Rasalas
HR 3905 · HIP 48455 · μ Leo
👁️ Naked-eye
📋 A written introduction is coming — for now this page shows official values only.
Star
- Apparent magnitude
- 3.88 mag
- Parallax
- 26.28 mas → about 124.1 light-years away
- Spectral type
- K0III
- Right ascension
- 148.1909°
- Declination
- 26.007°
- Designation
- HR 3905
- Bayer designation
- μ Leo
- HIP number
- 48455
- IAU name adopted
- 2016-09-12
- Name language
- Arabic
- Name origin (IAU)
- Applied in recent times from an abbreviation of its name for the Arabic Almagest period ra's alasad (al-shamali), "(the Northern [Part] of) the Lion's Head." As originally applied, μ Leo was "Rasalasad Borealis" abbreviated in the first Western astronomical source as "Rasalas. Bor.," for lack of space in the line), and ε Leo was "Rasalasad Australis" (after the Arabic).
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 124 years to reach Earth — the light you see tonight left around AD 1902 (official distance ÷ speed of light).
- At magnitude 3.9 it is bright enough for the naked eye (limit about 6) — look from somewhere dark.
- Declination 26° — 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.