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.
The Engagement Ring: Through binoculars, the North Star (Polaris) seems to be the brightest on a small ring of stars. Not a constellation or cluster, this asterism looks like a diamond engagement ring on which Polaris shines brightly as the diamond.
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.
Auriga is located north of the celestial equator. Its name is the Latin word for “charioteer”, associating it with various mythological charioteers, including Erichthonius and Myrtilus. Auriga is most prominent in the northern Hemisphere winter sky, along with the five other constellations that have stars in the Winter Hexagon asterism. Auriga is half the size of the largest constellation, Hydra. Its brightest star, Capella, is an unusual multiple star system among the brightest stars in the night sky. Because of its position near the winter Milky Way, Auriga has many bright open clusters within its borders, including M36, M37, and M38. In addition, it has one prominent nebula, the Flaming Star Nebula, associated with the variable star AE Aurigae.
Boötes has a funny name. Pronounced boh-OH-deez, this constellation’s name means sheepherder, or herdsman. It looks kind of like a kite, or a shoe. Some remember that “Boötes look like a boot” to help pick it out in the sky.
Cancer is one of the zodiac constellations, which means the ecliptic—or plane of the Solar System, runs through it. The Sun, Moon, and planets move along the ecliptic, and therefore, you can sometimes find these Solar System objects in Cancer. Cancer is a medium-sized medium-brightness constellation, located between Gemini and Leo along the ecliptic. You can find the notable open star cluster Beehive cluster (also known as M44 or Praesepe) within Cancer. In greek mythology, cancer was a crab that, under the instruction of Hera, latched onto Hercules’s feet while he was battling Hydra. Hercules and Hydra are also constellations, and Hydra borders Cancer.
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”.
The name Coma Berenices means “Berenice’s Hair”. This is the only modern constellation named for a person who really lived, as opposed to a purely mythological character. Queen Berenices II of Egypt lived 2260 years ago, and as legend has it, she sacrificed her hair to the goddess Aphrodite, in exchange that her husband should return safely from war. When the hair went missing form the temple, it was said that it had been carried to the heavens, where it forevermore resides.
Corvus is Latin for crow, or raven. This constellation is associated with nearby constellations Hydra the water snake, and Crater the cup. There are no particularly bright stars in Corvus. The four main stars make a polygon shape.
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.
Libra is a fainter constellation, but easy enough to spot, once you’re familiar with the shape. It lies along the ecliptic (the plane of the Solar System), so planets pass through now and then. The names of the two brightest stars of Libra, which are Zubeneschamali and Zubenelgenubi, come form Arabic, and mean “the northern claw”, and “the southern claw”, respectively. Libra was once considered to be part of the constellation Scorpius, the scorpion. Zubeneschamali and Zubenelgenubi were seen as the claws of the scorpion.
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.
Virgo’s brightest star Spica is found by following the curve of the handle of the Big Dipper (“arc to Arcturus, in Boötes, then spike to Spica”).The rest of the constellation isn’t particularly bright, but Virgo lies along the ecliptic—the plane of the Solar System, so bright planets pass through occasionally.
M51 Whirlpool Galaxy
M51, the Whirlpool Galaxy, gets its name from its bright and prominent spiral arms. It lies at a distance of 23 million light-years away. It also has a smaller, companion galaxy (NGC 5195). The two galaxies are one of the best examples of interacting galaxies.
M82 Cigar Galaxy
M82, the “Cigar Galaxy” is an edge-on spiral galaxy, 12 million light-years away, and perhaps 37,000 light-years across. There are vast gas clouds in this galaxy, where stars are being born at an incredible rate.
M3 is a globular cluster with a half of a million stars. It orbits the core of our Milky Way Galaxy almost perpendicular to the galactic disk. It is currently 33,900 light-years away, and approaching our Solar System at 100 miles per second.
Omega (ω) Centauri
Omega Centauri is one of the biggest and closest globular star clusters, seen very low to the south from Kitt Peak, and best seen from Southern latitudes. This ball of ten million stars is 16,000 light-years away. It is one of the largest globular clusters in the galaxy, spanning a diameter of 150 light-years, and may actually be the rememnant of a dwarf galaxy.
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.
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 Green Flash
What we call “The Green Flash” is not so much a flash as a flicker of green color, seen on the top of the sun as it sets (or rises). This rare event needs just the right atmospheric conditions.
Zodiacal light is the faint, smooth glow marking the ecliptic (the plane of the solar system). It is sunlight scattered off of gas and dust that orbits the Sun. This is a rare sight, only visible under very dark skies, and best viewed early in the year when the Ecliptic is higher above the horizon.
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.
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.
NGC 3242 (Ghost of Jupiter)
Jupiter is the largest planet in the Solar System, a “gas giant” 11 Earth-diameters across. Its atmosphere contains the Great Red Spot, a long-lived storm 2-3 times the size of the Earth. The 4 large Galilean satellites and at least 63 smaller moons orbit Jupiter.
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.
Iota (ι) Cancri
Iota (ι) Cancri is a binary star in the constellation Cancer, the crab. The brighter star is a pale yellow giant, and the fainter star is smaller and bluish-white. This pair is about 300 light-years away and the stars are almost 3000 astronomical units apart.
Mizar & Alcor
In the handle of the Big Dipper, Mizar & Alcor (ζ & 80 Ursae Majoris) or the “Horse & Rider” form a naked-eye double star. They are traveling through space together about 80 light-years away from us, separated by about a light-year. However, it is unknown if they are actually gravitationally bound to each other. A telescope splits Mizar itself into two stars, but these both are again doubles, bringing the total in this system to six.
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