Astronomy is the study of anything outside Earth's atmosphere. It began as people observing the sky to track the seasons. Today, astronomers use various tools like telescopes, satellites, and probes. There are about 15,000 professional astronomers worldwide and 300,000 amateur astronomers in the US. Amateur astronomers make observations and discoveries. Astronomy includes areas like observational astronomy using different wavelengths of light, celestial mechanics of planetary motion, and theoretical astronomy of developing models.

1. What is Astronomy?

2. What is Astronomy
Astronomy is the study of anything outside the
Earth’s atmosphere.

3. How do astronomer study the sky?
• Binoculars
• Telescopes
• NASA Probes
• Radio
• Satellites

4. How many Astronomers are there?
• Professional Astronomers
- 15,000 Worldwide
• Amateur Astronomers
- 300,000 in United States Alone

5. How did Astronomy start?
At first it was just a man looking at the sky to
track the sun. He wanted to know when the
seasons would start and end to let him know
when to plant and harvest.

6. What does an Amateur Astronomer do?
• Study sky through observation
• Memorize Constellations
• Watch for changes
• Spot asteroids and comets

7. Asteroid Circling the Earth

8. Is it worth it for the Amateur
Astronomer?
Yes!!!
Astronomy is one field where amateur have, and
still do, make significant contributions.
Many Professionals, with all the technology
available today, hardly even look at the sky.

9. What are the areas of study in
Astronomy?
• Observational Astronomy
• Celestial Mechanics
• Theoretical Astronomy
• Subfields

10. I Zwicky 18 Galaxy – Credit: NASA

11. Observational Astronomy
• Optical Astronomy – Can be done by
amateurs. Just looking at the sky.
• Ultraviolet Astronomy – Looking at sky in the
ultraviolet wavelengths
• X –Ray Astronomy – Looking at sky be
observing x-rays.
• Gamma Astronomy – Uses satellites to
observe the gamma rays strike the
atomosphere.

12. Celestial Mechanics
This involves working out the paths of the
planets and moons to know how everything
will travel, and to know where it will be in the
future.
To send a probe to another planet, we need to
know where it will be in the future.

13. Theoretical Astronomy
This involves figuring out theories to fit the data
that the astronomer has.
As more data is received, if it does not fit in the
present model, the model must be adjusted.

14. Some Subfields
• Study of the Sun
• Study of Solar Systems
• Study of Galaxies
• Study of Black Holes
Almost every part of the skies had a group
studying it, and trying to figure out how it
works.

15. An Observation of the Sun

16. What is Astronomy?
When you look up at the sky and wonder, you
are on the first steps to practicing astronomy
and becoming an astronomer.

17. More Resources
What is Astronomy?