Stone, 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
110 58 50 -34 0 0 11 43 22 31 22 -13 110 8 54 111 48 38 109 38 52 112 18 26
111 28 5 -33 0 0 11 43 16 32 21 -14 110 38 47 112 17 14 110 9 9 112 46 39
111 56 41 -32 0 0 11 43 10 33 21 -14 111 8 1 112 45 14 110 38 45 113 14 18
112 24 42 -31 0 0 11 43 4 35 21 -15 111 36 37 113 12 40 111 7 42 113 41 24
112 52 10 -30 0 0 11 42 57 36 21 -16 112 4 38 113 39 35 111 36 3 114 8 0
113 19 7 -29 0 0 11 42 50 37 20 -16 112 32 6 114 6 1 112 3 50 114 34 7
113 45 34 -28 0 0 11 42 43 38 20 -17 112 59 3 114 32 0 112 31 5 114 59 48
114 11 35 -27 0 0 11 42 36 39 20 -18 113 25 32 114 57 32 112 57 51 115 25 5
114 37 10 -26 0 0 11 42 29 40 20 -18 113 51 33 115 22 41 113 24 8 115 49 58
115 2 21 -25 0 0 11 42 22 41 20 -19 114 17 10 115 47 28 113 50 0 116 14 30
115 27 10 -24 0 0 11 42 14 42 20 -19 114 42 22 116 11 54 114 15 27 116 38 42
115 51 39 -23 0 0 11 42 6 43 19 -20 115 7 13 116 36 0 114 40 31 117 2 35
116 15 48 -22 0 0 11 41 58 44 19 -21 115 31 43 116 59 48 115 5 14 117 26 11
116 39 39 -21 0 0 11 41 51 45 19 -21 115 55 54 117 23 20 115 29 37 117 49 31
117 3 13 -20 0 0 11 41 42 46 19 -22 116 19 47 117 46 35 115 53 41 118 12 36
117 26 31 -19 0 0 11 41 34 47 19 -22 116 43 23 118 9 37 116 17 28 118 35 27
117 49 35 -18 0 0 11 41 26 48 19 -23 117 6 43 118 32 25 116 40 58 118 58 5
118 12 26 -17 0 0 11 41 17 49 19 -23 117 29 49 118 55 0 117 4 13 119 20 32
118 35 4 -16 0 0 11 41 9 50 19 -24 117 52 41 119 17 24 117 27 14 119 42 47
118 57 31 -15 0 0 11 41 0 51 19 -25 118 15 21 119 39 38 117 50 3 120 4 53
119 19 47 -14 0 0 11 40 51 52 18 -25 118 37 50 120 1 42 118 12 39 120 26 50
119 41 54 -13 0 0 11 40 42 54 18 -26 119 0 8 120 23 38 118 35 3 120 48 39
120 3 52 -12 0 0 11 40 33 55 18 -26 119 22 16 120 45 25 118 57 18 121 10 21
120 25 42 -11 0 0 11 40 23 56 18 -27 119 44 16 121 7 6 119 19 24 121 31 56
120 47 25 -10 0 0 11 40 14 57 18 -27 120 6 7 121 28 41 119 41 20 121 53 26
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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