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Steve - WB3HUZ
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« on: November 02, 2008, 08:43:30 PM »

Some shots I received by email from Yellowknife Canada.


* au1.jpg (21.28 KB, 600x400 - viewed 691 times.)

* au2.jpg (25.23 KB, 600x400 - viewed 696 times.)

* au3.jpg (16.44 KB, 400x600 - viewed 660 times.)
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Bill, KD0HG
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304-TH - Workin' it


« Reply #1 on: November 02, 2008, 08:58:58 PM »

Thanks, Steve.
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Steve - WB3HUZ
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« Reply #2 on: November 02, 2008, 09:06:47 PM »

I'd love to see something like this once. Too far south here.
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AF9J
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« Reply #3 on: November 02, 2008, 10:15:07 PM »

That's too bad Steve,

I'm far enough north, that I've seen more than few auroras.  They're eerily beautiful.  In some ways - it's awe inspiring to me, watching what looks like blue green flames dancing in the sky.   
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ve6pg
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« Reply #4 on: November 02, 2008, 10:35:35 PM »

...how old are these pics?...no snow yet in yellowknife,..too early fer that....sk...
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...Yes, my name is Tim Smith...sk..
Ed-VA3ES
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« Reply #5 on: November 02, 2008, 10:39:51 PM »

Up here, we see a few auroras from time-to-time.  Unfortunately, the city lights mask them most of the time, and one needs to go out into the rural areas to view them. 
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John K5PRO
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« Reply #6 on: November 02, 2008, 10:53:54 PM »

About 6-7 years ago, we saw Aurora Boreallis here in New Mexico!
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K9ACT
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« Reply #7 on: November 02, 2008, 11:40:48 PM »

Some shots I received by email from Yellowknife Canada.

Lovely but it would be nice to know when the pics were taken..... presumably, not recently?

As a point of interest, for those who think they are too far South to see Aurora, I thought so too until we moved out to the country and away from city lights.

We have seen Aurora here that didn't even require looking North.  We could face South and still see it and we are only 42 degs North.

For 10 years I spent every clear, dark night outside with my telescopes and rarely missed a show.  Many a night I was all set up to start imaging only to find the object fade away on the computer.  Walk outside and my dark sky was on fire and I would just watch the show. 

Other times I would go out to collect the film or images only to find that is was completely over exposed which usually meant I had missed a show during a long exposure.

js





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KL7OF
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« Reply #8 on: November 03, 2008, 08:32:32 AM »

The Aurora can be heard as well as seen....Many times in Dec-Jan while working in the Prudhoe Bay oil fields...The noise can be quite loud at times...
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WA1GFZ
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« Reply #9 on: November 03, 2008, 08:55:07 AM »

I saw a show like that once  in summer of '70. My egg plant buddy and I were in front of our high school one night and noticed green in the sky. It lasted about 15 minutes.
One other time we had a lot of red in mid '80s. I was on 75M and the band shut down during the show.
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Carl WA1KPD
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« Reply #10 on: November 03, 2008, 03:34:31 PM »

Frank

I saw that one too.  A group of us were at a.... deserted gathering spot in Essex on the Connecticut River. I think we were discussing philosophy, whirled peas or something.

Didn't realize was I was seeing was induced by nature until someone else observed it too.

Only one I've ever seen

Carl

/KPD
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Carl

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Mike/W8BAC
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« Reply #11 on: November 03, 2008, 05:53:20 PM »

Quote
The Aurora can be heard as well as seen....Many times in Dec-Jan while working in the Prudhoe Bay oil fields...The noise can be quite loud at times...

Steve,

I have worked on the north slope many times myself. I'm not sure what you mean here  by "the noise can be quite loud at times". Do you mean audible noise or radio noise? If audible, what dose it sound like?

The best show I ever saw was in Yellow Knife 1989.

Mike
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KL7OF
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« Reply #12 on: November 04, 2008, 09:03:13 AM »

The aurora makes an audible noise....It was loud enough to be heard over the steady background drone of the distant diesel powered generators..... Hard to describe the sound, but sort of like dropping a bucket full of small stones into a big deep tank that is half full of water...
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K9ACT
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« Reply #13 on: November 04, 2008, 12:15:09 PM »

The aurora makes an audible noise....It was loud enough to be heard over the steady background drone of the distant diesel powered generators..... Hard to describe the sound, but sort of like dropping a bucket full of small stones into a big deep tank that is half full of water...

