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OCCULTATION OF UCAC2 16432689 BY 952 Caia
2008 July 07


A 5.3 second occultation was recorded by John Broughton, using CCD drift scan technique.

View the updated prediction.

Observers:
  1    J Broughton,Reedy Creek, QLD 4227, AU
  2(P) Prediction 2 July                    


Caia occultation - 2008 July 07

Discussion:

The circle above is plotted at the expected 81 km diameter of Caia. With only one chord it is not possible to determine whether John was north or south of the central line of the event. However the predicted and observed data suggest that the predicted path may have been very close to correct but the predicted time was about 13.5 seconds early.

The figures below show the drift-scan image of the occultation together and the data as analysed by John's Scanalyser software.

Caia occultation - 2008 July 07

Caia occultation - 2008 July 07

Observational Data:

Observation details for MP (952 ) Caia
By Star              UCAC2 16432689
On 2008-07-07  at 10:51:52.0
_______________________________

Observer   John Broughton
Location   Reedy Creek, QLD, AU
Longitude  +153:23:52.8
Latitude   -28:06:30.3
Altitude   66 m
Datum      WGS84
Telescope Newtonian
Aperture   51 cm
Seeing     Slight flickering Thin cloud < 2
Timing     Tape Recorder + time signal + shutter Drift scan
Disappearance  10:52:02.40
Reappearance   10:52:07.70

Comments: A positive drift-scan observation where preparation paid dividends.
A positive drift-scan observation where preparation paid dividends.
For peace of mind whenever a clear sky is not guaranteed, I prefer to align
the telescope on a previous night. As it was located in a crowded field,
I also imaged the target star, finding its magnitude to be 12.7 and opted to
limit the drift-scan exposure to 50s in avoidance of a left-end trail overlap.
The day of the event was raining at times and overcast 95% of the time.
Indeed it was overcast at 10:20 UT when I started cooling the CCD camera.
However by 10:40, low-level cloud had begun to break up and the observation
itself occurred inside the edge of clouds where they were not opaque. 
Luckily the transparency sufficed to allow a clearly positive result
to be recorded. As the trail is fainter in the last 15 seconds where the
event is located, I increased the uncertainty from the Scanalyzer result
and rounded the D and R times to the nearest tenth.
The duration comes out at 5.3s.  

Return to 2008 occultation results



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