Hi Joe, I'm speculating that because the entire fog mass is in motion, a time exposure would only show a uniform glow. To capture the filamentary structure, a fairly quick exposure would be needed. As I lay in bed last night waiting for sleep to ovetake me, I was awed by the memory of the fractal patterns of the fog filaments. They are exactly like the filamentary, fractal "bubbles and void" structure of the cosmos-at-large. I've just ordered an HD hard-drive camcorder, to replace the SD camcorder I bought last fall (that one will go to my daughter who wants to use it for theatrical work for school). I want to try taking video of the fog structures using my high-powered green lasers for illumination. The camcorder has the capability of sending a single HD frame to an external drive or printer. With luck I can then directly compare the fog structure to computer renderings of cosmic structure. Of course, dense fog is a requirement, so hopefully we'll get another episode once the camcorder arrives, before this winter is over. As an aside, I also want to use the HD camcorder to video things like Jupiter's moons & shadow events, lunar occultations, "artsy-fartsy" stuff. The hard-drive storage & frame-grabbing capability in HD makes it more attractive than the similar stuff I used to do with video-tape recorders. On Fri, Jan 23, 2009 at 11:24 PM, Joe Bauman <josephmbauman@yahoo.com>wrote:
That is interesting, Chuck. What would a long exposure look like while the lasers are tracing out the formation? -- Joe
--- On Fri, 1/23/09, Chuck Hards <chuck.hards@gmail.com> wrote: From: Chuck Hards <chuck.hards@gmail.com> Subject: [Utah-astronomy] Thick as pea soup To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Friday, January 23, 2009, 9:01 PM
If you live in a fog-enshrouded, low-lying area, it's a good night for laser fun. Even my low-power red pointer shows a visible beam in the fog.
You can see density differences in the fog by sweeping the beam of a green laser back-and-forth rapidly. Lower-density patches are darker, and there is structure to them. My daughter waved her laser horizontally, and I waved mine vertically with both fans intersecting in the middle. We got a good 3-D view of the fog density distribution in an enlarging cone with us at the apex. My daughter was surprised to see just how non-homogenous the fog layer really is. Much wispy, filamentary structure, very similar to astronomical nebulae.
It reminded me of those computer-generated maps of cosmic structure, also typically a cone-shaped region diverging away from our viewpoint. _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com
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