sunrise during summer time

hi,

i was camping in yellowstone NP three weeks ago. for the first time in
quite a while, i was able to observe sunrise and starry night. one
thing i noticed is that by comparing the location of Polaris at night
and that of the sunrise in the morning, i noticed they're in the same
general direction. later on, when i came back from the trip, i found
out at that location(details below), sun is rising from NE to E
direction, instead of East

can someone explain to me why sun is rising from NE instead of East in
summertime?

Grant Village at Yellowstone:
latitude: 44=A1=E3 23.64' N
longtitude: 110=A1=E3 33.35' W
timezone: -7 hours
=20
altitude: 8000ft (2600 meter)
time: 7/06/2005 11pm ~ 7/07/2005 6am

wrote:

i was camping in yellowstone NP three weeks ago. for the first time in
quite a while, i was able to observe sunrise and starry night. one
thing i noticed is that by comparing the location of Polaris at night
and that of the sunrise in the morning, i noticed they're in the same
general direction. later on, when i came back from the trip, i found
out at that location(details below), sun is rising from NE to E
direction, instead of East

can someone explain to me why sun is rising from NE instead of East in
summertime?


It's a little hard to explain without diagrams, but the phenomenon is
part of what makes the seasons. Since the plane of the Earth's
equator is tilted about 23°26' from the plane of its orbit around the
Sun, as the planet makes its annual orbit the declination (angular
distance from the celestial equator) of the Sun changes accordingly.
At the vernal and autumnal equinoxes it's on the equator, with a
declination of 0°; on these dates it will appear to rise more or less
due East, climb to an altitude equal to the colatitude of the
observer, and set due West, taking (just about) exactly twelve hours,
half the day.

Grant Village at Yellowstone:
latitude: 44¡ã 23.64' N
longtitude: 110¡ã 33.35' W
timezone: -7 hours

altitude: 8000ft (2600 meter)
time: 7/06/2005 11pm ~ 7/07/2005 6am

Since your colatitude is about 45°36', that's how far above the
southern horizon (ignoring the mountains!) the Sun appeared at noon
on March 21; its diurnal path was half a great circle, tilted 45°36'
to the horizon around an axis passing through the east and west
points (again, I refer to the geometrical horizon such as would be
seen at sea or on the prairies). As spring progressed into summer,
the declination of the Sun increased, rapidly at first then levelling
off. Peaking at noon on the June solstice, it was 23°26' north of the
equator, putting your noonday Sun at about 69° above the horizon, 21°
from the zenith. (By July 6-7 it was only a bit lower again.)

Now picture what has happened to the Sun's diurnal arc: the Earth's
rotation carries the Sun's position around a *small* circle,
comparing to the celestial equator exactly as the Tropic of Cancer
does to the geographic equator. Since it's parallel to the equator,
the point where it crosses the prime vertical in the East is well
above the horizon; likewise when the Sun reaches due West around 6 PM
it hasn't yet set. So the day is considerably longer than the night,
and the rising and setting points are well to the north of an
east-west line.

To an observer on the Arctic Circle, the equator is tilted only
23°26' above the horizon. From there, on the summer solstice the
Sun's diurnal arc is entirely above the horizon, just touching it in
the North at midnight. For most of the summer it never gets truly
dark at high latitudes, as between sunset and dawn the Sun remains
close enough to the horizon to provide twilight illumination.

A nicely designed site for explaining the seasonal behaviour of the
Sun's position (focusing on the Equation of Time), demonstrated with
QuickTime animations, may be found at

http://www.analemma.com.

--
Odysseus

In article . com,
wrote:

i was camping in yellowstone NP three weeks ago. for the first time in
quite a while, i was able to observe sunrise and starry night. one
thing i noticed is that by comparing the location of Polaris at night
and that of the sunrise in the morning, i noticed they're in the same
general direction. later on, when i came back from the trip, i found
out at that location(details below), sun is rising from NE to E
direction, instead of East

can someone explain to me why sun is rising from NE instead of East in
summertime?

Well, think of it this way: in summer the Sun is above the horizon
longer. The Sun appears to travel one full revolution around you in
24 hours. In 6 hours it appears to travel from south to west. So if
the SUn is above the horizon more than 6 hours after (solar) noon, it
must set northward of west.

Let's go to the extreme case: suppose you're camping out right at the
north actic circle on the day of the summer solstice. Then we have
midnight sun: the sun just touches the horizon before it starts
rising again - you can consider this as if the sun sets for a moment
and then rises. Where does this happen? In the east? No. In the
west? No. It happens right in the north!

