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.
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!
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.
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.
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.
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.
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
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.
Kitt Peak has an abundance of clear nights, but that doesn’t mean the clouds never move in. We hope you’ll join us again another time when our dark mountain skies are at their best!
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.
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.
M41 is an open star cluster located just below the brightest star in the night sky, Sirius. It contains about 150 stars spread out over 25 light-years, and is 2,300 light-years away.
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.
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.
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.
Rigel (β Ori)
Rigel (β Orionis) is the brightest star in the constellation Orion, and the seventh brightest star in the night sky, with a visual magnitude of 0.13. Rigel is a triple star system. The primary star (Rigel A) is a blue-white supergiant around 120,000 times as luminous as the Sun. It has exhausted its core hydrogen and swollen out to 79 times the Sun’s radius. An Alpha Cygni variable, it pulsates periodically. Visible in small telescopes and 500 times fainter than Rigel A, Rigel B is itself a spectroscopic binary system, consisting of two main sequence blue-white stars of spectral type B9V that are themselves estimated to be 2.5 and 1.9 times as massive as the Sun.
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