At 13:10 15/06/02, Tom Wagner wrote: >Greetings, > > >Now, I have a Navy signal mirror that a person can accurately aim. You can >tell where the light is being directed by aiming a fuzzy spot of light that >is seen in a hole in the center of the mirror. This is probably a rhetorical >question but, is it conceivable that an astronaut could signal someone on >the earth below with a 4 x 6 inch mirror held up to a window in the ISS? >Would be nice huh. Probably never happen though. That would be a great >school project! Tom, If you calculate it properly, a square inch of a specular reflector at 1000 miles is magnitude 2.0 . So your 24 sq. inch mirror would give a maximum brightness at 1000 miles of magnitude -1.5, and at a range of 500 miles , 4 times brighter at -3.0. allowing for all the projections involved lets allow a magnitude less , so its -2, just a bit fainter than jupiter. Unlike its use by the Navy, the system would only work for unassisted vision under the usual visual satellite observing geometry, unless you made the mirror a bit bigger say 31 by 31 inches to get mag -6 flashes, which could be observed in daylight. Of course if a school had an lx200 mounted telescope and the satellite tracking software to drive it, daylight working would seem a strong possibility Tony Beresford ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org http://www2.satellite.eu.org/sat/seesat/seesatindex.html
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