1.4: Seasonal Sun Position

Astronomy 10: The Solar System (Workbook) · LibreTexts

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    From LibreTexts, under CC BY 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    1.4.1 Time of Day

    Model

    This is a view of the Earth where we are looking down at the North Pole. The Earth spins counterclockwise, carrying the person with it.

    Earth viewed from above the North Pole with people A–D and the Sun showing day and night sides.

    Earth viewed from above the North Pole with people A–D and the Sun showing day and night sides.

    1. Which person(s) (A, B, C, or D) is/are experiencing day time? Explain your reasoning.
    2. Which person(s) (A, B, C, or D) is/are experiencing night time? Explain your reasoning.
    3. Which person is experiencing each time of day? Label the times next to the letters.
      • 6AM
      • Noon
      • 6PM
      • Midnight
    1. Draw a sun figure on the arc to represent the location of the sun in the local view of the sky at each time. Explain your reasoning under the figure.

    6AM

    Southern Altitude and Azimuth Sky Dome with Sun Path plotted as an arc in the southern sky.

    Noon

    Southern Altitude and Azimuth Sky Dome with Sun Path plotted as an arc in the southern sky.

    6PM

    Southern Altitude and Azimuth Sky Dome with Sun Path plotted as an arc in the southern sky.

    Midnight

    Southern Altitude and Azimuth Sky Dome with Sun Path plotted as an arc in the southern sky.

    1. At what time is the position of the sun at its highest point in the sky? What direction do you need to look to see the sun at this time?
    2. At sunrise, what direction do you need to look to see the sun?
    3. At sunset, what direction do you need to look to see the sun?
    4. At both sunrise and sunset, draw a dashed circle on the sky to show the location of the sun one hour later (7AM and 7PM). Label those dashed circles with their times. Then, add these people as stick figures to the original model and label them with their times.

    1.4.2 Solar Altitude by Latitude

    Model

    Use the simulation as a source of evidence for this activity. The sun rays show the position of the sun at noon on the specified day of the year. Open the simulation at:

    https://astro.unl.edu/classaction/animations/coordsmotion/eclipticsimulator.html

    1. Set the month to March. Adjust the latitude to the values in the table below and record what you observe at that latitude.
    Latitude and Altitude of the Sun
    Latitude Altitude of the Sun
    20° N
    40° N
    60° N
    20° S
    40° S
    60° S
    1. How does your latitude affect the altitude of the sun that you observe at noon in the month of March?
    2. Construct an equation for the altitude of the sun (\(h\)) and show that your equation works with two different entries in the table above.

    \( h = \)

    1.4.3 Seasonal Solar Altitude

    Continue to use the simulation at:

    https://astro.unl.edu/classaction/animations/coordsmotion/eclipticsimulator.html

    1. Set your latitude to 40° N. What does your equation say the solar altitude should be at noon?
    2. Change the month. Is your equation still valid? If not, can you find another month (besides March) that your equation is valid for?
    3. Change the month and fill in the table based on your observations. Identify how many degrees higher (+) or lower (-) the measured altitude is compared to your calculated solar altitude.
    Seasonal Solar Altitude Observations
    Month Measured Altitude Degrees +/- Predicted
    December
    March
    June
    September
    1. Summarize your results. What pattern do you notice throughout the year? How might this relate to seasons (Summer, Fall, Winter, Spring)?

    Summary

    The altitude of the sun at noon from your latitude changes throughout the season because the Earth is tilted.

    The altitude of the sun at noon from your latitude changes throughout the season because the Earth is tilted.

    The measured altitude is given by the equation:

    \( h = \)

    The seasonal tilt ranges from \( \,^\circ \) to \( \,^\circ \).

    1.4.4 Seasonal Light

    Model

    Continue to use the simulation at:

    https://astro.unl.edu/classaction/animations/coordsmotion/eclipticsimulator.html

    1. Set the latitude to 37° N. Switch back and forth between December and June and fill out the table to compare the differences about the sun’s rays during these two months.
    Seasonal Light Comparison
    December June
    Altitude of the sun is (higher / lower)
    Rays are (more vertical / more horizontal)
    Rays are (closer together / farther apart)
    Person is (closer / farther) from shadowed part of Earth

    This page titled 1.4: Seasonal Sun Position was last modified on Sat, 01 Aug 2026 14:37:29 GMT and is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Andrew Totah-McCarty.