Thinkgeek sells this laser pointer with a beam divergence of 1.2 milli-radians.
Ok, fine, this page lists a few others, and it looks like the best they can come up with is a 0.5 mrad. Geosynchronous orbit is 35786 kilometers up. Using the power of tan(x) ~ x for small x (and noting that 5e-4 radians is fucking small), this gives a beam diameter (assuming a point source at the laser) of 17.893 kilometers. This seems to work out to the irradiance at that satellite is something like a factor of 3.1234e-15 smaller than it is at the source. In conclusion,
Thank you, Lois. |
No comments:
Post a Comment