Two occultation were recorded by John Broughton, using video OSD technique.

He also observed a clear miss for this event.

View the updated prediction.

Observers:
   1(M) J Broughton,Reedy Creek, QLD, AU     
  2    J Broughton,Brunswick Heads, NSW, AU 
  3    J Broughton,Pimlico, NSW, AU         
  4(P) Prediction, 18 March                 

        

122

123

Discussion:

The ellipse above is plotted at the best fit axis ratio as determined by Occult. With 2 chords and a miss we can be confident of the path of Thalia and that it was south of the predicted line. Two DAMIT 3D models has been overlaid on the measured ellipse and both show Reasonable fit. it is difficult to decide which is better so this observation will not be able to eliminate one of the models.

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

St2

this much noisier than Chord St3 below so the fitting has been given more weight to St3.

St3

Observational Data:

Observation details for MP ( 23 ) Thalia
By Star              TYC 2422-00001-1 
On 2015-04-28  at 08:35:52.0


_______________________________

Observer   John Broughton
Location   Brunswick Heads, NSW, AU
Longitude  +153:32
Latitude   -28:32
Altitude   5 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture    9 cm
Seeing     Slight flickering Clear 
Camera Type  LN-300-11673   PAL/CCIR      
Camera Delay -0.8
Timing     GPS - time inserted Video with frame analysis
Disappearance  08:35:50.91
Reappearance   08:35:52.51
Comments: Correction for converting DVR time stamp to UTC: -2.05s  

_______________________________

Observer   John Broughton
Location   Reedy Creek, QLD, AU
Longitude  +153:23
Latitude   -28:06
Altitude   66 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   25 cm
Seeing     Strong flickering Clear 
Camera Type  WAT120N+       PAL/CCIR      
Camera Delay -0.05
Timing     GPS - time inserted Video with frame analysis

Missed

Comments:   

_______________________________

Observer   John Broughton
Location   Pimlico, NSW, AU
Longitude  +153:29
Latitude   -28:54
Altitude   5 m
Datum      WGS84
Telescope Newtonian
Aperture   32 cm
Seeing     Strong flickering Clear 
Camera Type  WAT120N+       PAL/CCIR      
Camera Delay -0.07
Timing     GPS - other linking Video with frame analysis
Disappearance  08:35:49.36
Reappearance   08:35:52.96
Comments: Correction for converting DVR time stamp to UTC: -0.68s