When is the best time to observe 18 Librae?

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

Where is 18 Librae located in the sky?

18 Librae lies in the constellation Libra at right ascension 14h 59m and declination -11° 09′.

What telescope do I need to split 18 Librae?

Splitting 18 Librae requires an aperture of roughly 60 mm or larger — the components are separated by about 19.9″ at magnitudes near 5.9. The companion is about 4.0 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

18 Librae — Double Star in Libra

Magnitude 5.9^m DoubleStar Libra (Lib) Visible

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Observe

1Physical Properties

Magnitude 5.87

Spectral Type K3-IIICN1

Star Color Orange (B-V 1.26) (reddened by dust)

2Position & Identifiers

RA 14h 58m 53.6s

Dec -11° 08' 39.0"

Constellation Libra (Lib)

HR 5582

HIP 73310

HD 132345

SAO 158946

Flamsteed 18 Lib

Double Cat 9456

SIMBAD

3How easy to split?

Primary 5.9 mag Companion 9.8 mag Separation 19.9″

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

Easy Medium Hard Very hard Impossible

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

4Visibility

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Best season Mar – May (peak: Apr)

5Multiple Star System Triple C: optical

Components 3 (triple)

Component IDs AB

Separation 19.9″

Companion Mag 9.8

Companion Sp G8V

Position Angle 38°

Star Colors A: Orange (reddened by dust) B: Orange

Discoverer STF1894

Notes

AB CPM. B is G8V.

Separation over time

Measured 1782 → 2022 (240 y)

Separation drift 18.0" → 19.9" (+1.90")

Rate +0.0079" / y

PA drift 45° → 38° (-7°, -0.029°/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.