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Old March 16th 05, 03:55 AM
§ Dr. Artaud §
 
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Actually, I had been eyeballing those tiny TVs that Radio Shack sells,
the handheld type. The prices seemed reasonable. Problem is, as you
state, the transmission mode will soon be HD, and these TVs will become
technological paperweights, therefore I did not purchase. I can't
imagine carrying a cable TV converter size box to receive HD signals on
my handheld TV.

Of the handheld TVs, as far as I know, the principle of angular diameter
applies. Consider the moon and the sun. Concerning angular diameter,
they (from earth), appear the same size (plus or minus a very small
amount). Because of this, the moon is often able to fully eclipse the
sun. Quite a nice match up, size wise.

http://www.rc-astro.com/composite/sun_moon.htm

http://www.photoastronomique.net/pho...20003-16_16-25


Look here, the third photo set down, a comparison of the Sun, Jupiter,
and the Earth, with the Earth as just a speck.

http://www.hartrao.ac.za/other/howfar/howfar.html

Obviously the Sun is massive, yet it appears to us to be the same size
as the moon. Same with the Handheld TVs (no, they don't appear the same
size as the moon ;-), you can have your own personal Big Screen TV for
under $200. (actually the little TV, held close, giving the same angular
diameter as a considerably larger TV across the room).

Look at your TV across the room, hold a ruler at arms length, place one
side of the ruler on the left of the TV screen, place your thumb at the
point on the ruler where the right side of the screen is. A TV the size
that your ruler is indicating, held at arms length, is the same size
image in your mind as the TV across the room. I'm sure that some of you
have those gigantic TVs, this may be a little harder to visualize, but
the principle is valid.


http://www.celestron.com/education/binbasic.htm

From what I know of optics, a 10 power (10X) binocular increases the
angular diameter of the object viewed by 10 times, it does not make it
appear 10 times closer (it makes it appear even closer than 10 times).
The example that I read was to stand 2 feet from the wall, look at the
wall, now step forward one foot. You are now at half the distance, does
the wall appear twice as big? No.

But supposedly, to view the wall through a 2X binocular would make it
appear closer than 2 times, as the angular diameter has been doubled. A
cursory experiment with a ruler held at arms length, and the angular
diameter of the laptop screen confirms this. Half the distance does not
yield twice the size.

Anyway, don't trust searches on the internet, as they have simplified
the concept, using the 10 times the size and 10 times closer analogy.

I digress, but it was fun.

Regards

Dr. Artaud


In my TV Predictions email newsletters I get from Philip Swann,my
newsletter I received yesterday has an article about Congress is
working on making all U.S.A.tv stations transmit only HDTV signals by
the end of next year or soon after the end of next year.Read about it
at, www.tvpredictions.com
cuhulin

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