[Laser] street light EME

[J Forster]

I tried this experiment in about 1971 or 2 using a Boller & Chivens 24"
telescope, PMT photometer, and a Tektronic 535A scope with Nelson Ross
spectrum analyzer plug-in. I was not looking at the moon, but at the
sky. There was significant 120 Hz and various harmonics. My point is
that make sure your signal is actually coming from the Moon, not your
sky. Yes, I get it with the 50-60 Hz bit.

Best,
-John



Tim Toast wrote:

> Hello all
> i just wanted to remind everyone with a telescope or other
> large optics with PGP RX's or other receivers mounted to
> it, to try pointing it at the dark side of the moon this
> weekend during the first quarter moon phase. Just for fun
> of course. Dont expect to hear much, but if you have some
> of the DSP software, try listening for the 50hz (100hz) or
> 60hz (120hz) buzz from countries on the alternate power
> frequencies.
> If you have narrow band filters for the sodium street light
> wavelengths (in the 550nm to 625nm range) that would
> definitely help. But even if you dont i'd still try it
> anyway, if for nothing else, practice for this winter and
> next year :) A million street lights cant be wrong...
>
> During the first quarter phase, the moon will drift away
> from where you're pointing if the telescope isn't driven,
> but it drifts off the dark side into space, so you don't
> have to worry as much about getting the lit portion of the
> moon in the field - where as in the last quarter phase,
> things will be reversed and the lit portion of the moon
> will drift INTO your field of view with non-driven scopes.
> I guess you will be limited by the size of your photo
> detectors as to how much of the dark side (earth shine
> side) will fill the detectors FOV. With equatorial driven
> scopes you can get the maximum amount of earth-shine area
> and not worry too much about blinding the detector. But
> with un-driven scopes, you might be better off with lower
> magnifications so you wont have to move the scope too often
> while tracking it. If you can track the moon for an hour or
> more, use the highest res settings on your DSP software
> (say 120 second/dots with Argo for instance) listening as
> hard as you possibly can near either 100 Hz or 120 hz
> depending on which country you are in.
> Also go get yourself a copy of 'Home Planet' software, it's
> free and shows a view of the earth from the moon in real
> time so you can see which parts of the earth are visible
> from the moon at any point in time. -you can also go
> backward or forward to any date and time (see the next
> lunar eclipses in late August of this year and february
> next year).
> I went back to see how things looked at the time Yves F1AVY
> was seeing 120 hz buzz from his location in France during
> an eclipse. It looks like most of the buzz was coming from
> south America, although the moon was rising on the east
> coast of the USA too and so that also contributed to the
> total signal i'm sure - New York and Manhattan are probably
> among the brightest 120hz sources on earth. In addition,
> Saudi Arabia is also on 60hz power, so it may have also
> contributed some. The moon rose fully eclipsed from my
> location in Alabama that night, i remember it well.
> So anyway, it's worth a try if you're set up for it. Here
> is a link to Yves' pdf file on his experiment if it is
> still posted there:
> http://partner.oodr
> ve.com/easyshare/wjshacc?action=view&key=vDpeJh33NYFU&isi=
> 109692&ci=50044&wid=29
>
> or try this one:
> http://tinyurl.com/24729z
>
> several people have the file so if all else fails ask one
> of us for it via direct email.
>
> links to Yves posts on this topic:
> http://mailman.qth.net/pipermail/laser/2007-June/001856.html
> and
> http://mailman.qth.net/pipermail/laser/2007-June/001858.html