Hi Jim:
You are of course referring to Meteors not Comets. The gaseous/particulate clouds streaming from comets are visible millions of miles out when they get energy from the sun.
Curt KU8L
Jim Danehy wrote:
the accepted opinion of astronomers is that you can see +6 magnitude stars without the assistance of a telescope or binoculars . . . . if AO 51 is +9 then it is virtually impossible to see it with the naked eye . . .
as for comets : well in order for comets to be seen those small particles that you see must be within the Karman line . . . which is at 62 miles (up) . . . the atmosphere pretty well ends at 75 to 80 miles up . . . in order for those objects to be seen they must be within the atmosphere where they "burn up" by friction against the "air" atmosphere (. . . AO 51 is some 300 miles or 400 miles up and the ISS is 200 miles up . . .
the sun is - 27 and we all know the brightest thing out there for us here on earth . . . . +6 for naked eye viewing . . . +9 is not visible
Jim W9VNE
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