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/

On 30 Jul 2005 10:01:01 -0700, wrote:

hi,

i was camping in yellowstone NP three weeks ago. for the first time in
quite a while, i was able to observe sunrise and starry night. one
thing i noticed is that by comparing the location of Polaris at night
and that of the sunrise in the morning, i noticed they're in the same
general direction. later on, when i came back from the trip, i found
out at that location(details below), sun is rising from NE to E
direction, instead of East

can someone explain to me why sun is rising from NE instead of East in
summertime?

Grant Village at Yellowstone:
latitude: 44c 23.64' N
longtitude: 110c 33.35' W
timezone: -7 hours

altitude: 8000ft (2600 meter)
time: 7/06/2005 11pm ~ 7/07/2005 6am

There are a lot of web pages and free programs that display a
"realistic" picture of the Earth with half in shadow and half in
daylight. The position of the sun is always perpendicular to the
terminator (the line of demarcation). This line is a great circle.

Consider the vernal equinox. The line is perpendicular to the
equator. Everyone looking at the sunrise (half the locations on the
terminator) will see it due east.

But the line is not always perpendicular to the equator. As spring
progress to summer (for the northern hemisphere), the line tilts more
and more such that the north pole never enters shadow. After the
summer solstice, the line untilts back until it is again perpendicular
to the equator at the autumnal equinox.

Consider a time shortly after the vernal equinox. The line is just
slightly tilted. At the northern (and southernmost) positions on the
line, looking at the sun means looking due north (in navigation terms,
0 degrees). At the equator, it means looking just slightly north of
east (let's say 85 degrees). As you move between these positions, the
angle changes smoothly between these extremes.

As the season progresses, the line tilts more and more until the
northernmost point reaches the arctic circle at the solstice. The sun
is at its northernmost. At the equator, looking at sunrise means
looking much more north of east (approximately 67 degrees). As you
move between the equator and the arctic circle, the angle changes as
before, but everyone is now looking further north than in the previous
paragraph.

If you had been at the Grand Canyon instead of Yellowstone, the sun
still would have been north of east but not as much. Had you been at
Denali NP, it would have been much more northerly.

There are relatively simple formulas that let you see how the angle
changes as you change latitude or as you change the day. Google is
your friend.

Consider the northernmost point on the terminator. At


Remove the del for email

thank you

that's a very good explaination, i can vividly display it in my mind,
it explains

i asked the question because according to my high school geology class,
i remember the sun is always moving between
northern and southern tropic of cancer, i remeber it's 22.5 degrees.
and since yellowstone is at 45 degree latitude, i picture it from that
location, i should have observed the sun is rising from east/southeast
since i'm above the tropic of cancer. but i didn't thought 'the line
of demarcation'. now it all makes sense.

by that same token, during winter time between autumnal equinox and
vernal equinox, at northern hemsphere, i should observe the sun is
rising from southeast direction, right?

On 3 Aug 2005 16:17:30 -0700, wrote:

thank you

that's a very good explaination, i can vividly display it in my mind,
it explains

i asked the question because according to my high school geology class,
i remember the sun is always moving between
northern and southern tropic of cancer, i remeber it's 22.5 degrees.
and since yellowstone is at 45 degree latitude, i picture it from that
location, i should have observed the sun is rising from east/southeast
since i'm above the tropic of cancer. but i didn't thought 'the line
of demarcation'. now it all makes sense.

by that same token, during winter time between autumnal equinox and
vernal equinox, at northern hemsphere, i should observe the sun is
rising from southeast direction, right?

It doesn't matter which hemisphere you are in. To anyone looking, the
sunrise appears south of east during this period (except for those
folks close to the north pole where it doesn't rise at all and those
close to the south pole where it didn't set the day before).


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Barry Schwarz wrote:
On 3 Aug 2005 16:17:30 -0700, wrote:

thank you

that's a very good explaination, i can vividly display it in my mind,
it explains

i asked the question because according to my high school geology class,
i remember the sun is always moving between
northern and southern tropic of cancer, i remeber it's 22.5 degrees.
and since yellowstone is at 45 degree latitude, i picture it from that
location, i should have observed the sun is rising from east/southeast
since i'm above the tropic of cancer. but i didn't thought 'the line
of demarcation'. now it all makes sense.

by that same token, during winter time between autumnal equinox and
vernal equinox, at northern hemsphere, i should observe the sun is
rising from southeast direction, right?

