Tukuk-OS✨ Boötes
Boo · herdsman · Northern sky
Boötes is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin, meaning herdsman; stars within it are named in the genitive form Boötis.
Facts about Boötes
| Constellation | Boötes |
|---|---|
| IAU abbreviation | Boo |
| Genitive (Latin) | Boötis |
| Meaning | herdsman |
| Brightest star | Arcturus (apparent magnitude -0.05) |
| Area | 907 square degrees |
| Hemisphere | Northern |
How big is Boötes on the sky?
With an area of 907 square degrees, Boötes is number 13 of 88 constellations by size — 2.2% of the whole celestial sphere. That is roughly 4,535 full moons of sky side by side (the Moon’s disc covers about 0.2 square degrees). The ranking runs from Hydra, the largest at 1,303°, down to Crux, the smallest at 68°; Boötes sits between neighbours Leo (947°) and Pisces (889°).
It is worth remembering what those borders are: since 1922 the IAU has drawn the 88 constellations as precise regions tiling the entire sky, so every star, every galaxy and every empty patch belongs to exactly one of them — ancient figures, modern surveying.
The name in use
Stars and variable objects inside Boötes are labelled with its genitive (possessive) form, Boötis: the Bayer designations run Alpha, Beta, Gamma… Boötis, and deep-sky objects are often called “of Boötis” in catalogues and papers. The Greek letters roughly follow brightness but do not always obey it — history, not rules, decided which star got Alpha. The Latin meaning of the name is herdsman; northern skies carry its brightest members, of which Arcturus shines at apparent magnitude -0.05.
Who can see it: a northern-sky constellation: from mid-northern latitudes it rides high, and from far south of the equator it never properly rises. From the equator, in the course of a year, well-nigh every constellation in the catalogue crosses the sky — the further you travel from it, the more of the opposite hemisphere you permanently leave behind.