When is the best time to observe Lambda Geminorum?

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

Where is Lambda Geminorum located in the sky?

Lambda Geminorum lies in the constellation Gemini at right ascension 07h 18m and declination +16° 32′.

What telescope do I need to split Lambda Geminorum?

Splitting Lambda Geminorum requires an aperture of roughly 80 mm or larger — the components are separated by about 9.7″ at magnitudes near 3.6. The companion is about 7.1 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Lambda Geminorum — Double Star in Gemini

Magnitude 3.6^m DoubleStar Gemini (Gem) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 3.58

Variable Type Delta Scuti (Pulsating)

Spectral Type A3V

Star Color White (B-V 0.11)

Distance 101 ly

2Position & Identifiers

RA 07h 18m 05.6s

Dec +16° 32' 25.0"

Constellation Gemini (Gem)

HR 2763

HIP 35350

HD 56537

SAO 96746

Bayer Lambda

Flamsteed 54 Gem

Double Cat 5961

SIMBAD

3How easy to split?

Primary 3.6 mag Companion 10.7 mag Separation 9.7″

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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 Triple

Components 3 (triple)

Component IDs O

Separation 9.7″

Companion Mag 10.7

Position Angle 36°

Star Colors A: White B: Yellow-white

Discoverer STF1061

Notes

ADS 5961A is dubious occultation double, 4.0, 5.0v, sep. 0.045". B, 10.7v at 10" is CPM.

Separation over time

Measured 1829 → 2021 (192 y)

Separation drift 9.6" → 9.7" (+0.10")

Rate +0.0005" / y

PA drift 31° → 36° (+5°, +0.026°/y)

Essentially fixed on human timescales — the same view your grandchildren will see.

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.