Introduction to Constellations Backyard Astronomy

The Night Sky People have watched the night skies for millions of years. Some just out of curiosity. Some out of boredom. Some looking for portents, either good or bad. However, the one thing that they all saw was that there was a pattern in the way the stars revolved around the heavens.

The Night Sky You need only to look up for a few hours to begin to see these same patterns yourself. Like the Sun, stars rise in the east and set later in the west.

What is a star? A STAR is a large sphere of glowing gases. Stars change over time. Which is the closest star to Earth? THE SUN! The sun is a medium sized star MUCH, MUCH larger than Earth

Star Finders When you first see the sun in the morning, your spot on the earth as just started to face the sun. As the day goes by, the spinning earth turns past the sun. It’s highest at noon.

Star Finders Your last view of the sun comes at sunset. The earth is turning you away from the sun. At night, stars rise and set the same way the sun does in the daytime because the earth is turning past them too.

Patterns of Stars People of ancient time saw the constellations as character or animals in the sky. They made up stories to explain how the object, animal, or character came into the night sky. A pattern or group of stars in the sky is called a constellation.

Star Patterns

The Big Dipper and Other Constellations The stars in the sky appear to be moving. If you look for constellations, you will find that they are in different positions at different times in the night. If you look closely, you will notice that the stars appear to move around a central star. We call this star the North Star or Polaris. However, it is not the stars that are moving. We are!!! The earth is rotating. Therefore, the stars in the sky look like they are moving to us.

Finding Polaris and Why Polaris (or the North Star) is where you want to start. Because Polaris is aligned with the Earth’s axis of rotation, it remains fixed, with all the other planets and stars appearing to move around it. It is the one star that remains fixed at all times.

Why Can We Always See the North Star? The North Star is located almost directly above the North Pole. The earth’s axis points towards it.

Stars as Tools for Navigation The North Star is called Polaris and located directly above the North Pole. This star appears in the same place every night all year long. In the Northern Hemisphere, if you find Polaris you will be able to tell which direction is north. The Southern Hemisphere does not have a star to help you find its pole. In stead it has what is known as a Southern Cross. The Southern Cross consists of 4 bright stars and some dimmer ones. All of these together point to the south pole.

Why Do We See Different Constellations in the Sky? As the earth moves in its orbit around the sun, the stars which we see are different. Constellations we see change with the seasons Also, as the earth rotates on its axis, the stars which we see are different. The sky at 7pm looks different than the sky at 10pm. Finally, people look at the sky from different locations on the earth see different stars.

One Way to Find Polaris Find the Big Dipper: The two stars that form the front of the cup of the dipper define a line pointing to Polaris.

The Big Dipper

The Great Bear

Movement of the Big Dipper over the Course of a year

The Stars Circling Polaris

Lets try a demonstration to show the movement. 1. I need a volunteer to be earth 2. Everyone else is going to be a star! We need a circle with all the stars on the outside and the earth in the middle.

Brainpops Constellations Telescopes Constellation Songs: https://www.youtube.com/watch?v=GzaMw oo9Ue0

How to find Constellations

Now That You’re Oriented, It’s Time to Explore. You’re pointed in the right direction, but what now. Stars and constellations move constantly and seasonally. What am I looking for? What you need is a star map.

STAR CHARTS How can we identify constellations in the night sky? The use of a star chart can help us! A STAR CHART is a map of the stars in the night sky.

STAR CHARTS On a star chart, lines often connect the stars that might make up a constellation. Different star charts must be used at different times of the year and in different places on Earth. Many stars visible from the Southern hemisphere cannot be seen from the Northern hemisphere.

STAR CHARTS

Lets Make One. http://www. skyandtelescope

Specific stars are visible depending upon: · from where on the planet Earth you view the sky. · the position of the Earth in its yearly journey around the Sun. · stars on the opposite side of the Sun are not visible from the Earth.

What other tools can help us identify constellations? STAR CHARTS are the BEST for identifying a constellation in the sky. A COMPASS is the BEST for locating DIRECTION (North, South, East, and West) You need to know direction before you can use a star chart correctly.

What other invention helps us view items in space? A telescope!

NOTES: Star- large __________ of glowing _________ Constellations- a _________ or group of ______ in the sky Star Chart- _______ of the ______ in the night sky used as a way to identify constellations Compass- used to locate _________ in order to use a star chart _________ Telescope- used to see ______ away ________ in ________ up-close

NOTES: Star- large sphere of glowing gases Constellations- a pattern or group of stars in the sky Star Chart- map of the stars in the night sky used as a way to identify constellations Compass- used to locate direction in order to use a star chart correctly Telescope- used to see far away objects in space up-close

Other Cool Things

As seen from the Earth, the sun appears projected against the fixed background stars. As the Earth revolves around the Sun during the year, the sun will appear to move through the stars, making one complete circuit of the sky in 365 days. The stars through which the sun moves are located along the Ecliptic and comprise the 12 constellations of the Zodiac. The sun spends about one month in each sign of the zodiac.

The stars opposite the sun make up our night sky The stars opposite the sun make up our night sky. Because of the Earth’s revolution around the sun, the night sky constantly changes as well. With each season having its distinctive grouping of constellations. The stars that are in the daytime sky or winter, for example, will be the nighttime stars of summer.

A Few Constellations...

Circumpolar Constellations - Ursa Major – The Big Bear - This is the constellation that houses the ever famous Big Dipper!  - Ursa Minor – The Little Bear - Cassiopeia – The Queen of Ethiopia - Cepheus – The King of Ethiopia - Draco – The Dragon

Ursa Minor Once you’ve located Polaris, you’re ready to identify your first constellation. Polaris is the last star located in the handle of the asterism, the Little Dipper. The name of the constellation that contains the Little Dipper is Ursa Minor or Little Bear.

Ursa Minor Ursa Minor, also called the Little Dipper, is a circumpolar constellation. This means it never sets in the northern sky. The true figure represented by the stars is the Little Bear. There are several mythological stories behind these famous constellations. In Greek myth, Zeus was having an affair with the lovely Callisto. When his wife, Hera, found out she changed Callisto into a bear. Zeus put the bear in the sky along with the Little Bear, which is Callisto's son, Arcas.

Ursa Minor

Ursa Major Ursa Major is probably the most famous constellation, with the exception of Orion. Also known as the Great Bear, it has a companion called Ursa Minor, or Little Bear. Everyone living in the Northern Hemisphere has probably spotted the easily recognized portion of this huge constellation. The body and tail of the bear make up what is known as the Big Dipper. Several different cultures saw a big bear in the sky. The ancient Greeks had a few different stories to explain how the animal ended up there. In one story, Hera discovered Zeus was having an affair with Callisto and turned her into a bear. Zeus put her in the sky along with her son, Arcas, who became the Little Bear.

Ursa Major

Draco Draco the dragon, is only present in the Northern Hemisphere, so those living in the Southern Hemisphere will never see this long constellation. The easiest way to spot Draco is by finding his head. It consists of four stars in a trapezoid, burning brightly just north of Hercules. From there, the tail slithers through the sky, eventually ending between the Big and Little Dippers. It can be difficult to trace Draco in the night sky. From the head, follow the body north towards Cepheus. It suddenly shifts south and west, ending up between the two dippers. The end of the constellation is held by Thuban, which was the pole star over 4,000 years ago.

Draco

Orion’s Belt 46

The constellation Orion is in the south The constellation Orion is in the south. Look for the three bright stars in a row that make up Orion’s belt.