Algol
HR 936 · HIP 14576 · β Per
👁️ Naked-eye
📋 A written introduction is coming — for now this page shows official values only.
Star
- Apparent magnitude
- 2.12 mag
- Parallax
- 36.27 mas → about 89.9 light-years away
- Spectral type
- B8V
- Right ascension
- 47.0422°
- Declination
- 40.9556°
- Designation
- HR 936
- Bayer designation
- β Per
- HIP number
- 14576
- IAU name adopted
- 2016-06-30
- Name language
- Arabic
- Name origin (IAU)
- Applied in medieval times from an abbreviation of its name for the Arabic Almagest period ras al-ghul "the Demon's Head" (for Ptolemy's Gorgon-head). "Algol" is one of the oldest Arabic star names applied in the West, from the end of the 10th century A.D.
Source:IAU Working Group on Star Names · checked 2026-11-02 ↗ESA Hipparcos Catalogue (ESA Gaia Archive) · checked 2026-11-03 ↗
Related
Constellation
In everyday life
- Light from this object takes about 90 years to reach Earth — the light you see tonight left around AD 1936 (official distance ÷ speed of light).
- At magnitude 2.1 it is bright enough for the naked eye (limit about 6) — look from somewhere dark.
- Declination 41° — it rises above the horizon in Seoul (37.6° N), so it is visible from Korea in the right season.
Worked out from this object's official values.