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Three positive events were recorded by using visual and video techniques.
View the updated prediction.
Observers: 1 J Bradshaw,Samford Valley, Qld, AU 2 J Bradshaw,Samford Valley, Qld, AU 3 P Anderson,THE GAP,Brisbane,QLD,AU 4 P Anderson,THE GAP,Brisbane,QLD,AU 5 T Napier-Munn,Bellbowrie, Qld, AU 6(P) Prediction
Discussion:
The circle above is plotted at the expected 64 km diameter of Penthesilea. With 3 chords it is reasonable to say that the central line of the event was close to Peter's visual observation. Both Peter and Jonathan reported a slow Reappearance.
The figure below shows the light Curve of Jonathan's observation which shows both D and R being slow and with the points chosen to represent the times. If this is caused by a double star then the separation is only 1.3 milli arc seconds and the PA 220 degrees. The star magnitude is given as m 11.8 and the asteroid (bottom of curve) m 13.9 then the secondary would be about m 14.2.
It is also noted that this seems to be the first observed occultation for (271) Penthesilea, and there is no data in the usual places for rotational lightcurve results.
Observational Data:
Observation details for MP (271) Penthesilea By Star TYC 1397-00920-1 On 2009-01-29 at 12:56:00.0 _______________________________ Observer Jonathan Bradshaw Location Samford Valley, Qld, Australia Longitude +152:52:22.7 Latitude -27:21:22.8 Altitude 95 m Datum WGS84 Telescope Dobsonian Aperture 50 cm Seeing Steady Clear Timing GPS - time inserted Video with frame analysis Disappearance 12:56:10.22 Reappearance 12:56:14.78 Comments: Clear and steady using GSTAR-EX with 2x integration and Gamma 6. Subtracted 20ms from frame values. A late gradual dimming is seen in the light curve with a corresponding gradual brightening toward the end of the reapearence _______________________________ Observer Jonathan Bradshaw Location Samford Valley, Qld, Australia Longitude +152:52:22.7 Latitude -27:21:22.8 Altitude 95 m Datum WGS84 Telescope Dobsonian Aperture 50 cm Seeing Steady Clear Timing GPS - time inserted Video with frame analysis Disappearance 12:56:10.26 Reappearance 12:56:14.86 Comments: Clear and steady using GSTAR-EX with 2x integration and Gamma 6. Subtracted 20ms from frame values. A late gradual dimming is seen in the light curve with a corresponding gradual brightening toward the end of the reapearence _______________________________ Observer Peter Anderson Location THE GAP,Brisbane Longitude +152:55:57.9 Latitude -27:27:42.3 Altitude 170 m Datum WGS84 Telescope Newtonian Aperture 41 cm Seeing Steady Clear Timing Tape Recorder + time signal Visual, PE applied Disappearance 12:56:11.20 Reappearance 12:56:14.60 Comments: Was checking the field when the star disappeared (silly) When it re-appeared it was about 1/3 brightness for half a second then jumped to full brightness - stepped appearance. Time quoted is first re-appearance. _______________________________ Observer Tim Napier-Munn Location Bellbowrie, Qld, Australia Longitude +152:53:7.5 Latitude -27:33:29.5 Altitude 52 m Datum WGS84 Telescope SCT including Cass and Mak Aperture 36 cm Seeing Steady Clear Timing Stopwatch Only duration timed Disappearance 12:56:08.00 (absolute time adjusted) Reappearance 12:56:12.30 (absolute time adjusted) Comments: The event happened between 1056pm and 1057pm (12:56UT and 12:57UT) and the duration was 4.3 secs approx.