Hi Chuck, You might be referring to a Gleanings for ATM's that appeared in the October 1989 S&T entitled "A jam-jar magnetometer as 'Aurora Detector'", pages 426-427. I checked the S&T web site but could not find a way to navigate to it from there (I'm looking at the hard copy I have in my library). If anyone interested in seeing the hard copy I could bring it to next week's SLAS board meeting. I did find this that might help: http://www.dcs.lancs.ac.uk/iono/aurorawatch/detectors FWIW, I just checked the NOAA website and saw they are showing that the very southern edge of the oval is currently sitting over northern Utah (though only barely). I don't plan any travels tonight but may spend some time on my roof "just in case". Provided it stops raining... patrick On 04 Aug 2010, at 14:32, Chuck Hards wrote:
Thanks, Joe, it's easy to make one, and I can't take credit for the idea. I think it came from Scientific American though I can't remember with certainty.
All you need is a good magnet, a small first-surface mirror, some fishing line, and a small, cheap laser pointer. I use a two-dollar red one from Walmart.
You also need to install it in a place with NO air currents at all. Mine was suspended at first in a glass milk bottle. Then I stuck it in the basement where it worked OK until I installed central air in the house this spring. Now I have to have the air conditioner off for an hour or two for it to settle down.
I'm going to make a plexiglass isolation chamber for it (read: "box"), so I can use it with the AC running.
Also if you can't find monofilament fine enough, use the thinnest, finest cotton or silk thread you can find.