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Kids: The study of the sky and celestial bodies
Some of the different kinds of celestial bodies are planets, moons, stars, comets, meteors, asteroids and galaxies. Our SUN is a star.
Some of the different kinds of star groups are constellations, open clusters, globular clusters, double stars, variable stars and nebula.
Our galaxy is called the MILKY WAY. There are billions of stars in the Milky Way. Sometimes when you look up at the night sky you can see the hazy light of millions of stars along the edge of the Milky Way. All the stars that we can see are within our galaxy. A very close neighbor galaxy that we can see without optical aid is the ANDROMEDA GALAXY. Andromeda is 2,300,000 (2.3 million) light years away. This is the furthest object that humans can see without the use of some type of optical aid. Only giant scientific telescopes allow seeing individual stars in neighboring galaxies. There are billions of other galaxies. The Hubble Space Telescope took a picture of the universe that shows 1,500 galaxies in a tiny patch of sky no bigger than a grain of sand held at arms length.
The brightest object in the sky after the sun and the moon is the planet VENUS. By May it will have moved to the morning sky, which is when we refer to Venus as the Morning Star. SATURN and JUPITER are next brightest after Venus. Jupiter appears bigger than any star. With binoculars you can see four of Jupiter’s moons. The moons move position every night. By May, Jupiter and Saturn will drop too low in the western sky to be seen, so enjoy them now. MARS rises late at night now but will be in the evening sky all summer. How can you tell planets from stars? Stars always appear in the same place; planets move throughout the year in relation to the stars.
Constellations are groups of stars that form pictures in the sky. Constellations are always visible at the same time of year. Even though all stars are moving through space, they are so far away that they seem to stay in the same place, so the pictures we see always stay the same. You don’t need any binoculars or telescope to see the constellations. Most are large pictures in the sky and are best seen without any optical aid.
The best way to learn your way around the sky is to pick a nice comfortable spot to put a blanket or pad on the ground, lie down on your back and look up. A reclining lawn chair works great. Standing up and bending your neck back to look up makes your neck sore and makes it difficult to hold binoculars steady. You can see much more if you can make the binoculars steadier. A tripod helps if you can attach your binoculars to it.
With binoculars you will be able to see craters on the moon, some double stars, star colors, a few globular clusters, many open clusters, some comets and a few galaxies. With a telescope you can see far more detail on the moon, Jupiter’s cloud bands, Saturn’s rings, many more star clusters, hundreds of double stars and dozens of galaxies and nebulae.
Use some of the maps of the stars and spend an evening to see how many of the named stars you can find. A planisphere is an inexpensive tool that will help you identify the stars and constellations overhead at anytime during the year. Get one about 9 to 10" large, smaller ones are hard to read. You will have a much greater appreciation of the nighttime sky when you can look up and know the names of the stars that you see.
BINOCULARS AND TELESCOPES ARE OPTICAL INSTRUMENTS THAT NEED TO BE HANDLED WITH CARE. DO NOT THROW OR DROP. ALWAYS WEAR THE NECK STRAP. WIPE OFF MOISTURE VERY GENTLY WITH SPECIAL CLOTH OR A COTTON BALL TO AVOID SCRATCHING LENSES. NEVER LOOK AT THE SUN WITH BINOCULARS OR A TELESCOPE.
Stars appear to travel across the sky each night because of the Earth’s rotation (spin) on its axis. But the North Star always seems to stay in the same place, half way up in the sky facing north. That’s because the Earth’s axis, or the North Pole, is tilted right at the North Star. Polaris is the North Star, the most important star in URSA MINOR. It is the end of the handle of the Little Dipper. How can you tell direction at night by finding the North Star? When you turn towards Polaris, you are facing directly north. The "pointers" of the Big Dipper always point right to it.
URSA MAJOR is the name of the Great Bear. A portion of this constellation is the Big Dipper. It looks like a soup ladle and the stars at the end of the cup are called the pointers. They always point directly at the North Star. The 2nd star in from the end of the handle is a famous double star. The bright one is Mizar, the horse, and the dim one is Alcor, the rider. Can you see them both? M81 and M82 are two bright galaxies close together near the head of the bear. They can be seen with binoculars.
