When is the best time to observe Iota Librae?

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

Where is Iota Librae located in the sky?

Iota Librae lies in the constellation Libra at right ascension 15h 12m and declination -19° 48′.

What telescope do I need to split Iota Librae?

Splitting Iota Librae requires an aperture of roughly 60 mm or larger — the components are separated by about 57.7″ at magnitudes near 4.5. The companion is about 6.3 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Iota Librae — Double Star in Libra

HIP 74392; Iota1 Librae; 24 Librae

Magnitude 4.5^m DoubleStar Libra (Lib) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.54

Range 4.53 - 4.56

Period 3.1 days

Variable Type Alpha2 CVn (Magnetic Rotating)

Spectral Type A0pSi

Star Color Blue-white (B-V -0.08)

Distance 109 ly

2Position & Identifiers

RA 15h 12m 13.3s

Dec -19° 47' 30.0"

Constellation Libra (Lib)

HR 5652

HIP 74392

HD 134759

SAO 159090

Bayer Iota1

Flamsteed 24 Lib

Double Cat 9532

SIMBAD Wikipedia

3How easy to split?

Primary 4.5 mag Companion 10.9 mag Separation 57.7″

Sign in and configure your equipment and default location to see a personalized row.

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard+	Hard+	Hard
150 mm Newton 150mm Newt.	Medium+	Medium+	Medium
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

Set a location in User Settings to see visibility data.

Best season Apr – Jun (peak: May)

5Light Curve

6Multiple Star System Quadruple

Components 4 (quadruple)

Component IDs AP

Separation 57.7″

Companion Mag 10.9

Position Angle 111°

Star Colors A: Blue-white

Discoverer H 6 44

Notes

AP 5.1 B9IV, 5.6 B9V, 23.42y, a = 0.116", combined light, colors. Mean mass 5 solar. BC, 10.5, 11.2v sep. 1.9". A | physical pair in orbital motion about AP at 58"; possibly quintuple system.

Separation over time

Measured 1781 → 2016 (235 y)

Separation drift 65.2" → 57.7" (-7.50")

Rate -0.0319" / y

PA drift 113° → 111° (-2°, -0.009°/y)

Apparent motion is significant on a human timescale — worth revisiting in a decade.

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.