Kitt Peak Nightly Observing Program
Splendors of the Universe on YOUR Night!
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The Big Dipper (also known as the Plough) is an asterism consisting of the seven brightest stars of the constellation Ursa Major. Four define a “bowl” or “body” and three define a “handle” or “head”. It is recognized as a distinct grouping in many cultures. The North Star (Polaris), the current northern pole star and the tip of the handle of the Little Dipper, can be located by extending an imaginary line from Big Dipper star Merak (β) through Dubhe (α). This makes it useful in celestial navigation.
Constellation Ursa Minor is colloquially known in the US as the Little Dipper, because its seven brightest stars seem to form the shape of a dipper (ladle or scoop). The star at the end of the dipper handle is Polaris, the North Star. Polaris can also be found by following a line through two stars in Ursa Major—Alpha and Beta Ursae Majoris—that form the end of the ‘bowl’ of the Big Dipper, for 30 degrees (three upright fists at arms’ length) across the night sky.
Andromeda was the princess of myth who was sacrificed by her parents to the sea monster Cetus. Fortunately, the hero Perseus came along to save her, and they were eventually married. The constellation Andromeda is host to the Andromeda Galaxy. Although there are smaller, dwarf galaxies that are closer to our galaxy, Andromeda is the closest big galaxy like our own; in fact, it’s bigger.
Canis Major, the “big dog”, boasts the brightest star in the night sky—Sirius! Also known as The Dog Star because of the constellation it resides in, Sirius is a massive, hot, blue star—and it’s right next door! One of the reasons Sirius is so bright is that it is so close to us—only 8.6 light-years away. It’s name comes from Greek, and means “glowing” or “scorcher”.
Cassiopeia is widely recognized by its characteristic W shape, though it may look like an M, a 3, or a Σ depending on its orientation in the sky, and your position on Earth. However it’s oriented, once you’ve come to know its distinctive zig-zag pattern, you’ll spot it with ease. The plane of the Milky Way runs right through Cassiopeia, so it’s full of deep sky objects—in particular, a lot of open star clusters. Cassiopeia is named for the queen form Greek mythology who angered the sea god Poseidon when she boasted that her daughter Andromeda was more beautiful than his sea nymphs.
King Cepheus from Greek mythology was husband to Cassiopeia and father of Andromeda. The brightest stars in the constellation Cepheus seem to form a kind of crooked house, with the roof pointing to the North. this constellation is very near the Celestial North Pole, so it’s not visible from the Southern Hemisphere. The star Delta Cephei was the first ever identified cepheid variable star, a very important kind of variable stars that helps astronomers determine distances to nearby galaxies.
Cygnus is a large constellation, prominent in the Northern Hemisphere. Its name comes from the Greek for “Swan” and can be imagined as a giant, celestial swan, flying overhead, with its wings fully extended. The brightest star in Cygnus is Deneb, which is one of the brightest stars in the sky, and a whopping 800 lightyears away! Deneb is one point of an asterism called the Summer Triangle—three very bright stars that form a large triangle shape prominent in the Northern hemisphere summer skies.
Orion is a famous constellation, well known especially for the Belt of Orion—three stars in a line at what seems to be the waist of a human figure. The bright stars Rigel and Betelgeuse are two of the brightest stars in the sky. Between the Belt and Rigel you can see the Orion Nebula—the closest star forming region to our Solar System. A beautiful object in a telescope or binoculars, you can also just make out the nebula naked-eye.
This constellation is named for one of the most beloved creatures of Greek mythology—the winged horse named Pegasus. Within Pegasus is a well known asterism containing the 3 brightest stars in the constellation (+ 1 in Andromeda) called The Great Square of Pegasus. Alpheratz, the brightest star in the square, actually belongs to the constellation Andromeda, but in the past, this star had been considered to belong to both constellations.
You can look to Taurus, the bull, to find the two closest open star clusters to our Solar System. The Pleiades (or, Seven Sisters) is the second closest at 444 light-years away. It’s an obvious cluster to even the naked eye. The Pleiades is named for the seven daughters of Atlas and Pleione of Greek Mythology. To the left of the pleiades, the Hyades (siblings to the Pleiades in mythology) is the closest open star cluster to Earth at 153 light-years away. The Hyades has a characteristic V shape to help identify it.
