[at-l] Question about WOW pic

[bullard@xxxxxxxxxxxx (Jim Bullard)]

Don't confuse the 'wobble' with the seasonal tilt. The tilt is the angle of
the Earth axis in relation to the Sun. Since it is not a 90 degree angle
relative to the Sun and it continues to lean the same way as it traverses
its orbit, the angle to the Sun changes. Polaris is many light years away
and the Earth doesn't go around it so our orientation to Polaris isn't
significantly affected by the Earth's tilt. The 'wobble' is another matter
but has a much smaller effect on our orientation to Polaris.

At 05:55 PM 3/8/2003 -0500, J Bryan Kramer wrote:
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>--
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>If I recall right without doing a web search, Ursa Minor ( the constellation
>which contains Polaris) is highest in the sky during northern hemisphere
>winter so I suspect you'd only be able to see Polaris on Kilimanjaro for a
>few days around the winter solstice, late in December.
>
>The earth does wobble 23 degrees which causes all sorts of interesting
>things like seasons. You can never see the moon or the sun directly over
>head unless you are within 23 degrees ( the tropics of Cancer and Capricorn)
>of the equator is another consequence. The 23 degree wobble is just one of
>the earth's many wobbles and twitches; another one causes the poles to
>wander around the sky.
>
>Bryan
>
>"Si vis pacem para bellum"
>
>   -----Original Message-----
>   From: Ken Powers [mailto:kdpo@pacbell.net]
>   Sent: Saturday, March 08, 2003 17:02
>   To: J Bryan Kramer; bogey1@cplx.net; at-l@mailman.backcountry.net
>   Subject: RE: [at-l] Question about WOW pic
>
>
>   Is that in the Winter or in the Summer? We just mentioned this puzzle to a
>trusted aviator/navigator. He mentioned that the earth tilts 23 degrees
>between winter and summer. So given the tilt that Polaris would be easy to
>see much of the year.
>
>   I still need to think about this more.
>
>    J Bryan Kramer <jbryankramer@msn.com> wrote:
>
>     The distance you can see to the horizon is calculated based on a simple
>     formula:
>
>     Distance formula: d * d = 12.75 * h
>     where d = distance to the horizon ( in kilometers)
>     and h = height above sea level ( in meters)
>
>     so 16,000 feet = about 4900 meters and the distance then would be:
>
>     d= sqrt(12.75 * 4900) = 249 km
>
>     one degree at the equator = 60 miles = 102 km so you gain 2.5 degrees by
>     being on top of the mountain
>
>     The reference I found gives the latidtude of Kilimanjaro as 3 deg south
>and
>     Polaris is actualy about a degree off the actual pole so you should just
>be
>     able to make out Polaris which would be right on the horizon. It would
>be
>     darn hard to see and you'd only be able to see it at the right time of
>the
>     year.
>
>     Bryan
>
>
>     "Si vis pacem para bellum"
>
>     > "Inhabitants of the Southern Hemisphere can't see Polaris, even
>     > if they just
>     > live one degree south of the Equator, and they don't have a pole star
>they
>     > can call their own. There's nothing even close to the South Pole. A
>couple
>     > of faint stars are about 10 degrees from the South Pole, but the
>nearest
>     > star of equivalent brightness to Polaris is nearly 15 degrees from the
>     > pole."
>     >
>     > Mt. Kilimanjaro, where the photo was taken, is in Tanzania, in
>     > the southern
>     > Hemisphere about 5 degrees south of the equator (130 miles south
>     > of Nairobi)
>     > and as the photographer's story goes, Polaris can be seen on the
>     > left of the
>     > photo. Could this be because of the 16,000 ft. altitude of
>     > Kilimanjaro gives
>     > a view above the curvature of the earth? Inquiring minds want to know.
>     > Whazup?
>     >
>     > SLIM aka Nancy
>     >
>     >
>     >
>     > _______________________________________________
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>     _______________________________________________
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>   Ken
>   http://home.pacbell.net/kdpo
>--
>
>_______________________________________________
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