A 5.4 second occultation was recorded by Jonathan Bradshaw, using video OSD technique.

One clearly observed miss was recorded for this event.

View the updated prediction.

Observers:
  1    J Bradshaw,Samford Valley, Qld, AU
  3(M) J Broughton,Reedy Creek, QLD, AU
  4(P) Prediction



        

Discussion:

The circle above is plotted at the expected 32 km diameter of Sara. With one chord and a contraining miss We can be sure that Jonathan was south-west of the central line of the event.

The figure below shows the Limovie light curve of the occultation.

There is a hint of a step in the D and R which might signal a double star. I asked for a second opinion on this and Brian replies.

Thanks for sending on the observation of the occultation by Sara made by Jonathan Bradshaw.
I see the predicted duration was about 9 seconds, and Jonathan's event last about 6 seconds. So presumably some way off centre. The asteroid was moving quite slowly, at something like 0.002"/second, about 1-10th of the asteroid's diameter in a second.
To my mind the light curve looks more like one due to a slow occultation, maybe with diffraction effects rather than a double. The decay is reasonably steady. The increase does have a kink in the light curve, but looking at the noise when the star was visible, this could also be a noise effect.
I don't feel there is a need to assume a double star to account for the light changes, it would be very difficult to say where the double is indicated as there is no step. It may be telling us something about the edge of the asteroid being near to parallel to its direction of movement close to where the occultation occurred.

You may want to compare to the light curve I obtained at a grazing lunar occultation early this year, see the recent Southern Stars.
Regards,
Brian
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Based on this advice and my doubts, this event will be treated as a single chord. It will result in the same level of accuracy for the astrometry as if it was treated as double.

Observational Data:

Observation details for MP ( 533 ) Sara
By Star              UCAC2 26566386
On 2013-09-12  at 13:30:06.0

_______________________________

Observer   Jonathan Bradshaw
Location   Samford Valley, Qld, Australia
Longitude  +152:50
Latitude   -27:22
Altitude   80 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   36 cm
Seeing     Steady Clear
Camera Type  G-Star         PAL/CCIR
Camera Delay -0.07
Timing     GPS - time inserted Video with frame analysis
Disappearance  13:30:32.56
Reappearance   13:30:38.44
Comments: 6 frame gradual D and R in great confitions - possible double star
at 0 or 180 degrees PA?  Report prepopulated by IOTA Reporting Add-in for OW ver.1.7

_______________________________

Observer   Jonathan Bradshaw
Location   Samford Valley, Qld, Australia
Longitude  +152:50
Latitude   -27:22
Altitude   80 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   36 cm
Seeing     Steady Clear
Camera Type  G-Star         PAL/CCIR
Camera Delay -0.07
Timing     GPS - time inserted Video with frame analysis
Disappearance  13:30:32.80
Reappearance   13:30:38.24
Comments: 6 frame gradual D and R in great confitions - possible double star
at 0 or 180 degrees PA?
Report prepopulated by IOTA Reporting Add-in for OW ver.1.7