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OCCULTATION OF 2MASS 18312044-19262 (=UCAC3 142-319429) BY P9M1 Charon
2012 July 27


A 58.9 second occultation was recorded by William Hanna, using video OSD technique.
and a 17.9 second event was recorded by Steve Kerr, using Video OSD technique.

Five clearly observed misses were recorded for this event.

View the Special 2MASS prediction.

Observers:
  1    W Hanna,Alice Springs, NT,AU
  2    S Kerr,Rockhampton,QLD,AU
  3(M) J Bradshaw,Samford Valley, Qld, AU
  4(M) J Broughton,Reedy Creek, QLD, AU
  5(M) D Herald,Murrumbateman, NSW, AU
  6(M) J Talbot,Waikanae Beach, NZ
  7(M) B Loader,Darfield,NZ
  8(P) Prediction, 11 May

        

Charon occultation - 2012 July 27

Discussion:

The circle above is plotted at the expected 1186 km diameter of Charon. However, assuming the updated prediction was approximately correct the slightly longer than expected chord would suggest that the chord might lie close to the central portion of the asteroid. With 2 chords, and constraining misses, we can be confident of the path of Charon and that it was north of the predicted line.

The figure below shows William's Limovie light curve of the occultation and confirms the expected magnitude drop of 0.6 was seen.

Charon occultation - 2012 July 27

The figure below shows Steve's Limovie light curve of the occultation.

Charon occultation - 2012 July 27

The figure below shows Jonathan's Limovie light curve of the occultation.

Charon occultation - 2012 July 27
This shows an interesting 1 sample dip just before frame 2200 that is at a time that is consistent with the other two. However as his path is about 450 km south of the edge of the circle is seems unlikley to be a graze. Other possibilities are a small cloud, noise spike, piece of Earth orbit space junk, or could it be another Pluto moonlet or satellite of Charon, or ... !?

Observational Data:

Observation details for MP ( 9 ) Charon
By Star       2MASS 18312044-19262  =  UCAC3 142-319429
On 2012-07-27  at 14:38:07.0

_______________________________

Observer   B. Loader
Location   Darfield
Longitude  +172:06
Latitude   -43:28
Altitude   210 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   25 cm
Seeing     Strong flickering Clear
Camera Type  WAT120N        PAL/CCIR
Camera Delay 0.65
Timing     GPS - time inserted Video with frame analysis

Missed

Comments: spells of very poor seeing  Report prepopulated by IOTA Reporting Add-in for OW ver.1.6

_______________________________

Observer   William Hanna
Location   Alice Springs, Australia
Longitude  +133:53
Latitude   -23:42
Altitude   586 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   20 cm
Seeing     Slight flickering Clear
Camera Type  WAT120N+       PAL/CCIR
Camera Delay 1.31
Timing     GPS - time inserted Video with frame analysis
Disappearance  14:39:36.00
Reappearance   14:40:32.32
Comments: ~50% moon ~46 degrees below.  Light wind.

_______________________________

Observer   John Talbot
Location   Waikanae Beach, NZ
Longitude  +175:01
Latitude   -40:51
Altitude   5 m
Datum      WGS84
Telescope Newtonian
Aperture   25 cm
Seeing     Slight flickering Clear
Camera Type  WAT120N+       PAL/CCIR
Camera Delay 1.31
Timing     GPS - time inserted Video with frame analysis

Missed

Comments: Clear, calm, almost frost, No event  Using WATEC  borrowed form Terry Butt.

_______________________________

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 0.33
Timing     GPS - time inserted Video with frame analysis

Missed

Comments:   Report prepopulated by IOTA Reporting Add-in for OW ver.1.6

_______________________________

Observer   S. Kerr
Location   Rockhampton,QLD,AU
Longitude  +150:30
Latitude   -23:16
Altitude   50 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   30 cm
Seeing     Slight flickering Clear
Camera Type  WAT120N        PAL/CCIR
Camera Delay 0.65
Timing     GPS - time inserted Video with frame analysis

Missed

Comments:

_______________________________

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 Thin cloud < 2
Camera Type  G-Star         PAL/CCIR
Camera Delay 0.26
Timing     GPS - time inserted Video with frame analysis

Missed

Comments: Based on other observations, a miss, but the video did reveal a
tantalising ‘blip’ from 14:38:56.292 until 14:38:57.892 (1.6 seconds)
which may represent a 30km + object, but probably nothing more than
occultation shaped noise. If New Horizons crashes into an
unknown rock, I reserve the right to say ‘I told you so’ :)


______________________________

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 0.33
Timing     GPS - time inserted Video with frame analysis

Missed

Comments: DVR problems  caused  gap in observation.

        

Return to 2012 occultation results



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