Cooking Top Stars of The Saucepan
The most reliable of the Northern Hemisphere to see – the Plough is likely the first constellation you recognize when you first ‘Look up’.
The “Big Dipper” (a term mainly used in the United States and Canada; Plough and (historically) Charles’ Wain are used in the United Kingdom) is an asterism within Ursa Major composed of seven bright stars (six of them of the second magnitude or higher) that together comprise one of the best-known patterns in the sky.
Like many of its common names allude to, its shape is said to resemble either a ladle, an agricultural plough or wagon; in the context of Ursa Major, they are commonly drawn to represent the hindquarters and tail of the Great Bear. Starting with the “ladle” portion of the dipper and extending clockwise (eastward in the sky) through the handle, these stars are the following:
- α Ursae Majoris, known by the Arabic name Dubhe(“the bear”), which at a magnitude of 1.79 is the 35th-brightest star in the sky and the second-brightest of Ursa Major.
- β Ursae Majoris, called Merak (“the loins of the bear”), with a magnitude of 2.37.
- γ Ursae Majoris, known as either Phecdaor Phad (“thigh”), with a magnitude of 2.44.
- δ Ursae Majoris, or Megrez, meaning “root of the tail,” an appropriate name given its location as the intersection of the body and tail of the bear (or the ladle and handle of the dipper).
- ε Ursae Majoris, known as Alioth, a name which refers not to a bear but to a “black horse,” the name corrupted from the original and mis-assigned to the similarly named Alcor, the naked-eye binary companion of Mizar. Alioth is the brightest star of Ursa Major and the 33rd-brightest in the sky, with a magnitude of 1.76. It is also the brightest of the “peculiar A (Ap) stars,” magnetic stars whose chemical elements are either depleted or enhanced, and appear to change as the star rotates.
- ζ Ursae Majoris, Mizar, the second star in from the end of the handle of the Big Dipper, and the constellation’s fourth-brightest star. Mizar, which means “girdle,” forms a famous double star, with its optical companion Alcor(80 Ursae Majoris), the two of which were termed the “horse and rider” by the Arabs. The ability to resolve the two stars with the naked eye is often quoted as a test of eyesight, although even people with quite poor eyesight can see the two stars.
- η Ursae Majoris, known as either Alkaidor Benetnash, both meaning the “end of the tail.” With a magnitude of 1.85, Alkaid is the third-brightest star of Ursa Major.
Except for Dubhe and Alkaid, the stars of the Big Dipper all have proper motions heading toward a common point in Sagittarius. A few other such stars have been identified, and together they are called the Ursa Major Moving Group.
The stars Merak (β Ursae Majoris) and Dubhe (α Ursae Majoris) are known as the “pointer stars” because they are helpful for finding Polaris, also known as the North Star or Pole Star. By visually tracing a line from Merak through Dubhe and continuing, one’s eye will land on Polaris, accurately indicating true north.