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If you haven't already, please start by reading Lesson 1: The North Star and Lesson 2: The Circumpolar Constellations before proceeding.
So, now you're familiar with the North Star, and all of its circumpolar friends. Other constellations are far enough away from Polaris to rise and set the same way the sun does. Star charts are arranged with times of night, hour by hour, and months of the year. That's all well and good for advanced stargazers, but that's a level of complexity unnecessary for the beginner. Let's simplify:
You're most likely to be stargazing from sometime between when it gets dark enough to see all the stars until, let's say... 11:30 p.m., right? I call that "prime star-watching time."
Because of the position of Earth as it orbits the sun every 365 days, different constellations will be overhead during prime star-watching time depending on the season. Constellations visible on a summer night will be "up" during the daytime in the winter, so you won't be able to see them.
The Summer Triangle is a great example of an asterism you can see during the summer. I call those "summer constellations." We'll get to some of those later. For now, we're going to focus on one of my favorite fall/winter constellations, Orion. He'll be most visible during prime star-watching time from Octoberish through Februaryish.
How to find Orion? Find that Big Dipper again. Now turn around, approximately 180°. You should be facing the correct general region of sky.
Here's my friend Orion, with just his stars. A well-known asterism (remember, that's a recognizable group of stars that aren't technically a constellation by themselves) in Orion is his belt.
Those three diagonal close-together stars make up the belt, and those stars are the easiest way to find Orion in the sky.
Orion has several interesting features. Notice that blue star down in the corner? That's actually a blue star. Blue stars are younger, smaller, and hotter than your average yellow star. This one is called Rigel (RYE-jell).
Rigel is around 800 light years away, which means when you see that blue star, you're seeing the light that left Rigel 800 years ago. That sounds pretty far away, but in the grand scheme of the Universe, Rigel is pretty close to Earth.
Up and to the left (the shoulder opposite Rigel), there's a red star (not RED-red, just kind of pinkish-orange). Red stars are older, larger, and cooler than yellow stars. That one is called Betelgeuse (BAY-tell-jooz, or, as almost everyone says, beetle-juice).
Betelgeuse is a red supergiant. It is almost 2000 times the radius of our sun, and could fit within it over 2,000,000,000,000,000 Earths. Betelgeuse is expected to become a supernova sometime in the next million years or so. Because of its distance from Earth, it's possible that it has already done so, but the light from such an event would take hundreds of years to reach us.
The dagger hanging from Orion's belt contains a nebula. The middle "star" you see is a nebula made up of dust and gasses, which will eventually condense enough to form new stars. A birthplace for stars is visible from Earth with the naked eye!
Here is an actual photograph of Orion hanging out on the Oregon Coast.
Can you find his belt? It's nearly horizontal in this shot.
Now find Rigel (only very slightly blue in this photo), and Betelgeuse (definitely pinkish-orange) and the dagger hanging from the belt.
Orion is a hunter. He holds his shield in the arm shown on the right hand side of the diagram above, and a club or sword in the arm with Betelgeuse as the shoulder.
Orion hunts with his two dogs; we'll meet them in the next lesson, but they are visible in this photograph. After you become familiar with how to find them, come back to this lesson and check the photograph again.