When is the best time to observe Kappa Geminorum?

Kappa Geminorum is best observed from December through February, with peak visibility during January when it transits around midnight in the Northern Hemisphere.

Where is Kappa Geminorum located in the sky?

Kappa Geminorum lies in the constellation Gemini at right ascension 07h 44m and declination +24° 24′.

What telescope do I need to split Kappa Geminorum?

Splitting Kappa Geminorum requires an aperture of roughly 80 mm or larger — the components are separated by about 7.0″ at magnitudes near 3.6. The companion is about 6.4 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Kappa Geminorum — Double Star in Gemini

Magnitude 3.6^m DoubleStar Gemini (Gem) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 3.57

Spectral Type G9III giant

Star Color Orange (B-V 0.93)

Distance 141 ly

2Position & Identifiers

RA 07h 44m 26.8s

Dec +24° 23' 53.0"

Constellation Gemini (Gem)

HR 2985

HIP 37740

HD 62345

SAO 79653

Bayer Kappa

Flamsteed 77 Gem

Double Cat 6321

SIMBAD

3How easy to split?

Primary 3.6 mag Companion 10.0 mag Separation 7.0″

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

Easy Medium Hard Very hard Impossible

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

4Visibility

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Best season Dec – Feb (peak: Jan)

5Multiple Star System

Separation 7.0″

Companion Mag 10.0

Position Angle 243°

Star Colors A: Orange

Discoverer STT 179

Separation over time

Measured 1827 → 2021 (194 y)

Separation drift 5.0" → 7.0" (+2.00")

Rate +0.0103" / y

PA drift 240° → 243° (+3°, +0.015°/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.