Moonshadows: angle makes no sense.

clip...

The sheer power output of the Sun in terms of radiation is incredible
and rather than referencing the Earth's orientation to the Sun,it is
more productive to treat the Earth's motions bathing in the solar
radiation thereby working things out locally.

http://www.climateprediction.net/ima...ges/annual.gif

The oscillation of temperature bands over the course of an annual orbit
is due to the amount of time a location spends in the Earth's orbital
shadow and in direct radiation more than the contemporary way of seeing
only the inclination of solar radiation striking the Earth.

In short,the Earth does not tilt towards and away from the Sun as
though the Sun were a distant flashlight in causing hemispherical
weather patterns (seasons),what occurs is thaat the Earth's orbital
orientation changes against fixed axial orientation thereby altering
the length of time a location spends in solar radiation (day) or in
the orbital shadow (night) and consequently affecting heating patterns
for that location.

You stumbled into an excellent astronomical way to appreciate the
change in the Earth's orbital orientation against fixed axial
orientation but it may take a long while to drop the uneccessary
referencing the Earth's axial orientation to the Sun ,start
appreciating the incredible power output of our Sun and work with
motions and orientations locally.

Here are four images of the change in orbital orientation against fixed
axial orientation,the only way to approach the answer you require.If
the change in the Earth's orbital orientation looks a bit off-putting
then just keep things local and it will all become clear.It is alsop
extremely important for climate studies -

http://upload.wikimedia.org/wikipedi...easonearth.png






What you describe here is only slightly related to the angular optical
illusion I'm trying to find an explanation for. I know why seasons
exist...

I'm going to articulate it better, and post the article link here.

It's pure physics/geometry......

In message ,
lid writes

What you describe here is only slightly related to the angular optical
illusion I'm trying to find an explanation for. I know why seasons
exist...

Which is more than Gerald does. Please don't encourage him :-)
BTW, I've kill filed him. Were all six posts the same?

james@j wrote:
clip...

The sheer power output of the Sun in terms of radiation is incredible
and rather than referencing the Earth's orientation to the Sun,it is
more productive to treat the Earth's motions bathing in the solar
radiation thereby working things out locally.

http://www.climateprediction.net/ima...ges/annual.gif

The oscillation of temperature bands over the course of an annual orbit
is due to the amount of time a location spends in the Earth's orbital
shadow and in direct radiation more than the contemporary way of seeing
only the inclination of solar radiation striking the Earth.

In short,the Earth does not tilt towards and away from the Sun as
though the Sun were a distant flashlight in causing hemispherical
weather patterns (seasons),what occurs is thaat the Earth's orbital
orientation changes against fixed axial orientation thereby altering
the length of time a location spends in solar radiation (day) or in
the orbital shadow (night) and consequently affecting heating patterns
for that location.

You stumbled into an excellent astronomical way to appreciate the
change in the Earth's orbital orientation against fixed axial
orientation but it may take a long while to drop the uneccessary
referencing the Earth's axial orientation to the Sun ,start
appreciating the incredible power output of our Sun and work with
motions and orientations locally.

Here are four images of the change in orbital orientation against fixed
axial orientation,the only way to approach the answer you require.If
the change in the Earth's orbital orientation looks a bit off-putting
then just keep things local and it will all become clear.It is alsop
extremely important for climate studies -

http://upload.wikimedia.org/wikipedi...easonearth.png






What you describe here is only slightly related to the angular optical
illusion I'm trying to find an explanation for. I know why seasons
exist...


You do not know the reason for hemispherical weather patterns
(seasons).

Your reason is based on the Sun like a flashligh and varying the axial
tilt of the Earth,something like this -

http://www.astronomy.org/programs/se...ing-sun-sm.gif


In short,you include axial and orbital orientations into a single
homogenised packet which is why you will never come to the correct
answer.

Try keeping the Earth's motions seperate,bath the Earth in received
radiation and allow the change in orbital orientation to answer your
question.This is really easy stuff with familiarity but suit yourself
if you wish the Sun to shine like a flashlight just for you,it only
shows a lack of appreciation for our central parent star and the scale
of orbital geometry.

Go luck to you in your celestial sphere pursuit.




I'm going to articulate it better, and post the article link here.

It's pure physics/geometry......

On Mon, 04 Dec 2006 21:57:12 GMT, Jonathan Silverlight
wrote:

In message ,
writes

What you describe here is only slightly related to the angular optical
illusion I'm trying to find an explanation for. I know why seasons
exist...

Which is more than Gerald does. Please don't encourage him :-)
BTW, I've kill filed him. Were all six posts the same?

I think I will too, and ya, they were. ;-)

--jim

james@j wrote:
On Mon, 04 Dec 2006 21:57:12 GMT, Jonathan Silverlight
wrote:

In message ,
writes

What you describe here is only slightly related to the angular optical
illusion I'm trying to find an explanation for. I know why seasons
exist...

Which is more than Gerald does. Please don't encourage him :-)
BTW, I've kill filed him. Were all six posts the same?

I think I will too, and ya, they were. ;-)

--jim

I am looking at the contemporary images of the Earth from space which
dictate that the orbital orientation of the Earth,due to the Earth's
orbital motion,changes against axial orientation which is a product of
the Earth's rotation.

http://upload.wikimedia.org/wikipedi...easonearth.png

Maybe there is some unknown disease why people cannot adapt to the
actual images and feel it necessary to make the Earth vary its tilt to
the Sun to explain the seasons but there is nothing difficult in
recognising what changes and what remains fixed.

