Kitt Peak Nightly Observing Program
Splendors of the Universe on YOUR Night!
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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.
The Winter Hexagon or Winter Circle/Oval is an asterism appearing to be in the form of a hexagon with vertices at Rigel, Aldebaran, Capella, Pollux, Procyon, and Sirius. It is mostly upon the Northern Hemisphere’s celestial sphere!
Smaller and more regularly shaped is the Winter Triangle (also known as the Great Southern Triangle), an approximately equilateral triangle that shares two vertices (Sirius and Procyon) with the larger asterism. The third vertex is Betelgeuse, which lies near the center of the hexagon. These three stars are three of the ten brightest objects, as viewed from Earth, outside the Solar System. Betelgeuse is also particularly easy to locate, being a shoulder of Orion, which assists stargazers in finding the triangle.
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”.
This little constellation with a name that means “little dog” has only 2 bright stars. One of them is Procyon—one of the brightest stars in the sky, and at only 11.5 light-years away, it’s one of our nearest neighbors in the galactic neighborhood. The name Procyon comes from Greek, and means “before the dog”, referring to the star Sirius, also known as The Dog Star in neighboring Canis Major, the “big dog”.
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.
Gemini is a well known zodiac constellation. Zodiac constellations line up with the plane of the Solar System in our sky, an intersection known as the ecliptic. This means you will find planets passing through Gemini from time to time. Gemini is also grazed by the plane of the Milky Way, and therefore has a few deep sky objects within its boundaries. Gemini’s brightest stars get their names from twins Castor and Pollux of Greek mythology.
Hydra, the sea serpent, with it’s long, serpentine shape, is the largest constellation by area, in the sky. Hydra is sandwiched between the plane of the Solar System (the ecliptic) to the north, and the plane of the Milky Way galaxy to the south. Just out of reach of the galactic plane, there aren’t any particularly bright stars in Hydra, but there is a variety of deep sky objects, including a few galaxies. Nearby are constellations crater, a cup, and corvus, a crow, closely related to hydra in Greek myth.
Leo is a fairly well known constellation, because the plane of the Solar System runs through it. Such constellations are called Zodiac Constellations. Leo has some notable, bright stars, in it to boot. The brightest of these, Regulus is at the bottom of a series of stars arrayed in the form of a sickle, or a backwards question mark. This constellation does look more or less like the side profile of a lion lying on the ground, with its head up.
Lepus is a smaller, medium brightness constellation. It can be found immediately to the south of the constellation Orion, at the feet of the hunter. The best known star of Lepus, is not one that is visible to the naked-eye. R Leporis, also known as Hind’s Crimson Star, is a ruby red carbon star. Just take a look with a telescope and see how strikingly red it is compared to other stars. An abundance of carbon in the star’s atmosphere filters out certain wavelengths of light, giving the star its extra red appearance.
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.
Hero of Greek mythology, Perseus is the character who slayed Medusa and rescued the Princess Andromeda from the sea monster Cetus. This is why you will find the constellations Andromeda, Cetus, and Andromeda’s parents Cassiopeia and Cepheus, nearby each other in the sky. Perseus’s brightest star is called Mirfak (Arabic for elbow). The plane of the Milky Way runs through Perseus, so there are many deep sky objects to be found.
Pisces, the fish, is a faint, roughly V shaped constellation. It has been depicted as two fish tied to the ends of a rope (or cord) which is bent into a V shape. None of the stars in Pisces are particularly bright, or well known, but occasionally, bright planets pass through Pisces as they follow the path of the ecliptic (the plane of the Solar System) across the sky. This is why Pisces is well known despite being faint—it’s a zodiac constellation.
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.
The ecliptic is a path in the sky, forming a great circle around the Earth, which the Sun and other planets of the Solar System move along. It is formed where the plane of the Solar System intersects with the Earth’s sky.
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 twinkling of star light is a beautiful effect of the Earth’s atmosphere. As light passes through our atmosphere, its path is deviated (refracted) multiple times before reaching the ground. Stars that are near to the horizon will scintillate much more than stars high overhead since you are looking through more air (often the refracted light will display individual colors). In space, stars would not twinkle at all. Astronomers would like it if they could control the effects of this troubling twinkle.
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.
M35 is an open star cluster of over 300 stars. It lies at a distance of 2,800 light-years from Earth, near the foot of Castor, one of the Gemini twins. Tiny nearby cluster NGC 2158 is in the same field of view.
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.
M44 The Beehive
M44, the “Beehive Cluster,” and also known as “Praesepe,” is a large, bright, diffuse open star cluster containing about 400 stars. It lies fairly close, at a distance of under 600 light-years.
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.
NGC 7662 Blue Snowball
NGC 7662: A planetary nebula nicknamed the “Blue Snowball.” It is a round cloud thrown off by a dying star, expanded to 1.6 lightyears in diameter. The expanding hot gas would have fried any planets orbiting the star.
51 Pegasi is a Sun-like star located about 50 lightyears from Earth. The 51 Pegasi system is home to the first exoplanet to ever be discovered, known as 51 Pegasi b or Dimidium. 51 Peg b is a large planet, about half the mass of Jupiter, orbiting very close to its parent star. The star 51 Pegasi can actually be seen with the naked eye under fairly dark skies.
Betelgeuse (α Orionis)
Betelgeuse (also called Alpha Orionis, α Orionis, or α Ori) is one of the brightest and largest known stars, though it is not one of the most massive. Located approximately 600 light-years from Earth, it is part of the constellation Orion and a vertex of the Winter Triangle asterism. Its large volume suggests that if it were at the center of the Solar System, it would wholly engulf Mercury, Venus, Earth, and Mars, with its surface extending out to between the orbits of Mars and Jupiter. It is classified as a red supergiant and as a semiregular variable star—that is, it shows considerable periodicity as its light changes, but this periodicity is sometimes irregular.
Castor (α Gem)
Castor (α Geminorum) is a multiple star in the constellation Gemini, the twins. Through the telescope, a close pair of bright white stars and a more distant red dwarf companion are visible, but these are each spectroscopic binaries, making Castor a six-star system. Castor is about 50 light-years away. The bright components orbit each other with a period of about 450 years.
Double Double (ε Lyr)
The Double-Double (ε Lyrae) looks like two stars in binoculars, but a good telescope shows that both of these two are themselves binaries. However, there may be as many as ten stars in this system! The distant pairs are about 0.16 light-year apart and take about half a million years to orbit one another. The Double-Double is about 160 light-years from Earth.
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