CASSIOPEIA, the Queen’s Chair, has the shape of the letter W. It circles around the North Star the same as the Big Dipper but on the opposite side of the North Star from the Big Dipper. The bright star on the end of the W is Caph. Cassiopeia has many open clusters. Some can be seen with binoculars. The beautiful open cluster 457 is the Owl Cluster. It can be seen with a small telescope.
PEGASUS and ANDROMEDA are connected. Pegasus, the flying horse is seen as the great square. The upper left corner of the square is also the point of two long curved lines of stars that make up Andromeda, the hind legs of the horse. Use a chart to locate M31 in Andromeda and you will easily find it with binoculars. On the clearest nights you can see M31 with the naked eye.
M31, the Andromeda Galaxy, is the furthest object that humans can see without optical aid.
PERSEUS is a constellation with many interesting things to see. Use a chart book to locate the Double Cluster, labeled 884 & 869 on the chart. This double open cluster can be seen with the unaided eye as a fuzzy spot in the sky. Binoculars will show many stars and a telescope will show two dazzling groups of hundreds of stars each. The star Algol in Perseus is one of the most famous Variable stars. It changes brightness every three days.
ORIONthe Hunter follows TAURUS the Bull across the sky as they both follow the PLEIADES.
The PLEIADES, or the Seven Sisters, is an Open Cluster that looks like a tiny little dipper and is often mistaken for the little dipper. This group is a good test of eyesight. Some people can see only 6 stars here. The nine brightest stars in the group all have names. These nine stars represent the father, the mother and the seven sisters. Binoculars will show the beauty of this tiny little patch of stars. A small telescope shows about 100 stars. How many stars can you see here? On a very dark night I have seen 10. Keep trying! The longer you stay in the dark, the better your eyes become adapted to seeing faint light. After staying in the dark for one hour you will see twice as many stars.
The HYADES, the "V" shape, is the head of TAURUS the Bull. Aldeberan, a beautiful red star, is the brightest star in Taurus. The "V" is only a portion of the whole constellation, so it is called an asterism. The stars of open cluster the Hyades are 400 million years old.
ORION the Hunter is a big constellation and is easy to pick out. The name Orion is found in Egyptian literature from 3000 years ago. There are several bright stars in Orion that are very colorful. Betelgeuse at the upper left is orange and Rigel at the lower right is blue. Betelgeuse is 800 million miles in diameter, the largest of the red giant stars. It would fill our solar system almost out to Jupiter. The Orion Nebula, located in the sword stars that hang below Orion's belt, is one of the most interesting areas in the sky for telescope viewing. The stars here are very young, only 300,000 years old. Astronomers have discovered that what we see here is stars being formed.
Low and to the left after Orion comes the brightest star of all. Sirius, the 5th closest star to Earth, is in the constellation CANIS MAJOR, the Big Dog. High above it is Procyon, the bright star in CANIS MINOR, the Small Dog. The small dog keeps the big dog company as they follow right behind Orion. High to the left after Orion, we see GEMINI, the Twins. The main stars are the twins, Castor (green) and Pollux (yellow). Castor is a beautiful double star, but this double can only be seen in a telescope.
CANCER, the Crab, is faint and is hard to see, but with binoculars you can see the Open Cluster of stars in Cancer known as Praesepe, or "The Beehive". These stars are about 650 million years old.
Spring and Summer Constellations
LEO the Lion is easy to see. In April it is high overhead at 9:00 at night. The bright star Regulus is the lion’s heart. The bright star above Regulus, at the lion’s neck, is Algieba, a telescopic double star.
BOOTES, the herdsman, has the shape of a kite. The bright star at the bottom of the kite is named Arcturus, one of the brightest stars in the sky. Use Bootes to find the bright globular cluster M3.
HERCULES is next. Look for a keystone shape. This is the body of Hercules. Use a chart to locate the M13 globular cluster and look for it with binoculars. It is the brightest globular cluster in the northern sky. In binoculars it will look like a fuzzy round star. There are nearly a million stars in M13.
LYRA, the lyre has the shape of a parallelogram. The very bright star is Vega. Two interesting telescope objects are the Ring Nebula and Epsilon Lyra, the double double star.
CYGNUS, the swan, has the shape of a cross. The bright star at the tail of the swan is Deneb. The star at the head of the swan, or the bottom of the cross, is Albireo. High power binoculars will show Albireo is a beautiful colored double star. The Milky Way flows right through Cygnus.
