[meteorite-list] two fireballs

From: Jodie Reynolds <spacerocks_at_meteoritecentral.com>
Date: Mon, 25 Feb 2013 17:51:19 -0800
Message-ID: <174966831.20130225175119_at_spaceballoon.org>

[Note: frame references refer to my attached disassembly]

Hello Chris and all,

I agree: I don't see any impact event, certainly no shockwave is visible in
the bright frames.

I see the object of interest traveling away from the camera on a
steep angle and, between blooming and DCT errors, obscuring itself.
The digital iris tries its darndest to figure out what to do with
itself, and actually makes some pretty good decisions around frame 63
giving us some pretty nice images.

There certainly does appear, however, to be more than one parallel
path suggesting more than one component of the mass by frame 65/66. There's also some
pretty good sized component being shed earlier.

Chris, have a look at frames 64-80 in this disassembly to see if you
concur.

The following is my disassembly of that video with strictly the
relevant frames. No post-processing has been done, simply brought
the original MP4 container down, decompressed the 1920x1080p/20fps
transport into raw 8bit 4:2:0 YUV frames [the native frames], and
mapped them into lossless 24bit PNGs.

The video as I pulled it is an MPEG 4.2 container with AVC, High L4.0 Profile, VBR _at_
4.714-9.011Mbps, 20fps constant, progressive 4:2:0 YUV 16:9 encoding.

One reframe, GOP M=1,N=40.

The original timecode is branded: UTC 2013-02-14 04:06:50, but
there's no way of knowing how accurately the DVRs clock was
maintained.


105 frames contained, ~102MB here:

http://www.spaceballoon.org/chelyabinsk-meteor-frames-from-dash.zip

"Fair Use" is assumed, and all rights are retained by their original
holder.

Best Regards,

--- Jodie

Monday, February 25, 2013, 5:05:46 PM, you wrote:

> You are confusing optical aberrations for what is happening physically.
> Not only are there no components of the fireball colliding with other
> components, but no shock wave structures are apparent, either.

> Analyzing very bright point sources in video is difficult, as there are
> lens reflections, lens distortion, and various sensor artifacts. It's
> hard to actually locate the center of the meteor from such data.

> Chris

> *******************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com

> On 2/25/2013 5:56 PM, Steve Dunklee wrote:
>> http://www.youtube.com/watch?feature=endscreen&v=dBvotWfR3j4&NR=1
>> 26 seconds in on this video you clearly see two fireballs with the second one catching up to and impacting the first one.
>> The first one makes a shockwave and area behind it with less air pressure. the shock wave at over 10k mph is like a brick wall and acts like a funnel. Like following an 18 wheel semi truck too close to save gas. when the truck hits its brakes the suv behind it impacts. and kaboom. Meteors donT HAVE BRAKES AND CANT CHANGE VECTORS. So when the first piece is slowed down the following ones catch up.
>> Cheers
>> Steve Dunklee

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-- 
Best regards,
 Jodie                            mailto:spacerocks at spaceballoon.org

Received on Mon 25 Feb 2013 08:51:19 PM PST