Perseids meteors plots - the 'red' portion is the actual meteor path length.
One Earthgrazer ( longest red path length) with will not satisfied the minimum
of 2 or more path length away from radiant while the rest did.
x2 Pi Erianus
x1 PiThe pc video system detected two long-trail meteors around 00:39 and at 01:43. I fished out the PDA and have a quick check on the planetarium sw. Perseids radiant was -3 degree( below horizon) and 1.5 degree then. They resembled grazing meteors- hitting the atmosphere at shallow angle and can be seen half way around the sky. [ remind me of the grazing red Taurids competing with the Leonids] The curvature trajectory is due to the wide angle lens distortion . Jupiter is the bright object at top of the frame.
Then at 02:32am i saw this text-book perfect Perseids real time in the monitor which prompted me to visit the nearby field to watch the sky. [Video of this bright Per posted to youtube is available here.] The 'indoor'-soccer court still felt lukewarm from the warm afternoon, with feet facing east I looked around the sky. A thin layer of clouds and the 'garing' moon. I could make out the 4- corner star of the Great Square of Pegasus, Jupiter and the triangle formed by Formahaut and Grus beta-alpha. In between was the mag2 beta Cetus. Closer to the horizon SE was Achernar. Perseus was blocked by the housing block. Nothing exciting happen through out the 1 hour there. X1 short bright yellowish meteor flashed near Jupiter. I scribbled the time on a piece of paper. [ this meteor was also detected by the video system]. Clouds drifting in and i went home.
Back at monitor screen a couple of meteors were already detected on my walk to the field. I watched the monitor for a while and walked to the window and gazed out. Around 5am a bright yellow short trailed meteor was seen and i checked the monitor nearby - yes it was there. I saw two other meteors - swift , yellowish with outer greenish tint. The b/w video can never deliver the pretty sight . Fatigue soon took over me and i went back to sleep leaving the automated sky sentinel to do its work.
A composite of meteors seen from 02:30 to 04:31. Jupiter dotted in the image above. Look carefully how the top two images grazing meteor appears to 'line-up' producing a long 'artificially' long meteor in the above image.
Composite plot from 04-5:55
By 6 am Pers radiant had shifted 06:01-06:28 am composite stack.
Aug 13 2009 local time. +8 UT
16 UT* /00:00-00:59 - x1 grazing meteor
17 UT /01:00 -01:59 - x1 grazing meteor
18 UT /02:00-02:59 - x2
19 UT /03:00-03:59 - x2
20 UT /04:00-04:59 - x9
21UT /05:00-05:59 - x9
22 UT/06:00-06:30 - x7 ( dawn 0630)
Total: 31 Meteors.
* UT date 16 hr Aug 12 '09