1432: "The Lowell Observatory"

HistoryPodcastScience
Written By JC

Interesting Things with JC #1432: "The Lowell Observatory" – On a hill above Flagstaff, one man’s private telescope reached for the unknown, and found it.

Curriculum - Episode Anchor

Episode Title: The Lowell Observatory
Episode Number: 1432
Host: JC
Audience: Grades 9–12, college intro, homeschool, lifelong learners
Subject Area: Astronomy, History of Science, Physics

Lesson Overview

Students will explore the founding and legacy of the Lowell Observatory and its role in shaping modern astronomy. Through this lesson, learners will:

  • Define the purpose and function of an astronomical observatory.

  • Compare historical and modern astronomical technologies.

  • Analyze the significance of the discovery of Pluto and its impact on scientific progress.

  • Explain how individuals like Percival Lowell and Clyde Tombaugh contributed to our understanding of the solar system.

Key Vocabulary

  1. Observatory (ob-ZUR-vuh-tor-ee) — A facility equipped with telescopes and instruments for observing celestial events.

  2. Refractor Telescope (ree-FRAK-tur TEL-uh-skope) — A telescope that uses lenses to gather and focus light from distant objects.

  3. Planet X (PLAN-it eks) — A hypothetical planet believed by Lowell to exist beyond Neptune.

  4. Blink Comparator (blink kom-PAIR-uh-tur) — A device used to compare two photographic plates taken at different times to identify moving celestial objects.

  5. Pluto (PLOO-toh) — The celestial body discovered in 1930 at Lowell Observatory, once considered the ninth planet in our solar system.

Narrative Core

Open:
In 1894, on Mars Hill overlooking Flagstaff, Arizona, Percival Lowell built a place to look deeper into the night sky—a personal observatory aimed at uncovering cosmic mysteries.

Info:
Lowell’s observatory stood 7,200 feet above sea level for clearer skies. He funded it himself, importing a 24-inch Clark Refractor telescope made by Alvan Clark & Sons, housed in a hand-cranked wooden dome that still operates today.

Details:
Lowell searched for canals on Mars and a mysterious “Planet X” that might explain Neptune’s orbital irregularities. Though he didn’t find it, the observatory continued his mission. In 1930, assistant Clyde Tombaugh used a blink comparator to discover Pluto—3.5 billion miles from the Sun.

Reflection:
The Lowell Observatory later contributed to mapping the Moon for Apollo missions and studying cosmic expansion, embodying the spirit of discovery Lowell began over a century ago.

Closing:
These are interesting things, with JC.

Historic refracting telescope inside Lowell Observatory’s wooden dome in Flagstaff, Arizona, aimed upward under warm interior lighting.

Transcript

Back in 1894, up on a rise called Mars Hill overlooking Flagstaff, Arizona, a man named Percival Lowell (PUR-suh-vul LOW-uhl) built a place to look deeper into the night sky. The Lowell Observatory sits at about 7,200 feet, or 2,195 meters, above sea level. Lowell chose that high, dry patch of land for one reason: clear skies.

He paid for the whole thing himself, spending around twenty thousand dollars at the time, roughly seven hundred thousand today, to build the dome, ship in the glass, and mount the telescope.

That main telescope, the Clark Refractor, was made by Alvan Clark & Sons in Massachusetts. Its lens is 24 inches, or 62 centimeters, across. The wooden dome that shelters it measures about thirty-two feet wide, just under ten meters. Even now, more than a century later, it still works with the same smooth hand crank that Lowell used to turn the roof and follow the stars.

Lowell was sure Mars had canals, and that there was another planet tugging on Neptune’s orbit, a world he called Planet X. He never found it, and he passed away in 1916 still searching. But his observatory carried on.

In 1930, a young assistant named Clyde Tombaugh (KLIDE TOM-baw) spent nights comparing glass photographs of the same piece of sky, one after another, using a simple tool called a blink comparator. On one pair of plates, he spotted a faint moving dot. That dot turned out to be Pluto, nearly three and a half billion miles, or 5.8 billion kilometers, from the Sun.

That discovery put Flagstaff on every map in astronomy. Years later, Lowell Observatory helped map the Moon for the Apollo missions and joined the research that showed our universe is expanding faster than anyone expected.

