Since it is sunset, we are looking in a westward direction, so north is to the right.  The Sun is setting with a northward component (imagine sliding down the line connecting the Sun images, you would be sliding toward the north as the Sun set). Declination circles slope northward in the Northern Hemisphere.

This photograph was taken in central North Carolina (latitude ~ 36ºN) in the early 1980s with a film camera.  If the film had not moved slightly with each rewind of the camera, we could have estimated the location’s latitude, which is equal to the angle of the Sun’s motion from vertical.

Since it is sunrise, we are looking in an eastward direction and north is to the left.  The plane of the sun’s motion is sloping northward, so it’s in the Northern Hemisphere.

This movie was taken on Cape Cod at a latitude of 42ºN, so the Sun’s motion at sunrise is 42º from vertical or 48º from the horizon (90º – 42º).

Thomas Ysrael from Tamuning, Guam (latitude = 13.5 ºN), made the timelapse movie of this beautiful sunset.

Notice that as the sun sets, it is moving slightly to the right each frame.  Since sunset occurs toward the west (rarely is it exactly west), north is to the right in the movie.  An easy way to know what hemisphere while watching a sunset is that the sun moves somewhat northward if in the northern hemisphere, and southward when in the southern hemisphere.  And if standing on the Equator?  The sun sets perpendicular to the horizon.  And if at the North or South Pole?  The sun stays at the same altitude above the horizon as it makes a complete circle in the sky.

In the movie, if you measured the angle the sun sets relative to the horizon, it would be 90º – 13.5º or 76.5º

Note that the sun is not moving; we are watching the effects of Earth rotating.

Want to make your own timelapse?  There are several free apps for your smartphone.  The key is to keep your camera vertical and stationary as you film.  If possible, a tripod is handy in keeping your phone stable and perpendicular. Start at least a half an hour before sunset. If filming a sunrise, allow for a half an hour of filming after the sun is above the horizon.  

Finally, when you go to a remote tropical beach to watch a romantic sunset, take a flashlight with you! The sun will set very quickly below the horizon, and you have an unexpectedly short twilight compared to what you are used to if you live poleward of 30º latitude.  The romance soon disappears as you stumble along in the dark.

You needed to convert the information from the N-S declination circle to a view of the declination circle from above.

The sun is shining nearly directly on your right side as you depart, and it should be roughly 30º in front of your right shoulder on your return at 6 PM (18 in the diagram).

The sunbeams for the hourly positions are drawn to make it easier to visualize how the sun is hitting you as you walk.

Create a declination circle for K2 at the summer solstice, June 21, and see which times of the day are north of K2. If you like, create an overhead view of the declination circle to visualize when K2 will be illuminated.

A few hours before sunrise and sunset between mid-April and the end of August (there are more dates where the Sun is slightly north of east at sunrise and north of west at sunset and there is much less time available to shoot).

• Humans have been using the apparent motion of the Sun as a compass, clock, and calendar for millennia.  And we can use it for so much more today.

An overview of how the Sun’s energy is generated and how its thermal radiation illuminates and heats Earth.

• Overview: The Sun illuminates the spherical, rotating planets orbiting it.
• Obliquity and Earth’s Illumination: Obliquity is the angle between the planes of the Earth’s equator and its orbit around the Sun.
• Declination, Latitude, & Earth Illumination: Solar declination is the angle between the Sun’s rays and the plane of the Earth’s Equator.  Its value depends on where Earth is in its orbit around the Sun.
• Astronomical Seasons & Illumination: Astronomical seasons are based on the orientation of Earth’s axis of rotation to the Sun, which determines the amount of illumination between the Northern and Southern Hemispheres.

• Overview: Even though an area is illuminated by sunlight, there can be quite a range of energy interacting with the surface.
• Sun Angle and Beam Concentration: If every beam of sunlight reaching Earth has the same amount of energy, why do some areas warm up more than others?
• Diurnal Heating: Diurnal heating is the temperature change over 24 hours.  When sunlight shines on the ground, it warms.  Two critical factors that determine the amount of heating deal with the Sun’s illumination.
• Seasons: Earth experiences astronomical seasons due to its obliquity.
• Climate Regimes: Climate regimes are an extension of diurnal heating and seasons, but the time frame is now years. 

• Overview: Drawings of declination circles contain the visual and numerical information to understand and predict the Sun’s motion across the sky.
• Declination Circles 101: Draw a declination circle with just a ruler and protractor/compass to quickly and accurately know the Sun’s position in the sky at any day and time of the year for any location on Earth.
• Drawing Declination Circles: Declination circles are quite easy to draw by hand.
• Interpreting Time on Declination Circles: Accurately estimate the time of day using the Sun’s location in the sky.
• Sunrise, Sunset, & Twilight: Calculate the timing and duration when the Sun is at or near the horizon.
• Solar Time, Angle, & Position: The sun’s angle and direction to the local horizon define the Sun’s position in the local sky.  Explore how to use declination circles to calculate the Sun’s position at any solar time anywhere in the world on any day of the year.
• Changing Views of Declination Circles: Use the web app View Declination Circles to explore three common views of declination circles to identify their strengths, limitations, and applications.  Then learn how to go from one view to another.
• Using Declination Circles: Humans have been using the apparent motion of the Sun as a compass, clock, and calendar for millennia.
  • Using Sundials: Humans have been using the Sun’s position to navigate and tell the time, day, and season for millennia.  Sundials create shadows that make it easier to do these tasks.