[amsat-bb] Re: some additional comments on visual sighting
jdanehy at cinci.rr.com
Thu Nov 6 14:25:27 PST 2008
Yup ya got me but you knew what I meant to say . . . I guess we have become
used to that over the political season, listening to so much mis-statement .
. . mea culpa OM . . . being informed beats the alternative . . . ya
need astmosphere to see those little particles of sand from meteors . . .
comets are way out there in space where there is no atmosphere . . . they
are large too
TNX 73 Jim W9VNE
----- Original Message -----
From: "Curt Nixon" <cptcurt at flash.net>
To: "Jim Danehy" <jdanehy at cinci.rr.com>
Cc: <amsat-bb at amsat.org>
Sent: Thursday, November 06, 2008 2:57 PM
Subject: Re: [amsat-bb] some additional comments on visual sighting
> 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.
> 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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