Re: Paint the Moon

[Sandin <sandint@NCAT.EDU>]

Another thought: To put most of the beam on the reflector, we can use
                sin theta = 1.22 lambda/D
        with sin theta = theta (in rad) = about 1/(800 million)
                and lambda = about 400 nm
to show the diameter of the aperture of the laser pointer would have to be
about 400 meters! I think I'll use this for a problem in Physics II in a
few weeks.

On Thu, 25 Oct 2001, Sandin wrote:

> The moon is about 400 million meters away. The reflector array has a
> size of the order of 1 meter. Even if the beam could be kept from
> spreading, the person holding the pointer would have to keep it aimed to
> within about 1/(400 million) radian or about 1/(10 million) degree. I'm a
> bit shakier than that.                          Tom Sandin