Astrolabe TW en short

Summary

This video introduces an astrolabe, a historical astronomical device on loan from the Oxford Museum of History. The presenter explains its various components, including the Mater, Reit, and rule, demonstrating how they work together to model the night sky. He shares a personal story about building a paper astrolabe for his thesis and highlights the significant value of real astrolabes. Using the star Deneb as an example, the presenter walks through the process of using the astrolabe to measure star altitude, align it with the sky model, and ultimately determine time.

Takeaways

• 🔭 The video is about an astrolabe, a historic astronomical device.
• 🏛️ The astrolabe in the video is on loan from the Oxford School of Museum of History.
• ⚙️ The astrolabe consists of multiple components like the Mater, Reit, and scales for various astronomical calculations.
• 🕸️ The spiderweb pattern on the back of the astrolabe corresponds to local sky coordinates.
• 📜 The presenter mentions building a paper astrolabe for their thesis.
• 🕰️ The astrolabe shown is a replica of a 15th-century device and is valued at the price of several MacBook Pros.
• 🏡 An original astrolabe could cost as much as several houses or even an entire block.
• 🌌 To use the astrolabe, the first step is selecting a star in the night sky, such as Deneb in the summer triangle.
• 🧭 The presenter demonstrates how to measure the altitude of a star with the astrolabe and align it with the sky model.
• ⏳ Finally, the astrolabe can be used to tell time by aligning the rule with the date line after setting the altitude.

Q & A

What is an astrolabe, according to the speaker?

An astrolabe is an ancient instrument used for making astronomical calculations, such as measuring the altitude of stars and determining the time based on the position of celestial objects.

Where is this particular astrolabe on loan from?

This particular astrolabe is on loan from the Oxford School of the Museum of History.

What are the key components of the astrolabe described in the script?

The key components of the astrolabe include the Mater (the main body with scales), the Reit (a movable part representing the sky), and various measuring tools and scales on the back.

What does the spiderweb pattern on the back of the astrolabe represent?

The spiderweb pattern on the back of the astrolabe corresponds to the local coordinates in the sky.

How does the speaker describe the value of the astrolabe?

The speaker humorously compares the value of a replica of a 15th-century astrolabe to the price of about three MacBook Pros, while stating that a real one would cost as much as several houses and possibly even a school or church.

What star is used as an example for measuring time in the demonstration?

The speaker uses the star Deneb, part of the summer triangle, as an example in the demonstration.

What is the first step in using the astrolabe to tell time at night?

The first step is to select a star in the night sky, such as Deneb.

How is the altitude of a star measured using the astrolabe?

The altitude of a star is measured by holding the astrolabe up, sighting the star, and reading its altitude from the device's scale.

How does the astrolabe help create a model of the sky?

By moving the Reit so that the altitude of the star corresponds to the scale on the back of the device, the astrolabe aligns with the real sky, creating a model of the universe in the user's hands.

What is the final step in determining the time using the astrolabe?

The final step is to move the rule to a date line, which then indicates the time.