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OCCULTATION OF TYC-1397-00920-1 BY 271 Penthesilea
2009 January 29


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
    

Penthesilea occultation - 2009 January 29

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.

Penthesilea occultation - 2009 January 29

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.

    

Return to 2009 occultation results



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