Ursa Major, or, the Big Bear, is one of the best known and most well recognized constellations, but you might know it by a different name. Contained within the boundaries of the constellation Ursa Major is the Big Dipper, which is not a true constellation, but an asterism. The Big Dipper is useful for finding both the North Star and the bright star Arcturus. Follow the curve of the handle to “arc to Arcturus” and use to two stars in the dipper opposite the handle to point to the North Star.
Ursa Minor, the Little Bear, is much fainter than it’s companion the Big Bear, Ursa Major. Within Ursa Minor is the well known asterism The Little Dipper. The end of the tail of the bear, or the end of the handle of the dipper, is a star called Polaris—the Pole Star, or the North Star. This special star happens to sit at the point where the Earth’s axis of rotation intersects the sky
M42 The Orion Nebula
M42, the Orion Nebula is a region of star formation about 1,300 light-years away—the closest to our Solar System. It is roughly 30 light-years across, and contains enough material to make 2,000 stars the size of our sun.
M31 Andromeda Galaxy
The Andromeda Galaxy is our nearest major galactic neighbor. It is a spiral galaxy 2,500,000 light-years away, and has a diameter of 220,000 light-years. This galaxy contains as much material as 1.5 trillion suns.
Quick streaks of light in the sky called meteors, shooting stars, or falling stars are not stars at all: they are small bits of rock or iron that heat up, glow, and vaporize upon entering the Earth’s atmosphere. When the Earth encounters a clump of many of these particles, we see a meteor shower lasting hours or days.
That clumpy band of light is evidence that we live in a disk-shaped galaxy. Its pale glow is light from about 200 billion suns!
Human technology! There are almost 500 of these in Low Earth Orbit (we can’t see the higher ones). We see these little “moving stars” because they reflect sunlight.
The “Double Cluster” (NGC 884 and NGC 869) is a pair of two open star clusters that are a treat for binoculars and telescopes alike. Each is a congregation of many hundreds of stars, around 50-60 light-years in diameter. These clusters are both about 7,500 light-years away.
The Hyades is the nearest open star cluster to the Solar System at about 150 light-years away and thus, one of the best-studied of all star clusters. It consists of hundreds of stars sharing the same age, place of origin, chemical content, and motion through space. In the constellation Taurus, its brightest stars form a V shape along with the brighter red giant Aldebaran, which is not part of the cluster, but merely lying along our line of sight. The age of the Hyades is estimated to be about 625 million years. The cluster core, where stars are most densely packed, has a diameter of about 18 light-years.
M36 Pinwheel Cluster
M36, the “Pinwheel Cluster” is one of three bright open star clusters in the constellation of Auriga. It lies about 4,100 light-years away, and is about 14 light-years across, contains about 60 stars, and is about 25 million years old.
M37 Salt & Pepper Cluster
M37, the “Salt and Pepper Cluster” is one of three bright open star clusters in the constellation Auriga. It is the brightest and richest of the three. It lies about 4,500 light-years away, contains about 150 stars, has a diameter of about 25 light-years, and is 450 million years old.
M38 Starfish Cluster
M38, the “Starfish Cluster” is one of a trio of bright open star clusters in the constellation Auriga. It lies about 4,200 light-years away, has a diameter of about 25 light-years, and is 220 million years old.
M45 The Pleiades
M45, the “Pleiades,” is a bright, nearby star cluster, in the last stages of star formation. About seven stars stand out as the brightest in the cluster, and is why the cluster is also known as the “Seven Sisters,” alluding to the Pleiades, or Seven Sisters from Greek mythology. In Japanese, the cluster is known as “スバル,” “Subaru,” and is featured as the logo of the automobile manufacturer of the same name. The Pleiades lies about 440 light-years away and is a very young (for an open star cluster) 100 million years old.
The same side of the Moon always faces Earth because the lunar periods of rotation and revolution are the same. The surface of the moon is covered with impact craters and lava-filled basins. The Moon is about a fourth of Earth’s diameter and is about 30 Earth-diameters away.
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