It doesn't matter which hemisphere you are in. To anyone looking, the
sunrise appears south of east during this period (except for those
folks close to the north pole where it doesn't rise at all and those
close to the south pole where it didn't set the day before).


Remove the del for email

The replies are all simply incredible for their vacuousness and totally
incorrect !.

Imagining variations in Equatorial/axial tilt to the Sun or paying
attension to geocentric terms such as 'sunrise' for anything other than
civil purposes is so destructive to astronomy,climatology or any other
discipline where the motions of the Earth are required.

A thousand way to say the few same things -

The Sun does NOT vary its altitude against the Earth's Equator/axis.

The change in orbital orientation due to the Earth's orbital motion
around the Sun passing through a fixed axial orientation causes the
hemispherical illusion of axial tilt and the change in the position of
the Sun wrt to the axis/Equator.

There is absolutely no way whatsoever that responsible people would not
notice that the only way to resolve daylight/darkeness asymmetry or
cyclical seaonal variations using a global perspective would miss the
point that hemispherical axial tilt as a solution cannot be invoked
when even amateur cataloguers know that beyond the fact that axial
orientation is more or less fixed over the course of an annual orbit.

http://homepage.mac.com/tarashnat/as.../0001-08a.jpeg

Probably even more important than the day/night cycle,it is something
else to see so many who are unfamiliar with the seasonal cycle using
the astronomical/global perspective.There is no problem if people are
initially unfamiliar or uncomfortable with the correct designation
using orbital motion and orientation as the cause but the insistence to
include axial tilt or variations in the Sun's position to the
tilt/Equator is incredible for it silliness and to defend it or dither
around is a sign of incompetence.

wrote:
Barry Schwarz wrote:
On 3 Aug 2005 16:17:30 -0700, wrote:

thank you

that's a very good explaination, i can vividly display it in my mind,
it explains

i asked the question because according to my high school geology class,
i remember the sun is always moving between
northern and southern tropic of cancer, i remeber it's 22.5 degrees.
and since yellowstone is at 45 degree latitude, i picture it from that
location, i should have observed the sun is rising from east/southeast
since i'm above the tropic of cancer. but i didn't thought 'the line
of demarcation'. now it all makes sense.

by that same token, during winter time between autumnal equinox and
vernal equinox, at northern hemsphere, i should observe the sun is
rising from southeast direction, right?

It doesn't matter which hemisphere you are in. To anyone looking, the
sunrise appears south of east during this period (except for those
folks close to the north pole where it doesn't rise at all and those
close to the south pole where it didn't set the day before).


Remove the del for email

The replies are all simply incredible for their vacuousness and totally
incorrect !.

Imagining variations in Equatorial/axial tilt to the Sun or paying
attension to geocentric terms such as 'sunrise' for anything other than
civil purposes is so destructive to astronomy,climatology or any other
discipline where the motions of the Earth are required.

A thousand way to say the few same things -

The Sun does NOT vary its altitude against the Earth's Equator/axis.

The change in orbital orientation due to the Earth's orbital motion
around the Sun passing through a fixed axial orientation causes the
hemispherical illusion of axial tilt and the change in the position of
the Sun wrt to the axis/Equator.

There is absolutely no way whatsoever that responsible people would not
notice that the only way to resolve daylight/darkeness asymmetry or
cyclical seaonal variations using a global perspective would miss the
point that hemispherical axial tilt as a solution cannot be invoked
when even amateur cataloguers know that beyond the fact that axial
orientation is more or less fixed over the course of an annual orbit.

http://homepage.mac.com/tarashnat/as.../0001-08a.jpeg

Probably even more important than the day/night cycle,it is something
else to see so many who are unfamiliar with the seasonal cycle using
the astronomical/global perspective.There is no problem if people are
initially unfamiliar or uncomfortable with the correct designation
using orbital motion and orientation as the cause but the insistence to
include axial tilt or variations in the Sun's position to the
tilt/Equator is incredible for it silliness and to defend it or dither
around is a sign of incompetence.


Yes Gerald, we are surrounded by incompetents!

Scientists are stuck with using terms that carry in their root meanings
all the misguided notions of antiquity, witchcraft, homocentrism, and
anthropomorphism! No wonder they are confused!

Perhaps that's why the people at NASA can't seem to keep the Space
Shuttle in the air!

Double-A