Thuban

HR 5291 · HIP 68756 · α Dra

👁️ Naked-eye

📋 A written introduction is coming — for now this page shows official values only.

Star

Apparent magnitude: 3.68 mag
Parallax: 10.76 mas → about 303.1 light-years away
Spectral type: A0III SB
Right ascension: 211.0973°
Declination: 64.3759°
Designation: HR 5291
Bayer designation: α Dra
HIP number: 68756
IAU name adopted: 2016-06-30
Name language: Arabic
Name origin (IAU): The formation of this name begins with the name for the Arabic Almagest period for γ Dra: ra's al-tinnin, "the Serpent's Head." In medieval times this was transliterated into Latin as raztaben, rahtaben, razcaben, and several other corruptions (eventually leading to the name for β Dra). By Early Modern times the form Rastaben had appeared, and this name was erroneously attributed, in its last part, to the Arabic word thu'ban, "serpent", rather than to al-tinnin (subsequently thu<ban was wrongly regarded as a name for the Arabic Almagest period for the constellation Draco). Finally in recent times, the erroneous word, written as "Thuban," was applied as a star name to α Dra.

Constellation

Light from this object takes about 303 years to reach Earth — the light you see tonight left around AD 1723 (official distance ÷ speed of light).
At magnitude 3.7 it is bright enough for the naked eye (limit about 6) — look from somewhere dark.
Declination 64.4° — from Seoul (37.6° N) it never sets and circles the northern sky all night.

Worked out from this object's official values.

HR 5291 · HIP 68756 · α Dra

👁️ Naked-eye

📋 A written introduction is coming — for now this page shows official values only.

Apparent magnitude: 3.68 mag
Parallax: 10.76 mas → about 303.1 light-years away
Spectral type: A0III SB
Right ascension: 211.0973°
Declination: 64.3759°
Designation: HR 5291
Bayer designation: α Dra
HIP number: 68756
IAU name adopted: 2016-06-30
Name language: Arabic
Name origin (IAU): The formation of this name begins with the name for the Arabic Almagest period for γ Dra: ra's al-tinnin, "the Serpent's Head." In medieval times this was transliterated into Latin as raztaben, rahtaben, razcaben, and several other corruptions (eventually leading to the name for β Dra). By Early Modern times the form Rastaben had appeared, and this name was erroneously attributed, in its last part, to the Arabic word thu'ban, "serpent", rather than to al-tinnin (subsequently thu<ban was wrongly regarded as a name for the Arabic Almagest period for the constellation Draco). Finally in recent times, the erroneous word, written as "Thuban," was applied as a star name to α Dra.

Constellation

Light from this object takes about 303 years to reach Earth — the light you see tonight left around AD 1723 (official distance ÷ speed of light).
At magnitude 3.7 it is bright enough for the naked eye (limit about 6) — look from somewhere dark.
Declination 64.4° — from Seoul (37.6° N) it never sets and circles the northern sky all night.

Worked out from this object's official values.