When is the best time to observe Nu Ceti?

Nu Ceti is best observed from September through November, with peak visibility during October when it transits around midnight in the Northern Hemisphere.

Where is Nu Ceti located in the sky?

Nu Ceti lies in the constellation Cetus at right ascension 02h 36m and declination +05° 36′.

What telescope do I need to split Nu Ceti?

Splitting Nu Ceti requires an aperture of roughly 80 mm or larger — the components are separated by about 8.1″ at magnitudes near 4.9. The companion is about 4.2 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Nu Ceti — Double Star in Cetus

Magnitude 4.9^m DoubleStar Cetus (Cet) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.86

Spectral Type G8III giant

Star Color Orange (B-V 0.87)

Distance 1,631 ly

2Position & Identifiers

RA 02h 35m 52.5s

Dec +05° 35' 36.0"

Constellation Cetus (Cet)

HR 754

HIP 12093

HD 16161

SAO 110635

Bayer Nu

Flamsteed 78 Cet

Double Cat 1971

SIMBAD

3How easy to split?

Primary 4.9 mag Companion 9.1 mag Separation 8.1″

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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	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 Sep – Nov (peak: Oct)

5Multiple Star System

Separation 8.1″

Companion Mag 9.1

Position Angle 80°

Star Colors A: Orange

Discoverer STF 281

Notes

Binary. Companion 9.08V, +0.56(B-V), +0.19(U-B), F7V.

Separation over time

Measured 1827 → 2016 (189 y)

Separation drift 5.5" → 8.1" (+2.60")

Rate +0.0138" / y

PA drift 87° → 80° (-7°, -0.037°/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.