Dubb, more generally Dubhe, the Bear, is the abbreviation of the Arabians' Ṭhahr al Dubb al Akbar, the "Back of the Greater Bear", Dubb being first found in the Alfonsine Tables.
Al Bīrūnī said that it was the Hindu Kratu, the Rishi or Sage.
Lockyer asserts that it was Āk, the Eye, i.e. the prominent one of the constellation, utilized in the alignment of the walls of the temple of Hathor at Denderah, and the orientation point of that structure perhaps before 5000 B.C.; at all events, before the Thigh became circumpolar, about 4000 B.C. This was in the times of the Hor-she-shu, the worshipers of Horus, before the reign of Mena, ( Mena, Menes, or Min was the first historic king of Egypt, his date being variously given from 5867 B.C. to 3892 B.C., Flinders Petrie making it, from astronomical data, 4777 B.C. ) when the star had a declination of over 64°, — now about 62°24ʹ. And he finds two other temples also so oriented.
As typifying a goddess of Egypt, it was Bast Isis and Taurt Isis.
The Chinese know it as Tien Choo, Heaven's Pivot, and as Kow Ching.
α is 5° from β and 10° from δ, and, being always visible, these stars afford a ready means of accurate eye measurement of others adjacent. p438The Keepers was Arago's name for them; while, as the Pointers, they indicate to beginners in astronomy the pole-star, 28 3/4° distant from α, and Regulus, 45° away towards the south; and they have been called the Two Stars.
They are circumpolar north of about 32°45ʹ; and, with Polaris, received much attention in the first almanac ( This is said to have been the second of such works; the first being variously given as published in Vienna by Purbach, or in Buda, or in Poland a few years previously. ) that was printed in London, in 1473.
Klein surmised, in 1867, that Dubhe shows remarkable, although irregular, variations in color, — not in light, — from red to yellow, in a period of 54 1/2 days; but this is still in doubt. Its spectrum is Solar, and it is approaching our system at the rate of twelve miles a second.
The 11th‑magnitude companion, .97 of a second away, was discovered by Burnham in 1889, and is thought to be in rapid revolution around it.
Merak, or Mirak, is from Al Marāḳḳ, the Loin (of the Bear); but Chilmead said Miraë, and Scaliger, Mizar. It may have been known by the Greeks as Helike, one of their names for the whole.
The Chinese called it Tien Seuen, an Armillary Sphere, and the Hindus, Pulaha, one of the Rishis.
Its spectrum is Sirian, and it is moving toward us about 18 1/2 miles a second.
Close of it, on the west, lies the Owl Nebula, NGC 3587, 97 M., discovered by Mechain in 1781, and so called from the two interior circular spaces, each with a central star representing the eye; although one of these stars seems to have disappeared since 1850. the angular diameter of this nebula — 2ʹ40ʺ — indicates a magnitude sufficient to contain thousands of solar systems.
Phacd and Phachd, Phad, Phaed, Phecda, Phekda, and Phegda, are all from Al Faḣdh, the Thigh, where this star is located in the figure.
Al Bīrūnī said that it was Pulastya, one of the Hindu Seven Sages.
The Chinese knew it as Ke Seuen Ke, and as Tien Ke, another Armillary Sphere.
Its spectrum is similar to that of β, and the star is approaching us at the rate of 16.6 miles a second. It is 8° distant from β, and 4 1/2° from δ.
δ, 3.6, pale yellow.
Megrez is from Al Meghrez, the Root of the Tail.
In China it was Kwan, and Tien Kuen, Heavenly Authority.
With the Hindus it may have been Atri, one of their Seven Rishis, and the Vishṇu-Dharma said that it ruled the other stars of the Bear.
It is 10° distant from α; 4 1/2° from γ; 5 1/2° from ε; and 32° from the pole, directly opposite β Cassiopeiae, and almost on the equinoctial colure. α, β, γ, and δ form the bowl of the Dipper, the body of the Bear, and the frames of the Bier, Plough, and Wain, but occupy a space of less than 1/4 of the whole constellation. Within this square Heis shows eight stars.
Megrez is thought to be slightly variable, and to have decreased in lustre during the present century, on the very doubtful ground that it is much fainter than the succeeding ε. As to this Miss Clerke writes:
The immemorially observed constituents of the Plough preserve no fixed order of relative brilliancy, now one, now another of the septett having at sundry epochs assume the primacy.
But this is uncertain, although we know that Ptolemy rated it at the 3d magnitude and Tycho at the 2d.
Alioth, sometimes Allioth, seems to have originated in the first edition of the Alfonsine Tables, and appeared with Chaucer in the Hous of Fame as Aliot; with Bayer, as Aliath, from Scaliger, and as Risalioth; with Riccioli, as Alabieth, Alaioth, Alhiath, and Alhaiath, all somewhat improbably derived, Scaliger said, from Alyat, ( The syllable Al, in this word Alyat, is not the Arabic definite article) the Fat Tail of the Eastern sheep. But the later Alfonsine editions adopted Aliare and Aliore — Riccioli's Alcore — from the Latin Almagest of 1515, on Al Tizini's statement that the word was Al Ḥawar, the White of the Eye, or the White Poplar Tree, i.e. Intensely Bright; Hyde transcribing the original as Al Haur. Ulug Beg had Al Haun, but Ideler rejecting this as not being an Arabic word, substituted Al Jaun, the Black Courser, as if belonging to the governor, Al Ḳāʼid, the star η, and its comparative faintness gives some probability to this conjecture. Assemani, however, said that on the Cufic globe it is "Alhut," the Fish, — one of the many instances of blundering that Ideler attributed to him.
Bayer also assigned to it the Micar, Mirach, and Mizar that we give to p440η, and designated it as Λαγών, the Flank, and Ὑπόζωμα, the Diaphragm, as marking those parts of the Bear's figure.
Al Bīrūnī said that it was Añgiras among the Hindu Seven Sages.
In China it was Yuh Kang, the Gemmeous Transverse, a portion of an early astronomical instrument; while other stars between it and δ were Seang, the Minister of State.
ε has a Sirian spectrum, and is in approach toward us at the rate of 19 miles a second. It is 5 1/2° from δ, and 4 1/2° from ζ.
In 1838 Sir John Herschel thought it the lucida of the seven stars, but in 1847 that η had taken its place. Franks, in 1878, considered ε the lucida, and that the sequence was ε, η, ζ, α, β, γ, and δ.