It’s still an active observatory today. The Clark Telescope is open to the public, and down the road, the staff now works with the much larger Discovery Channel Telescope, a 4.3-meter mirror, about 169 inches across.

But even with all that progress, the heart of Lowell Observatory hasn’t changed. It’s still that quiet wooden dome on Mars Hill where one man’s belief in the unseen opened a window to the farthest edge of the solar system.

These are interesting things, with JC.

Student Worksheet

  1. Why did Percival Lowell choose Mars Hill for his observatory?

  2. What is unique about the Clark Refractor telescope?

  3. Who discovered Pluto, and what tool did he use?

  4. Describe one modern contribution of the Lowell Observatory.

  5. Reflect: How does Lowell’s story illustrate the importance of persistence in science?

Teacher Guide

Estimated Time: 45–60 minutes

Pre-Teaching Vocabulary Strategy:
Use visual aids (images of telescopes, observatories, and Pluto) to introduce key terms before the lesson.

Anticipated Misconceptions:

  • Students may assume Lowell discovered Pluto himself.

  • Some may think the observatory is no longer active—clarify its modern research role.

Discussion Prompts:

  • What drives people like Lowell and Tombaugh to search for the unknown?

  • How do technological advances change our understanding of space?

Differentiation Strategies:

  • ESL: Provide a vocabulary word bank with images.

  • IEP: Allow extended time for reading and writing.

  • Gifted: Assign a research extension on other historical observatories.

Extension Activities:

  • Create a scaled model of the solar system.

  • Research the process of planet classification (Pluto’s reclassification).

Cross-Curricular Connections:

  • Physics: Optics and light refraction.

  • History: Early 20th-century scientific exploration.

  • Technology: Evolution of astronomical instruments.

Quiz

  1. Where is the Lowell Observatory located?
    A. Tucson, Arizona
    B. Flagstaff, Arizona
    C. Pasadena, California
    D. Boulder, Colorado
    Answer: B

  2. What telescope did Percival Lowell use?
    A. Hubble Telescope
    B. Clark Refractor
    C. Mount Wilson Reflector
    D. Discovery Channel Telescope
    Answer: B

  3. Who discovered Pluto?
    A. Percival Lowell
    B. Edwin Hubble
    C. Clyde Tombaugh
    D. Galileo Galilei
    Answer: C

  4. What tool helped identify Pluto’s movement?
    A. Spectroscope
    B. Blink Comparator
    C. Microscope
    D. Compass
    Answer: B

  5. Which modern project is Lowell Observatory involved in?
    A. James Webb Space Telescope
    B. Mapping the Moon for Apollo missions
    C. SETI radio arrays
    D. Deep Sea Observatory
    Answer: B

Assessment

  1. Explain how the Lowell Observatory contributed to the discovery of Pluto.

  2. Compare the scientific tools used by Lowell and modern astronomers.

3–2–1 Rubric:
3: Accurate, complete, thoughtful response with examples.
2: Partial explanation with missing or unclear details.
1: Inaccurate or vague response lacking key facts.

Standards Alignment

NGSS (Next Generation Science Standards)

  • HS-ESS1-4: Use mathematical or computational representations to predict the motion of orbiting objects in the solar system.

  • HS-ETS1-2: Design and evaluate solutions to real-world problems using engineering principles (e.g., telescope design).

CCSS (Common Core State Standards – Literacy in Science & Technical Subjects)

  • RST.9-10.2: Determine the central ideas of a scientific text.

  • WHST.11-12.2: Write informative texts to examine and convey complex ideas clearly.

C3 Framework (Social Studies)

  • D2.His.14.9-12: Analyze multiple causes and effects in historical events and developments (scientific discoveries).

Cambridge IGCSE Physics (International Equivalent)

  • Section 1.6: Describe how telescopes gather and focus light to form images.

  • Section 7.2: Explain how astronomical observation contributes to understanding planetary motion.

Show Notes

This episode of Interesting Things with JC explores the story of the Lowell Observatory—founded by Percival Lowell in 1894 in Flagstaff, Arizona. The observatory became a hub for major astronomical discoveries, including the identification of Pluto by Clyde Tombaugh. Beyond its historical importance, Lowell Observatory remains active in research, bridging early celestial exploration with modern astrophysics. In the classroom, this episode provides a vivid case study of scientific curiosity, technological progress, and the enduring value of persistence in scientific discovery.

References

JC https://jimconnors.org
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