Using Io's shadow to affirm the Earth's orbital motion along with
Jupiter's around the Sun is entirely new and there is nothing difficult
about that either.I look at your excellent question which in other eras
would produce an expansive discussion but watch it wither under a
blizzard of useless wordplays and mediocrity.

Again.good luck to you and your celestial sphere mentality.a 17th
century conception which tries to reduce the great natural cycles to a
celestial sphere peep show and where men can't even find their way
through simple astronomical concepts.

On Sun, 03 Dec 2006 00:35:49 GMT,
wrote:

This has fascinated me for a while; I must be overlooking something.

Seemingly the sun's rays hit the moon at an angle that often don't
make sense when considering the sun has set. See
http://www.jamesphotography.ca/moon.jpg which was shot about 1/2 an
hour following sunset. The camera was level.

We're observing 3-d objects in 3-d space, so distances make no
difference when analysing this from a geometry standpoint. And what
we're looking at isn't some curved inside-of-a-bowl phenomena; again,
it's all 3 dimensional.

Insights?



--jim


As promised...

http://www.jamesphotography.ca/moon/moon.html



--jim

james@j wrote:
On Sun, 03 Dec 2006 00:35:49 GMT,
wrote:

This has fascinated me for a while; I must be overlooking something.

Seemingly the sun's rays hit the moon at an angle that often don't
make sense when considering the sun has set. See
http://www.jamesphotography.ca/moon.jpg which was shot about 1/2 an
hour following sunset. The camera was level.

We're observing 3-d objects in 3-d space, so distances make no
difference when analysing this from a geometry standpoint. And what
we're looking at isn't some curved inside-of-a-bowl phenomena; again,
it's all 3 dimensional.

Insights?



--jim


As promised...

http://www.jamesphotography.ca/moon/moon.html



--jim

"The moon's angle of illumination is slightly difficult to make out,
but the shadow in the lower left side can sometimes be much more
pronounced. It's still obviously in the lower left side. Imagine line
"A" in this picture pulled towards you, so it points over your right
shoulder from the center of the moon... this is the actual three
dimensional representation, and still contradicts basic geometry when
considering the light source has disappeared below the horizon"

http://www.jamesphotography.ca/moon/moon.html

You really Do believe that the Sun is a flashlight that disappears over
the horizon !,but at least you have plenty of company.

Until you become familiar with the sheer power of the received
radiation right ,you are unlikely to get the answer you are looking
for.You get the same changes in the moon's shadow orientation as seen
from Earth by dropping the silly reference to the diameter of the Sun.

I am at a loss why you people insist on retaining ideas which should
have been jettisoned many years ago,the images of the Earth from space
signifying the Earth's axial and orbital motions clearly resolve the
issues.

I've managed to reproduce the effect in a 3D imaging program, POV-Ray,
but only when the Moon is slightly gibbous. When it's exactly first
quarter the illumination is as you'd expect it.

POV-Ray is a well established program that has been used by huge numbers
of people who complain bitterly on the associated newsgroups about its
slightest flaw, and they've never mentioned problems with illumination
directions. So I consider it trustworthy ion this respect.

Here's a still image of the Moon, illuminated by a Sun that's out of
frame on the horizon.
http://www.econym.demon.co.uk/temp/moon.jpg

And here's an animation panning round from the Moon to the Sun.
http://www.econym.demon.co.uk/temp/moon.gif

I've added one cylindrical ray from the Sun to the moon. It looks fatter
at the Moon end because that end is about 372 times closer to the
camera. All frames are conventional perspective views.

The light ray is a perfectly straight line in each individual frame, but
the angle of the line varies from frame to frame.

You can imagine how the effect works if you consider a pair of parallel
lines that stretch from horizon to horizon and pass just North of the
point where you're standing. When you look West, the lines appear to be
straight lines that converge at a point on the western horizon. When you
look East, the lines appear to be straight lines that converge at a
point on the eastern horizon. When you look North they appear to be
straight parallel lines. Whichever direction you look, or take a
photograph, the lines are perfectly straight in each individual image,
but as you turn your head or camera, the angle between those straight
lines changes.

My killfile appears to have eaten 10 of the postings in this thread, so
I apologise if any of this duplicates what's been said in the posts that
I've not read.

--
Mike Williams
Gentleman of Leisure

In article ,
Mike Williams wrote:

The light ray is a perfectly straight line in each individual frame, but
the angle of the line varies from frame to frame.

It may help to consider that the ray is a straight line, but the
horizon is a circle, so the ray can't be at the same angle to the
horizon in all directions.

-- Richard

--
"Consideration shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

On Tue, 05 Dec 2006 08:38:55 GMT, in uk.sci.astronomy ,
wrote:

On Sun, 03 Dec 2006 00:35:49 GMT,
wrote:

This has fascinated me for a while; I must be overlooking something.

Seemingly the sun's rays hit the moon at an angle that often don't
make sense when considering the sun has set.

it might be instructive sometime for you to draw the path of two
parallel rays passing overhead from one horizon to the other, taking
into account perspective. Their path does _not_ appear straight.

--
Mark McIntyre