I have heard this before but it is hard to reconcile with the fact that the Aurora takes place in a vacuum.

By what mechanism would the sound waves reach our ears?

I just skimmed the entire Wiki article and found no reference to sound, even in the "folklore" section.

js
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WB2EMS
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« Reply #14 on: November 04, 2008, 02:10:14 PM »

Quote
I have heard this before but it is hard to reconcile with the fact that the Aurora takes place in a vacuum.

By what mechanism would the sound waves reach our ears?

Same question here, but it seems I've read of a mechanism for direct electrical stimulation of the inner ear that may be in play here, and is apparently in play sometimes for meteors. In about 1968, a large meteor crossed the US from east to west and landed out someplace in western Canada if I recall correctly. I distinctly remember *hearing* a sputtering and crackling noise that made me look up and see it flashing as a green fireball across the sky with bits and pieces 'popping' and coming off it along the way. It must have been at a good altitude if it managed to stay intact for 3000 miles, and the 'sound' was arriving pretty directly from it - not long behind the visual image as I was used to with high altitude jet aircraft.

I had never thought of that until I read about that direct electrical stimulation. I think the thread may have even been on here.

Don't know if that's the mechanism, but that would be my first guess. I've seen aurora from the southern shore of lake ontario fairly frequently in the 70's and early 80's, and in the 80's have seen it overhead and even south of here in central NY, and on those occasions it was not only the ghostly green and white, but also red. Never heard it.

Listening to Slopbucket on 6 meters during a January VHF sweepstakes years ago we heard some stations coming in via aurora. What that does to a human voice makes the hair stand up on the back of your neck! Shocked

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73 de Kevin, WB2EMS
Steve - WB3HUZ
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« Reply #15 on: November 04, 2008, 02:50:29 PM »

The aurora does not take place in a vacuum. There would be no aurora if a vacuum existed. The light you see is caused by the collision of charged particles (mostly electrons) from the sun with atoms in the upper atmosphere. Collison with oxygen produces red and green colors and nitrogen blue.
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K9ACT
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« Reply #16 on: November 04, 2008, 06:58:37 PM »

The aurora does not take place in a vacuum. There would be no aurora if a vacuum existed. The light you see is caused by the collision of charged particles (mostly electrons) from the sun with atoms in the upper atmosphere. Collison with oxygen produces red and green colors and nitrogen blue.

As someone we all know and love once said, "that depends on your definition of" vacuum. 

The base of the Aurora is about 50 miles up.  By most definitions, that is a vacuum enough to prevent sound from traveling.

js
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AF9J
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« Reply #17 on: November 04, 2008, 07:03:50 PM »

Listening to Slopbucket on 6 meters during a January VHF sweepstakes years ago we heard some stations coming in via aurora. What that does to a human voice makes the hair stand up on the back of your neck! Shocked



Yes it's kind of eerie.  The last Aurora I worked, was in Dec. 2006 on 2m.  I mainly did CW, but I heard a guy up in the Duluth. MN area doing SSB.  It almost sounded like a bestial growl, when he was calling CQ.  At other times when I've worked Au, the voices have sounded kind of watery.

73,
Ellen - AF9J
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WB2EMS
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« Reply #18 on: November 04, 2008, 07:46:48 PM »

Quote
I heard a guy up in the Duluth. MN area doing SSB.  It almost sounded like a bestial growl, when he was calling CQ.  At other times when I've worked Au, the voices have sounded kind of watery.

On the lower bands it's mostly the watery stuff I notice. But up on 6 and 2 meters the doppler shift is larger and the distortion gets more severe. Not an issue on CW with the little "hiss hiss hiss", but the first time I heard it on SSB voice I was doing a January VHF sweepstakes effort in a tiny 10x10 cabin on a hill south of Rochester NY at about 1 am on a cold, dark, lonely, winters night. There were 3 of us up there and it creeped us right out. It's the whole human but "no human should make noises like that" thing.

