|
|
A Positive observations were recorded by Chris Wyatt , using visual technique, and Dennis Lowe using video OSD technique.
View the updated prediction.
Observers:
1(M) J Broughton,Reedy Creek, QLD , AU CCD Drift
2(M) J Broughton,Brunswick Heads, QLD , AU Visual
3 D Lowe,Leyburn, QLD, AU Video OSD
4 C Wyatt,Tenterfield, NSW,AU Visual
5(P) Predicted, 24 Dec 2008
Discussion:
The ellipse above is plotted at the same area as expected 151 km diameter
of Berbericia using light curve data predicting the ellipse shape from
MPC.
With the two chords and the longer than maximum expected chord observed by
Dennis we can be fairly sure that he was close to the central line of the event.
This makes Chris' times look about 1.5 secs out… However… have a look at
a 3D model of Berbericia based on light curve data.
If you rotate the 3rd shape shown in 3D and overlay to the plot of the observed data
you get an approximation to what the the situation may have been below.
[Sorry about quality, but my software does make overlaying picutes easy-jt]
Observational Data:
Observation details for MP (776) Berbericia
By Star TYC 2419-00637-1
On 2009-01-06 at 14:47:50.0
_______________________________
Observer J Broughton
Location Reedy Creek,Reedy Creek, QLD 4227, Australia
Longitude +153:23:52.8
Latitude -28:06:30.3
Altitude 66 m
Datum WGS84
Telescope SCT
Aperture 25 cm
Seeing Slight flickering Clear
Timing Image analysis + time signal Drift scan
Missed
Comments: Use of an old CCD camera lacking a working mechanical shutter
Use of an old CCD camera lacking a working mechanical shutter
for this unnattended drift scan inspired a new method involving
comparison of image coordinates with an image taken when I returned.
As the event was a certain miss, that step wasn't implemented.
_______________________________
Observer J Broughton
Location Brunswick Heads,Reedy Creek, QLD 4227, Australia
Longitude +153:32:55.3
Latitude -28:33:6.1
Altitude 2 m
Datum WGS84
Telescope Dobsonian
Aperture 31 cm
Seeing Steady Clear
Timing Digital camera sound recorder Visual, no PE applied
Missed
Comments: Drift-through visual observation. A certain miss as the target
Drift-through visual observation. A certain miss as the target
was bright and any 1.3-magnitude drop would have been obvious.
_______________________________
Observer Dennis Lowe
Location Leyburn
Longitude +151:34:2.7
Latitude -27:58:58.3
Altitude 416 m
Datum WGS84
Telescope Refractor
Aperture 10 cm
Seeing Slight flickering Clear
Timing GPS - time inserted Video with frame analysis
Disappearance 14:47:55.12
Reappearance 14:48:07.92
Comments:
_______________________________
Observer Chris Wyatt
Location Tenterfield, NSW
Longitude +151:55:54.4
Latitude -28:57:15.4
Altitude 827 m
Datum WGS84
Telescope SCT including Cass and Mak
Aperture 20 cm
Seeing Steady Thin cloud < 2
Timing Tape Recorder + time signal Visual, PE applied
Disappearance 14:47:56.12
Reappearance 14:48:05.71
Comments: Thin cloud kept moving in and out of FOV whilst observing,
I sketched the star field of the star/asteroid and last noted a definite
split between them at 14h 28m UT before cloud intervened.
The cloud had broken in the region of the target star about 4 mins before
the occultation occurred, I had a comparison star in the FOV which I used
to determine if the target star had in fact been occulted or if it was
cloud interference, the occultation occurred without cloud interference.