Getting Started

Professional astronomers come in two varieties: observational and theoretical.

Professional observational astronomers mostly use expensive scientific instruments to look through their massive telescopes for them. They spend a lot of time measuring things, taking data, and crunching the numbers. They are very good at designing and performing experiments that answer the big questions to which no one knows the answers.

Professional theoretical astronomers think up new ideas and new models for fitting the data so that it makes sense in the field of physics. They are great at asking the big questions in the first place. Albert Einstein was a theoretical astronomer, as he hated to do experiments of any kind. Instead, he preferred to sit back and think about what might happen in the laboratory of his mind.

And then there's the rest of us... like you and me. We're amateur astronomers. Amateur astronomers usually have smaller telescopes, typically 4” to 20” in diameter. They generally don’t get paid to do astronomy. They just do it for the love of it, and they are the ones you’ll find on sidewalks and sharing views of the sky with the general public during local stargazing events. Many amateur astronomers have discovered new objects based on their raw knowledge of the sky.

Are you ready to dive into the exciting world of astronomy? Let's go!

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Star Wobble
How do astronomers find planets around distant stars? If you look at a star through binoculars or a telescope, you’ll quickly notice how bright the star is, and how difficult it is to see anything other than the star, especially a small planet that doesn’t generate any light of its own! Astronomers look for a …
Design a Solar System
What would happen if our solar system had three suns?  Or the Earth had two moons? You can find out all these and more with this lesson on orbital mechanics. Instead of waiting until you hit college, we thought we'd throw some university-level physics at you... without the hard math.
Build a REAL Scale Model of the Solar System
Ever wonder exactly how far away the planets really are?  Here’s the reason they usually don’t how the planets and their orbits to scale – they would need a sheet of paper nearly a mile long! To really get the hang of how big and far away celestial objects really are, find a long stretch …
Telling Time by the Stars
The stars rise and set just like our sun, and for people in the northern hemisphere, the Big Dipper circles the north star Polaris once every 24 hours. Would you like to learn how to tell time by the stars?
Seasons
One common misconception is that the seasons are caused by how close the Earth is to the Sun. Today you get to do an experiment that shows how seasons are affected by axis tilt, not by distance from the Sun. And you also find out which planet doesn’t have sunlight for 42 years. The seasons …
Black Hole Bucket
What comes to mind when you think about empty space? (You should be thinking: “Nothing!”) One of Einstein’s greatest ideas was that empty space is not actually nothing – it has energy and can be influenced by objects in it. It’s like the T-shirt you’re wearing. You can stretch and twist the fabric around, just …
Advanced Telescope Building
So you've played with lenses, mirrors, and built an optical bench. Want to make a real telescope? In this experiment, you'll build a Newtonian and a refractor telescope using your optical bench.Materials:optical benchindex card or white walltwo double-convex lensesconcave mirrorpopsicle stickmirrorpaper clipflash lightblack garbage bagscissors or razorrubber bandwax paperhot glue
Light, Lasers, and Optics
When I was in grad school, I needed to use an optical bench to see invisible things. I was trying to ‘see’ the exhaust from a  new kind of F15 engine, because the aircraft acting the way it shouldn’t – when the pilot turned the controls 20o left, the plane only went 10o. My team …
Fire & Optics
Today you get to concentrate light, specifically the heat, from the Sun into a very small area. Normally, the sunlight would have filled up the entire area of the lens, but you’re shrinking this down to the size of the dot. Magnifying lenses, telescopes, and microscopes use this idea to make objects appear different sizes …
Cosmic Ray Detector
When high energy radiation strikes the Earth from space, it’s called cosmic rays. To be accurate, a cosmic ray is not like a ray of sunshine, but rather is a super-fast particle slinging through space. Think of throwing a grain of sand at a 100 mph… and that’s what we call a ‘cosmic ray’.
Solar Rotation
You are going to start observing the Sun and tracking sunspots across the Sun using one of two different kinds of viewers so you can figure out how fast the Sun rotates. Sunspots are dark, cool areas with highly active magnetic fields on the Sun’s surface that last from hours to months. They are dark …
Phases of the Moon
The Moon appears to change in the sky. One moment it’s a big white circle, and next week it’s shaped like a sideways bike helmet. There’s even a day where it disappears altogether. So what gives? The Sun illuminates half of the Moon all the time. Imagine shining a flashlight on a beach ball. The …
Eclipses and Transits
It just so happens that the Sun’s diameter is about 400 times larger than the Moon, but the Moon is 400 times closer than the Sun. This makes the Sun and Moon appear to be about the same size in the sky as viewed from Earth. This is also why the eclipse thing is such …
Moons of Jupiter
On a clear night when Jupiter is up, you’ll be able to view the four moons of Jupiter (Europa, Ganymede, Io, and Callisto) and the largest moon of Saturn (Titan) with only a pair of binoculars. The question is: Which moon is which? This lab will let you in on the secret to figuring it …
Jupiter’s Jolts
Jupiter not only has the biggest lightning bolts we’ve ever detected, it also shocks its moons with a charge of 3 million amps every time they pass through certain hotspots. Some of these bolts are cause by the friction of fast-moving clouds. Today you get to make your own sparks and simulate Jupiter’s turbulent storms. …
What’s Up in the Sky?
Today you get to learn how to read an astronomical chart to find out when the Sun sets, when twilight ends, which planets are visible, when the next full moon occurs, and much more. This is an excellent way to impress your friends. The patterns of stars and planets stay the same, although they appear …
Meteorites
A meteoroid is a small rock that zooms around outer space. When the meteoroid zips into the Earth’s atmosphere, it’s now called a meteor or “shooting star”. If the rock doesn’t vaporize en route, it’s called a meteorite as soon as it whacks into the ground.
Retrograde Motion
If you watch the moon, you'd notice that it rises in the east and sets in the west. This direction is called 'prograde motion'. The stars, sun, and moon all follow the same prograde motion, meaning that they all move across the sky in the same direction.
Kepler’s Swinging System
Kepler’s Laws of planetary orbits explain why the planets move at the speeds they do. You’ll be making a scale model of the solar system and tracking orbital speeds. Kepler’s 1st Law states that planetary orbits about the Sun are not circles, but rather ellipses. The Sun lies at one of the foci of the …