On Mon, 20 Aug 2007 09:40:34 -0400, Wayne.B
wrote:

On Mon, 20 Aug 2007 22:02:33 +1000, Herodotus
wrote:

I have looked at these links and have spent the last few hours
wandering about the web. What I cannot find out is whether I can
receive these photos south of the equator. Seems like a great system
at a reasonable cost. Can you advise please.

That's really a two part question. I'm reasonably certain that you
could receive the pictures but I don't know if the satellites are set
up to capture southern hemisphere images.

Is it worth noting that CRTs need to be aligned properly, according to
the local version of the earths magnetic field?It is different
according to the latitude, especially which hemisphere you are in.
Flat screens don't care.

Casady

* Richard Casady wrote, On 8/20/2007 10:57 AM:
On Mon, 20 Aug 2007 09:40:34 -0400, Wayne.B
wrote:

On Mon, 20 Aug 2007 22:02:33 +1000, Herodotus
wrote:

I have looked at these links and have spent the last few hours
wandering about the web. What I cannot find out is whether I can
receive these photos south of the equator. Seems like a great system
at a reasonable cost. Can you advise please.
That's really a two part question. I'm reasonably certain that you
could receive the pictures but I don't know if the satellites are set
up to capture southern hemisphere images.

Is it worth noting that CRTs need to be aligned properly, according to
the local version of the earths magnetic field?It is different
according to the latitude, especially which hemisphere you are in.
Flat screens don't care.

You just turn the tube up-side-down for the Southern hemisphere.

Really.

When I worked on an orbiting telescope we discovered that the star
trackers had insufficient magnetic shielding. I had to create an
ephemeris database for the magnetic field in orbit, and apply the
corrections to the nav solution.

I doubt there are many using CRTs for computers on boats. A bigger
issue is compass corrections.

On Mon, 20 Aug 2007 11:54:37 -0400, Jeff wrote:

I doubt there are many using CRTs for computers on boats. A bigger
issue is compass corrections. You want the radar close to the
compass so you can see both easily, unfortunately. The compass is an issue.

Perhaps not for computers, but there are both radar and sonar in use,
many with a CRT all you could get,and on some very small boats. Many
prefered CRT for the good visibility in direct sunlight. I do believe
that CRT are brighter. I know they used to be, by a non trivial
ammount. Might e-mail a merchant marine officer school and see what
the big boys use.
Furano radar a good brand, and is popular for both boats and big
ships. Someone sells a radar that works with a PC for a display. All
the radar electronics are up by the antenna. Radar can be had for less
than two grand, and so I plan to put it on my 22 foot runabout. The
depth finder is nearly useless, except for spotting fish, the entire
lake is the same depth. Maybe that is one reason so many of them are
simply called 'fishfinders.'

They make remote mounted compasses that have no moving parts except
the indicater needle. Had one like that on a 1944 built biplane. You
can make a six foot [folding?] mast for it if you have to.

The compass is always the important issue. It and the clock are the
most important instruments on any boat. People even set their clocks
with short wave radio signals. I suppose you could check a compass
with a GPS.

Casady