When is the best time to observe Lambda Tucanae?

Lambda Tucanae is best observed from August through October, with peak visibility during September when it transits around midnight in the Northern Hemisphere.

Where is Lambda Tucanae located in the sky?

Lambda Tucanae lies in the constellation Tucana at right ascension 00h 52m and declination -69° 30′.

What telescope do I need to split Lambda Tucanae?

Splitting Lambda Tucanae requires an aperture of roughly 60 mm or larger — the components are separated by about 20.5″ at magnitudes near 6.2. Larger apertures and steady seeing help resolve the pair cleanly.

Lambda Tucanae — Double Star in Tucana

HIP 4084; Lambda1 Tucanae

Magnitude 6.2^m DoubleStar Tucana (Tuc) Visible

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Observe

1Physical Properties

Magnitude 6.22

Spectral Type F7IV-V subgiant

Star Color Yellow (B-V 0.56)

2Position & Identifiers

RA 00h 52m 24.3s

Dec -69° 30' 16.0"

Constellation Tucana (Tuc)

HR 252

HIP 4084

HD 5190

SAO 248269

Bayer Lambda1

SIMBAD Wikipedia

3How easy to split?

Primary 6.2 mag Companion 7.4 mag Separation 20.5″

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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 Aug – Oct (peak: Sep)

5Multiple Star System

Separation 20.5″

Companion Mag 7.3

Position Angle 83°

Star Colors A: Yellow B: Yellow

Discoverer DUN 2

Separation over time

Measured 1834 → 2021 (187 y)

Separation drift 22.5" → 20.5" (-2.00")

Rate -0.0107" / y

PA drift 77° → 83° (+6°, +0.032°/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.