Three chords were recorded , using Video OSD technique.

Seven other stations were registered for this event but were clouded out or had technical problems. Potentially another 3 chords may have been observed.

No clearly observed misses were recorded for this event.

View the updated prediction.

Observers:
  1    H Pavlov,St Clair, NSW, Australia
  2    T Barry,Werrington Downs
  3    D Gault,bservatory, N.S.W., Australia
  4(P) Prediction, JUly 4


        

Discussion:

The circle above is plotted at the expected 77 km diameter of Dysona. With three chords we can be confident of the path of Dysona and that it was north of the predicted line.

Two Damit 3D models has been overlaid on the plot and both show good fit. This means we cannot use this particular event to decide which of the two models is more accurate.

The ISAM model also shows one of the possible spin axes but again does not help in separating the two possible 3D inversion models. Many 3D models share this problem and occultations with multiple chords are one method of resolving the ambiguity.

The figure below shows the Tangra light curve of Dave Gault's occultation.

The figure below shows the Tangra light curve of Hristo Pavlov's occultation.

Observational Data:

Observation details for MP ( 1241 ) Dysona
By Star              UCAC2 27213579
On 2013-08-18  at 09:40:22.0

_______________________________

Observer   Hristo Pavlov
Location   St Clair, NSW, Australia
Longitude  +150:46
Latitude   -33:48
Altitude   68 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   35 cm
Seeing     Steady Clear
Camera Type  WAT910HX       AAV-PAL
Camera Delay -0.06
Timing     GPS - time inserted Video with frame analysis
Disappearance  09:40:24.61
Reappearance   09:40:29.90
Comments: http://www.hristopavlov.net/Observations/Positives/2013-08-18%20Dysona/Event.html
Report prepopulated by IOTA Reporting Add-in for OW ver.1.7

_______________________________

Observer   Tony Barry
Location   Werrington Downs
Longitude  +150:43
Latitude   -33:44
Altitude   31 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   25 cm
Seeing     Steady Clear
Camera Type  Grasshopper Express with ADVS              ADVS
Camera Delay 0
Timing     GPS - time inserted Video with frame analysis
Observation details for MP ( 1241 ) Dysona
By Star              UCAC2 27213579
On 2013-08-18  at 09:40:22.0

_______________________________

Observer   Dave Gault
Location   Kuriwa Observatory, N.S.W., Australia
Longitude  +150:38
Latitude   -33:39
Altitude   286 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   30 cm
Seeing     Steady Clear
Camera Type  Grasshopper Express with ADVS              ADVS
Camera Delay 0
Timing     GPS - time inserted Video with frame analysis
Disappearance  09:40:25.86
Reappearance   09:40:30.53
Comments:

Disappearance  09:40:25.07
Reappearance   09:40:30.01
Comments: S/N 2.17 @ 7.5fps  Report prepopulated by IOTA Reporting Add-in for OW ver.1.7