From: pauld@exploratorium.edu
Date: Mon Apr 22 2002 - 19:37:01 PDT
Message-Id: <200204230236.g3N2avx02681@isaac.exploratorium.edu> From: pauld@exploratorium.edu Subject: Re: pinhole Re: The cost to make a laser Date: Mon, 22 Apr 2002 19:36:57 US/Pacific
Hi Algis
Green light is in a wavelength range that the human eye is more sensitive to than
red light. So for the same power it appears brighter.
Also air scatters green light more than red light. (proportional to the fourth
power of the frequency.)
Paul D
> Can anyone try to explain the physics of the skypointer? How should it be able to have
a
more visilbe beam than any other laser?
>
> Algis Sodonis
>
> pinhole@exploratorium.edu writes:
> >What ho, Art!
> >
> >Just in case you're in the market for a relatively inexpensive green
> >laser, and a hand-held model will do, read on...
> >
> >Howie Glatter of New Jersey sells his 532-nm "SkyPointer" for about
> >$240 <http://www.skypointer.net/>. I bought one last fall, and am
> >thoroughly satisfied with it. The SkyPointer makes a very cool laser
> >pointer. It also allows a physics teacher to show how the
> >double-slit interference pattern differs for shorter wavelength
> >waves. Best of all, the SkyPointer's beam is visible to dark-adapted
> >eyes as it travels through ordinary air -- no chalk dust necessary!
> >Thus, the SkyPointer earns its name by being a fantastic tool for
> >pointing out objects in the night sky. When pointed skyward, its
> >beautiful green beam seems to extend dozens of meters into the air --
> >far enough to pinpoint individual stars to those in your immediate
> >vicinity without much of a parallax problem. Any astronomy teacher
> >should love it.
> >
> >By the way, I own no SkyPointer stock and get no kick-backs. ;-)
> >
> >- Tucker
> >
> >Art Fortgang wrote:
> >>Metrologic sells lasers in the 600 nm range (red-
> >>orange) for about $300. Their green laser (about 550
> >>nm) costs nearly $800. I think I understand why the
> >>green laser ought to cost more to manufacture, but I
> >>don't know why it should be nearly three times as
> >>expensive (assuming the cost to consumer ratio roughly
> >>equals the manufacturing cost ratio of the two). Does
> >>anyone know why there is a 2.5:1 ratio in
> >>manufacturing costs.
> >
> >--
> >***********************************
> >Tucker Hiatt, Director
> >Wonderfest
> >P.O. Box 887
> >(39 Fernhill Avenue)
> >Ross, CA 94957
> >hiattu00@usfca.edu
> >415-577-1126 (voice)
> >415-454-2535 (fax)
> >http://www.wonderfest.org
> >
> >Truth is a great flirt. - Franz Liszt
> >***********************************
> >
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