Don't forget parallax. The geostationary satellites are not at an infinite
distance. The angles you measure to see them must be corrected for the
specific location. I once wrote a program for a TI 59 programmable
calculator to do this. It was published in their PPX program exchange. It
was that long ago. I never updated it because I never had a dish. I may be
able to find it buried in my old files but there are likely better programs
now available.
Also note the geostationary satellites are not. They do an analemma like
loop in latitude and slowly drift in longitude. No fix will be anything
close to a GDS that analyses up to 12 satellites of precisely known
location. But the principle is much the same.
Regards,
Roger Bailey
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From: "Brent" <[email protected]>
Sent: Thursday, December 09, 2010 4:51 PM
To: "Sundial List" <[email protected]>
Subject: Re: stop the earth
That's an interesting suggestion about the satellite dish.
I have a tv dish now, which is aimed at a geostationary satellite.
I think if I go measure its' inclination from the north/south horizon
and its' inclination from the east/west horizon I can determine my
location. It is easy to figure which satellite it is, so I can get an
accurate longitude for my location.
I think all geostationary satellites are positioned over the equator, so
latitude is an easy find.
Of course it's easy to buy a gps device, but where is the fun in that?
And how will we get around after the nuclear winter when all electronic
gadgets stop working?
Roger W. Sinnott wrote:
Brent,
Yes, I think you *could* determine your longitude by observing a
geosynchronous satellite whose location was known. There would be some
uncertainty if it wanders a little. Much more important, however, is
figuring out which geosynchronous satellite you are looking at. You'd
probably have to aim a dish at it and see what TV stations you get.
-- Roger
----- Original Message ----- From: "Brent" <[email protected]>
To: "Sundial List" <[email protected]>
Sent: Thursday, December 09, 2010 3:17 PM
Subject: stop the earth
I have been wondering why I can determine my latitude using simple tools
but not my longitude? The earth is a sphere, I would think if you can
determine one you can determine both.
The problem with calculating longitude seems to be the earth is rotating
on its' axis. If the earth stopped spinning, the sun would not rise and
set but stay put, and then I could determine the angle of the sun from
my horizon and thus determine my longitude.
Well that's not going to happen anytime soon. But if I could see a
geostationary satellite I could essentially do the same thing don't you
think?
I have seen orbiting satellites at dusk many times but does anyone know
if you can see geostationary satellites with the naked eye?
thanks;
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