When is the best time to observe Zeta Coronae Borealis?

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

Where is Zeta Coronae Borealis located in the sky?

Zeta Coronae Borealis lies in the constellation Corona Borealis at right ascension 15h 39m and declination +36° 38′.

What telescope do I need to split Zeta Coronae Borealis?

Splitting Zeta Coronae Borealis requires an aperture of roughly 80 mm or larger — the components are separated by about 6.3″ at magnitudes near 5.1. Larger apertures and steady seeing help resolve the pair cleanly.

Zeta Coronae Borealis — Double Star in Corona Borealis

HIP 76669; Zeta2 Coronae Borealis; 7 Coronae Borealis

Observable Double Star Excellent (66/100)

Sep: 6.3", Companion: mag 5.9

Magnitude 5.1^m DoubleStar Corona Borealis (CrB) Visible

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Observe

1Physical Properties

Magnitude 5.07

Spectral Type B7V

Star Color Blue-white (B-V -0.12)

Distance 217 ly

2Position & Identifiers

RA 15h 39m 22.7s

Dec +36° 38' 09.0"

Constellation Corona Borealis (CrB)

HR 5834

HIP 76669

HD 139892

SAO 64834

Bayer Zeta2

Flamsteed 7 CrB

Double Cat 9737

SIMBAD Wikipedia

3How easy to split?

Primary 5.1 mag Companion 5.9 mag Separation 6.3″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Easy
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 Apr – Jun (peak: May)

5Multiple Star System

Separation 6.3″

Companion Mag 5.9

Companion Sp B9V

Position Angle 306°

Star Colors A: Blue-white B: Blue-white

Discoverer STF1965

Notes

Binary with HR 5833.

Separation over time

Measured 1779 → 2024 (245 y)

Separation drift 5.5" → 6.3" (+0.80")

Rate +0.0033" / y

PA drift 296° → 306° (+10°, +0.041°/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.