Handbook of Nature-Study · Lesson CCXXVII · Topic 37: The stars
227. Orion
Goal: Your child can find Orion's belt and sword, Betelgeuse and Rigel, and can say what a star's color tells us.
You'll need
- A clear winter evening
- A red-covered flashlight
- Binoculars (optional)
- A nature notebook and a pencil (colored pencils if you have them)
What's in the book
The lesson has a leading thought, a method, and seven observations on Orion's place in the sky, its belt and sword, red Betelgeuse and white Rigel, the four-sided figure around them, and the story of Orion the hunter.
The lesson, step by step
When and where
Winter evenings, from December to March, about 8 or 9 p.m. Face south. Orion rises in the east in early winter evenings and is high in the south by February. Stargaze with an adult, in a dark spot away from roads, such as a back yard or a field you have permission to use. Dress warmly, bring a blanket, and cover a flashlight with red cellophane or a red balloon so your eyes stay used to the dark.
The leading thought
Orion is one of the most beautiful constellations in the heavens. It is especially marked by the three stars which form Orion's belt, and the line of stars below the belt which form the sword.
Belt and sword
How many stars in the belt of Orion? How many stars in the sword?
One "star" in the sword looks fuzzy. Look at it with binoculars if you have them.
Two great stars
Notice above the belt, about three times its length, a bright star; this is Betelgeuse. What is the color of this star?
Look below the belt and observe another bright star at about the same distance below that Betelgeuse is above. What is the color of this star?
Draw the hunter
If we connect these four stars by lines we shall make an irregular four-sided figure, fencing in the belt and sword.
What we know now
The book asks what a red color tells about a star's age. In 1911 many astronomers thought red stars were old and fading. Today we know color shows a star's surface heat: red stars are cooler and blue-white stars are hotter. Betelgeuse is a giant red star near the end of its life, but it is much younger than our Sun; big stars live fast. The fuzzy spot in the sword is the Orion Nebula, a great cloud of gas where new stars are being born.
The story
Orion was a great hunter in stories the ancient Greeks told. Read one version and have your child tell it back.
Nature notebook
Draw Orion: the four corner stars, the belt and the sword. Color Betelgeuse orange-red and Rigel blue-white, and label them.
Answers to the book's problems
Three stars in the belt; three in the sword (the middle one is the fuzzy nebula). Orion is south of the Pole-star, on the opposite side of the sky. Betelgeuse is orange-red; Rigel is blue-white. Betelgeuse rises first in the evening (it is the top of the figure).
Worked out for this site from the scan. If a number in your copy differs, trust the book.