When is the best time to observe Zubenelhakrabi?

Zubenelhakrabi is best observed from April through June, with peak visibility during May when it transits around midnight in the Northern Hemisphere.

Where is Zubenelhakrabi located in the sky?

Zubenelhakrabi lies in the constellation Libra at right ascension 15h 36m and declination -14° 47′.

What telescope do I need to split Zubenelhakrabi?

Splitting Zubenelhakrabi requires an aperture of roughly 60 mm or larger — the components are separated by about 41.9″ at magnitudes near 3.9. The companion is about 7.3 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Zubenelhakrabi — Double Star in Libra

HIP 76333; Gamma Librae; 38 Librae

Magnitude 3.9^m DoubleStar Libra (Lib) Visible 2 Exoplanets

Star Map + List + Plan

About Zubenelhakrabi

Description

Zubenelhakrabi, Gamma Librae, is a G-type giant of spectral class G8.5 III about 163 light-years away in the constellation Libra. It shines at magnitude 3.91 and is a red-clump star actively fusing helium. Zubenelhakrabi has a mass of about 1.5 Suns and a radius of about 11 Suns.

Observing Tips

Zubenelhakrabi sits on the southern side of Libra, south of the main pan-and-scale pattern. In binoculars it appears as a warm yellow point. Best observed April through August.

History

The name Zubenelhakrabi comes from the Arabic "zubān al-'aqrab," meaning "the claw of the scorpion" — Libra's stars were originally part of Scorpius in Greek astronomy, representing the scorpion's claws, and only later reinterpreted as the scales of justice. The name preserves this ancient scorpion-claws identity. The IAU adopted the name in 2017.

Fun Facts

Libra is unique among the zodiac constellations in that it originally was not a separate figure — its stars were the claws of Scorpius in Babylonian and Greek tradition. The Romans separated them into a distinct "Scales" constellation around the 1st century BC. The surviving Arabic names (Zubenelgenubi, Zubeneschamali, Zubenelhakrabi) all still reference the scorpion claws.

Observe

1Physical Properties

Magnitude 3.91

Spectral Type G8.5III giant

Star Color Orange (B-V 1.01)

Distance 163 ly

2Position & Identifiers

RA 15h 35m 31.6s

Dec -14° 47' 22.0"

Constellation Libra (Lib)

HR 5787

HIP 76333

HD 138905

SAO 159370

Bayer Gamma

Flamsteed 38 Lib

Double Cat 9704

SIMBAD Wikipedia

3How easy to split?

Primary 3.9 mag Companion 11.2 mag Separation 41.9″

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard+	Hard	V. hard+
150 mm Newton 150mm Newt.	Medium+	Medium	Hard+
Celestron C8 (203 mm SCT) C8 203mm	Easy	Medium+	Medium

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Apr – Jun (peak: May)

5Multiple Star System Triple B: optical

Components 3 (triple)

Component IDs AP

Separation 41.9″

Companion Mag 11.2

Position Angle 158°

Star Colors A: Orange

Discoverer GOL 1

Notes

ADS 9704 AP, sep. 0.097", unresolved by speckle interferometry. Component B, 11.2v at 42", optical.

Separation over time

Measured 1878 → 2015 (137 y)

Separation drift 41.3" → 41.9" (+0.60")

Rate +0.0044" / y

PA drift 152° → 158° (+6°, +0.044°/y)

Slow change over generations — observable in lifetime comparisons.

Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.