When is the best time to observe 4 Centauri?

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

Where is 4 Centauri located in the sky?

4 Centauri lies in the constellation Centaurus at right ascension 13h 53m and declination -31° 56′.

What telescope do I need to split 4 Centauri?

Splitting 4 Centauri requires an aperture of roughly 60 mm or larger — the components are separated by about 14.8″ at magnitudes near 4.7. The companion is about 3.8 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

4 Centauri — Double Star in Centaurus

Observable Double Star Excellent (60/100)

Sep: 14.8", Companion: mag 8.5

Magnitude 4.7^m DoubleStar Centaurus (Cen) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.73

Spectral Type B4IV subgiant

Star Color Blue-white (B-V -0.14)

2Position & Identifiers

RA 13h 53m 12.5s

Dec -31° 55' 40.0"

Constellation Centaurus (Cen)

HR 5221

HIP 67786

HD 120955

SAO 204944

Flamsteed 4 Cen

SIMBAD

3How easy to split?

Primary 4.7 mag Companion 8.5 mag Separation 14.8″

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

Separation 14.8″

Companion Mag 8.5

Position Angle 185°

Star Colors A: Blue-white B: Yellow

Discoverer H N 51

Notes

Visual companion, 8.35V, +0.36(B-V), +0.12(U-B), A3Vm, vsini 71k/s.

Separation over time

Measured 1836 → 2016 (180 y)

Separation drift 18.0" → 14.8" (-3.20")

Rate -0.0178" / y

PA drift 184° → 185° (+1°, +0.006°/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.