|
|
Updated: 2009 MAY 04, 04:18 UT
Event Rank : 36
(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 Jun 15 UT, the 25 km diameter asteroid (1626) Sadeya will occult a 10.4 mag star in the constellation Pegasus for observers along a narrow path down the west coast of the North Island of New Zealand, passing Russell, Helensville, Hawera and Wellington.
In the case of an occultation, the combined light of the asteroid and the star will drop by 4.6 mag to 15.0 mag (the magnitude of the asteroid) for at most 1.6 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
175 25 41 -44 0 0 18 15 32 35 332 -16 175 36 4 175 15 17 176 14 28 174 37 12
175 12 33 -43 0 0 18 15 37 36 332 -16 175 22 46 175 2 21 176 0 28 174 24 56
175 0 28 -42 0 0 18 15 41 37 332 -16 175 10 30 174 50 26 175 47 33 174 13 40
174 49 21 -41 0 0 18 15 46 38 332 -16 174 59 14 174 39 30 175 35 39 174 3 20
174 39 11 -40 0 0 18 15 51 39 332 -16 174 48 53 174 29 29 175 24 44 173 53 53
174 29 52 -39 0 0 18 15 56 40 332 -16 174 39 26 174 20 19 175 14 44 173 45 16
174 21 24 -38 0 0 18 16 1 40 331 -15 174 30 50 174 11 59 175 5 36 173 37 27
174 13 43 -37 0 0 18 16 6 41 331 -15 174 23 1 174 4 27 174 57 18 173 30 23
174 6 48 -36 0 0 18 16 11 42 331 -15 174 15 58 173 57 38 174 49 46 173 24 2
174 0 35 -35 0 0 18 16 17 43 330 -15 174 9 38 173 51 33 174 43 0 173 18 23
173 55 4 -34 0 0 18 16 22 44 330 -14 174 4 0 173 46 9 174 36 58 173 13 23
173 50 13 -33 0 0 18 16 28 45 330 -14 173 59 2 173 41 24 174 31 36 173 9 2
173 45 59 -32 0 0 18 16 33 46 329 -14 173 54 43 173 37 16 174 26 54 173 5 16
Uncertainty in time = +/- 3 secs
Prediction of 2009 May 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]