A very basic question about perspective

Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick

Every Lens was focused on the sun. Thus the sun was made to fill the
available size of each picture. Just at that moment the sun developed a
spot (venus).

If I took a picture of your face. Your face would fill the entire
photo...and a spot on your cheek just happened to be there.

"Rick" wrote in message
...
Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick

Every Lens was focused on the sun. Thus the sun was made to fill the
available size of each picture. Just at that moment the sun developed a
spot (venus).

If I took a picture of your face. Your face would fill the entire
photo...and a spot on your cheek just happened to be there.

"Rick" wrote in message
...
Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick

Sorry I still don't understand. Using your analogy, if you were
small enough to be sitting on a spot on my cheek, my face would
seem huge -- it would fill up an entire hemisphere of your view.

Rick

"Aunt Buffy" wrote in message news:3XdCc.47$e15.33@newsfe5-win...
Every Lens was focused on the sun. Thus the sun was made to fill the
available size of each picture. Just at that moment the sun developed a
spot (venus).

If I took a picture of your face. Your face would fill the entire
photo...and a spot on your cheek just happened to be there.

"Rick" wrote in message
...
Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick

Sorry I still don't understand. Using your analogy, if you were
small enough to be sitting on a spot on my cheek, my face would
seem huge -- it would fill up an entire hemisphere of your view.

Rick

"Aunt Buffy" wrote in message news:3XdCc.47$e15.33@newsfe5-win...
Every Lens was focused on the sun. Thus the sun was made to fill the
available size of each picture. Just at that moment the sun developed a
spot (venus).

If I took a picture of your face. Your face would fill the entire
photo...and a spot on your cheek just happened to be there.

"Rick" wrote in message
...
Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick

On Wed, 23 Jun 2004 02:52:24 -0700, "Rick" wrote:

Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick


It is a matter of perspective. Suppose you are looking at both
someone about 20 feet away and your own thumb about 6 inches from your
nose. Your thumb would look bigger than the guy!

This is what was happening during the transit: Venus was at ( about! )
40 millions Kms while the Sun is about 150 millions Kms away, from the
surface of Venus, the Sun does look about 30% bigger than here on
Earth. If Venus would be at the same distance as the Sun, it would
look about 4 times smaller.

Have a nice day!

Benoît...

On Wed, 23 Jun 2004 02:52:24 -0700, "Rick" wrote:

Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick


It is a matter of perspective. Suppose you are looking at both
someone about 20 feet away and your own thumb about 6 inches from your
nose. Your thumb would look bigger than the guy!

This is what was happening during the transit: Venus was at ( about! )
40 millions Kms while the Sun is about 150 millions Kms away, from the
surface of Venus, the Sun does look about 30% bigger than here on
Earth. If Venus would be at the same distance as the Sun, it would
look about 4 times smaller.

Have a nice day!

Benoît...

"Rick" wrote in message
...
Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick

The sun looks small because it's far away. If Venus is far away it also
looks small.

If you are on Venus then Venus is close by and it'll look big. The sun is
still far away, so it'll still look small again (but a bit bigger than we
see it 'coz it's closer).

Does this help?

"Rick" wrote in message
...
Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick

The sun looks small because it's far away. If Venus is far away it also
looks small.

If you are on Venus then Venus is close by and it'll look big. The sun is
still far away, so it'll still look small again (but a bit bigger than we
see it 'coz it's closer).

Does this help?

"Rick" wrote in :

Looking at all the recent Venus transit images made me wonder
about perspective. The images make it look like the sun, if it
were viewed from the surface of Venus, would fill most of the
sky. And I suppose if someone saw an Earth transit from the
surface of Mars it would look pretty much the same. Is there
some simple explanation of this phenomenon?

Rick




I call it "field compression". Every photographer who uses telephoto lenses
(and telescopes)is aware of this phenomenon of geometric optics. It looks
as if everything in the field of view is brought up to the nearly the
same distance.

In this image of the plane captured in front of the Sun during the Venus
transit, it appears dwarfed by the Sun for the same reason.
http://sci.esa.int/science-e/www/obj...objectid=35224
Passengers on that flight will tell you that the Sun did not covered most
of the sky and that it looks the same size to them as it does from the
ground. The same phenomenon applies to Venus in this same image.

Here's another with the a plane and Moon. While the telephoto lens magnify
the plane and moon many orders of magnification and see craters, the
passengers eyes still magnify only 1x and will not see craters. To them the
moon is still a small as it appears from the ground. I've seen a similar
telephoto image with a person at a distance silhouetted against a giant
full moon, but could not find it for now.

Hope this helps

Martin



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