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An 8.5 second occultation was recorded by Diana Watson, using visual technique.
View the updated prediction.
Observers: 1(M) B Allen,Blenheim, NZ 2 D Watson,Thornton near Whakatane, NZ 3(P) Predicted 26 Sept
Discussion:
The circle above is plotted at the expected 87 km diameter of Cheruskia.
With only one chord it is not possible to determine whether Diana was north or south of the central line of the event.
However, assuming the updated prediction was approximately correct the longer
than expected chord of about 90 km would suggest that the chord might lie close to the central portion of the asteroid.
At first Bill seemed to have a signal buried in noise but after taking Diana's clear positive into consideration,
I have reached the conclusion that Bill was north of the path and only had noise in his lightcurve.
Past occultion observations have confirmed an oval shape with major axis about 84 km so it is not feasible for both
locations to have observed the event.
Observational Data:
Observation details for MP (568) Cheruskia By Star UCAC2 39243449 On 2008-10-01 at 11:42:00.0 _______________________________ Observer Bill Allen Location Blenheim, NZ Longitude +173:50:21.4 Latitude -41:29:30. Altitude 38 m Datum WGS84 Telescope SCT including Cass and Mak Aperture 40 cm Seeing Steady Clear Timing Tape Recorder + time signal Drift scan Missed Comments: Datum NZ1949 (topographical map) Very good observing conditions. SBIG STL 1001E camera used at f15 focus. _______________________________ Observer Diana Watson Location Thornton near Whakatane Longitude +176:51:48.4 Latitude -37:55:30.1 Altitude 3 m Datum Other Telescope SCT including Cass and Mak Aperture 200 cm Seeing Steady Clear Timing Tape Recorder + time signal Visual, no PE applied Disappearance 11:42:20.10 Reappearance 11:42:28.60 Comments: timed when shadow completely covered over the star and when star returned to full brightness.