Rasalgethi
* alf Her · HIP 84345 · α1 Her
👁️ Naked-eye
📋 A written introduction is coming — for now this page shows official values only.
Star
- Apparent magnitude
- 2.78 mag
- Parallax
- 9.07 mas → about 359.6 light-years away
- Spectral type
- M5IIvar
- Right ascension
- 258.6619°
- Declination
- 14.3903°
- Designation
- * alf Her
- Bayer designation
- α1 Her
- HIP number
- 84345
- IAU name adopted
- 2016-06-30
- Name language
- Arabic
- Name origin (IAU)
- Applied with various spellings since medieval times, from its name for the Arabic Almagest period ra's al-jathi, "the Kneeler's Head."
Source:ESA Hipparcos Catalogue (ESA Gaia Archive) · checked 2026-11-03 ↗IAU Working Group on Star Names · checked 2026-11-02 ↗
Related
Constellation
In everyday life
- Light from this object takes about 360 years to reach Earth — the light you see tonight left around AD 1666 (official distance ÷ speed of light).
- At magnitude 2.8 it is bright enough for the naked eye (limit about 6) — look from somewhere dark.
- Declination 14.4° — 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.