AQUILA, the eagle, has the shape of a triangle. Its brightest star is Altair. Near the southern tip of the eagle is the open cluster M11 in SCUTUM. M11 has so many stars it appears to glow.
Deneb, Vega and Altair are three of the brightest stars in the sky and they form the Northern Triangle. The tip of the triangle always points south.
There are many other Open Clusters similar to The Pleiades. Nearly all of them require a telescope to be seen. A few can be seen with binoculars. Three of the most stunning Open Clusters that can be seen with binocular are M45, the Pleiades in Taurus, the Double Cluster in Perseus and M44, Praesepe (the Beehive) in Cancer. Some Open Clusters that you need a telescope to see are the Owl Cluster in Cassiopeia, the Christmas Tree Cluster in Monoceros, the Butterfly Cluster in Scorpius, M37 in Auriga and M35 in Gemini. A telescope shows that M35 has about 200 stars.
A Globular Cluster is such a very tightly packed group of stars that to us they appear as a hazy ball of light. Globular clusters have as many as several hundred thousand to a million stars, but a telescope can resolve only a few of the individual stars. My 5" telescope will resolve about 30 stars in M13. Globular Clusters are very old. The globular cluster M13 in the constellation Hercules is about 14 billion years old. It can be seen without optical aid on very dark, very clear nights. Globular Clusters are also very far away, near the outer edges of the Milky Way Galaxy. M13 is 22,000 light years away. M22 in Sagitarius can be spotted without optical aid.
A TIME LINE OF ASTRONOMY AND LIFE
Scientists who study the stars and celestial bodies are called Astronomers. Through Astronomy, they have discovered the oldest known objects in the universe are about 14 to 18 billion years old.
The stars of the globular cluster M13 in Hercules are about 14 billion years old.
The stars of the open cluster M67 in Cancer are about 10 billion years old.
4 ½ billion years ago our Solar System began.
Our Sun and planets began to form a distinct group held together by gravitational attraction.
4 billion years ago the first bacteria life forms began on Earth.
600 million light years away lies a group of galaxies we see in the constellation Hercules.
400 million years ago the stars of the Hyades, the "V" in Taurus, were formed.
240 million years ago dinosaurs began living on Earth.
70 million years ago dinosaurs became extinct, probably from a meteor impact.
When we look thru a telescope at M65 and M66, a pair of galaxies in the constellation LEO, the light we see is from 35 million years ago. These galaxies are 35 million light years away.
20 million years ago the stars of the Pleiades were formed. These are considered very young.
2.3 million years ago, the light we see now from the Andromeda Galaxy began its journey toward us. The Andromeda Galaxy is the furthest object that humans can see with the unaided eye. It is about 2.3 million light years away. It appears as a little hazy spot in the sky.
2 million years ago the first species of human life began on Earth.
300,000 years ago the Trapezium, the stars in the Orion Nebula were formed.
22,000 years ago, the light from M13 that we see now began its journey toward us.
4000 years ago, the ancient Babylonians and Macedoniansreferred to LEO as a lion.
Many of the Stars and Constellations got their names in ancient times.
About 400 years ago, around the year 1600, the telescope was invented.
In 1610, Galileo was the first to see Jupiter’s moons and Saturn’s rings.
In 1931, Edwin Hubble was the first using a telescope to see individual stars in the Andromeda Nebulae. This was the first time we understood this was a galaxy outside our own.
Our Sun is a star, the closest one to us. The next closest star to us is called Alpha Centauri. It is 4 1/3 light years away. The light from Alpha Centauri that we see now began its journey toward us about 4 years ago. It would take the fastest spaceships we have, traveling at 20,000 miles per hour, nearly 150,000 years to reach Alpha Centauri.
It takes 8 minutes for the Sun's light to reach us. The Sun is 93,000,000 (million) miles away.
It takes 2 seconds for the moon’s light to reach us. It varies from 223,000 to 252,000 miles away.
How far is a light year? It's the distance light travels in one year. Light travels at the speed of 186,000 miles per second. So one Light Year equals 186,000 miles per second x 60 seconds in one minute x 60 minutes in one hour x 24 hours in one day x 365 days in one year = 5,865,696,000,000 miles, almost 6 trillion miles in one year.