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A 10.2 second occultation was recorded by Dave Herald, using video OSD technique.
View the updated prediction.
Observers: 1 D Herald,Murrumbateman, NSW, AU 2(P) Prediction, 4 July
Discussion:
We have the unusual situation of having a second event for the same object
in the same UTC day. In fact just 3 hours appart.
The first event had 6 chords and a constrainig miss.
It seems reasonable that for this second event that the shape and orientation
of the shadow will be similar and that the offset of the prediction line should be similar.
The ellipse above is plotted at same axis ratio and size as the first event but
has been rotated to give a good fit to the observed points.
With only one chord it is not possible to determine whether Dave 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 96 km would suggest that the chord might lie
close to the central portion of the asteroid.
The central chord position is abou 81 km North of the predcted line.
Sadly there is no Damit/ISAM/Miriade 3D model to help refine the analysis.
The figure below shows the Occular plot of Tangra analysis of the occultation.
Observational Data:
Observation details for MP ( 576 ) Emanuela By Star UCAC2 22105646 On 2013-07-26 at 11:50:16.0 _______________________________ Observer Dave Herald Location Murrumbateman, NSW, AU Longitude +148:59 Latitude -34:57 Altitude 594 m Datum WGS84 Telescope SCT including Cass and Mak Aperture 40 cm Seeing Steady Clear Camera Type WAT120N+ PAL/CCIR Camera Delay 0.05 Timing GPS - time inserted Video with frame analysis Disappearance 11:50:09.42 Reappearance 11:50:19.62 Comments: Report prepopulated by IOTA Reporting Add-in for OW ver.1.7