|
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.