The only thing I can compare it to is a scene from one of the early Star Trek movies. They were finishing commissioning the new Enterprise and some folks beamed aboard and the transporter was screwed up and reassembled them improperly. They made some very similar sounding noises as I recall.


Back to the hearing aurora stuff. I did some searching on hearing meteors and came up with these sites. Apparently folks *are* hearing at least meteors - which agrees with my childhood experience. Electrophonic’ meteors they call them.  Grin

http://science.nasa.gov/headlines/y2001/ast26nov_1.htm
http://en.wikipedia.org/wiki/Microwave_auditory_effect
http://www.earthsky.org/radioshows/52754/whoosh-can-you-hear-a-meteor-streak-past


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73 de Kevin, WB2EMS
K9ACT
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« Reply #19 on: November 04, 2008, 11:52:06 PM »

Quote
I heard a guy up in the Duluth. MN area doing SSB.  It almost sounded like a bestial growl, when he was calling CQ.  At other times when I've worked Au, the voices have sounded kind of watery.

Back to the hearing aurora stuff. I did some searching on hearing meteors and came up with these sites. Apparently folks *are* hearing at least meteors - which agrees with my childhood experience. Electrophonic’ meteors they call them.  Grin


One of your links claims that a meteor 100 km up would boom 5 minutes later.  He probably did the math correctly but I would still like to know how the sound waves could travel in such thin air.  Note I did not say vacuum this time.

More importantly though, keep in mind that many meteors reach the ground and we even have a name for them, meteorites.  So between the time they start heating up when hitting the atmosphere and the time they hit the ground, it is obviously possible to hear one if we are in the right place at the right time and allowing for the sound travel time.  If it crashes through you bedroom ceiling, no allowance is necessary.

I have never heard of the Aurora ever hitting the ground.

js
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WB2EMS
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« Reply #20 on: November 05, 2008, 09:21:21 AM »

The one that I 'heard' went transcontinental and landed out northwest if I recall correctly, so my assumption is that it must have been quite high. It looked and sounded like it was only a mile or so away. It was big, with an apparent size near that of the moon - clearly a big chunk of something. I could hear and see pieces exploding off of it with crackling and popping sounds like a big wood fire. The sound and visual were arriving simultaneously, I could 'hear' the pops as pieces separated from the main meteorite.

It's funny that until reading that thread, wherever it was, about electrophonic meteors years ago, I had never thought about the immediacy of the audio. I was an experienced airplane watcher and was used to seeing a high altitude jet in one part of the sky and hearing it's engine roar coming from another part of the sky far behind, but that thought never occurred to me with the meteor.

I have no idea what's going on with 'hearing' aurora, but I am curious as to what those folks had experienced and would like to hear more about it.
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73 de Kevin, WB2EMS
Steve - WB3HUZ
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« Reply #21 on: November 06, 2008, 09:46:27 PM »

http://www.acoustics.hut.fi/projects/aurora/BNAM-ukl.pdf

and

http://members.tripod.com/~auroralsounds/aslist.html

and  (this one is quite extensive)

http://lib.tkk.fi/Dipl/2005/urn007898.pdf


and also


Observations of Acoustic Aurora in the 1–16 Hz Range
R. W. Procunier
Lockheed Palo Alto Research Laboratory 3251 Hanover Street, Palo Alto, California 94304.

ABSTRACT

Summary Acoustic aurora have been heard by long-term residents of the artic. They have also been recorded on microbarographs. Acoustic events associated with aurora are now reported in the near infrasonic range (1–16 Hz) at Barrow, Alaska. These observations were made with the aid of a resonant detector achieving a high signal-to-noise ratio similar to that used in extending the rocket-grenade technique to 109km. Over 100 impulsive events of a quasi-repetitive nature were recorded on a patrol basis during January 1970. Acoustic events were correlated with disturbed magnetic conditions and optical aurora but uncorrelated with lower-frequency auroral microbarograph events at College or Inuvik.

It is hoped that these initial observations will persuade interested parties to a more complete study of this phenomena and encourage an explanation of the generation mechanism for auroral infrasonic waves.

(Received 1971 July 1)
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