1. 4 Types of Galaxies
4 TYPES OF GALAXIES

2. What is a galaxy?
A galaxy is a group of stars, gas, and dust held together by gravity.
All of the points of light seen in a galaxy are stars.

3. 4 Types of Galaxies
1. Spiral
2. Irregular
3. Elliptical
4. Lenticular

4. Spiral Galaxy
The most common type of galaxy is called a "spiral galaxy."
Not surprisingly, spiral galaxies look like spirals, with long arms winding toward a bright bulge at the center.
About 77% of the observed galaxies in the universe are spiral galaxies.
Our own galaxy, the Milky Way, is a typical spiral galaxy

8. Elliptical Galaxies
They are generally round but stretch longer along one axis than along the other.
Elliptical galaxies contain many older stars, up to one trillion, but little dust and other interstellar matter.
The universe's largest known galaxies are giant elliptical galaxies, which may be as much as two million light-years long.

12. Irregular Galaxies
Approximately 3% of galaxies observed cannot be classified as either ellipsoidal or spirals.
These galaxies have little symmetry in their structure and are termed irregular galaxies.

16. Lenticular Galaxy
Lenticular galaxies are disc galaxies (like spiral galaxies) which have used up or lost most of their interstellar matter and therefore have very little ongoing star formation.
As a result, they consist mainly of aging stars
Produce fewest stars.

19. CONSTELLATIONS

20. What are Constellations?
Constellations are named patterns of stars.
The classical -- "ancient" -- constellations that populate our sky began in the lands of the middle east thousands of years ago, their origins largely lost to time.
They passed through the hands of the ancient Greeks, who overlaid them with their legends and codified them in story and verse.
There are 88 named constellations

21. Orion

24. Big Dipper- Ursa Major

25. Little Dipper- Ursa Minor The most famous star in Ursa Minor is Polaris, the North Star
Polaris-North Star