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.
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.
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.
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”.
Draco the dragon lies close to the North polar point of the celestial sphere. Thus, it is best viewed from north of the equator. This celestial dragon has a long serpentine shape that winds around the constellation Ursa Minor (better known by the name Little Dipper), which is far fainter than it’s companion, Ursa Major. The tail of Draco separates these two constellations.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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