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OCCULTATION OF TYC 6933-00036-1 BY 1 Ceres
2015 July 5

A 46.8 second occultation was recorded by Peter Graham, using video OSD technique. This event involved a very shallow dimming during the occultation that was faintly but distinctly recorded by Peter's video system. Diana Watson also monitored this event by visual means and did not observe an occultation although it is likely that the dimming was too small for her to detect. As such, it does not offer a confirming or constraining observation to that observed by Peter.

View the Personal prediction.

  1(M) D Watson,Thornton near Whakatane, NZ 
  2    P PBGraham,Martinborough, NZ         
  3(P) Prediction - 2015 Aug 22             


Ceres occultation__ 2015 July 5


The circle above is plotted at the expected 960 km diameter of Ceres. More accurate data on the size and shape of (1) Ceres is of course available from the current Dawn spacecraft mission. With only one chord it is not possible to determine whether Peter was north or south of the central line of the event although it is more likely that he was south of it as indicated by the prediction. Diana's observation does not constrain this conclusion.

The figures below shows the AOTA analysis of the light curve of Peter's observation.

Ceres Occultation_ 2015 July 5

Ceres occultation 2015 July 5

Observational Data:

Observation details for MP ( 1 ) ceres
By Star              TYC 6933-00036-1 
On 2015-07-05  at 08:18:42.0


Observer   Diana Watson
Location   Thornton near Whakatane, NZ
Longitude  +176:51
Latitude   -37:55
Altitude   3 m
Datum      Other
Telescope SCT including Cass and Mak
Aperture  200 cm
Seeing     Steady Clear other - list in comments
Camera Type  Visual         Other         
Camera Delay 
Timing     Tape Recorder + time signal Visual, no PE applied


Comments: Target star fairly low so was not able to see it till it had cleared the trees, hence did not see merging. This would not be a miss but drop in magnitude  too low to see visually. 


Observer   PBGraham
Location   Martinborough, NZ
Longitude  +175:29
Latitude   -41:14
Altitude   73 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   25 cm
Seeing     Slight flickering Thick cloud > 2 recording very faint.
Camera Type  Watec 910BD    PAL/CCIR      
Camera Delay 
Timing     GPS - time inserted Video with frame analysis
Disappearance  08:18:25.48
Reappearance   08:19:12.29
Comments:  A difficult recording lots of cloud after a clear beginning. I believe I had 2F integration set but the data seems to be not integrated.  


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