When is the best time to observe Lambda Octantis?

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

Where is Lambda Octantis located in the sky?

Lambda Octantis lies in the constellation Octans at right ascension 21h 51m and declination -82° 43′.

What telescope do I need to split Lambda Octantis?

Splitting Lambda Octantis requires an aperture of roughly 100 mm or larger — the components are separated by about 3.3″ at magnitudes near 5.3. Larger apertures and steady seeing help resolve the pair cleanly.

Lambda Octantis — Double Star in Octans

Observable Double Star Good (59/100)

Sep: 3.3", Companion: mag 7.3

Magnitude 5.3^m DoubleStar Octans (Oct) Visible

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Observe

1Physical Properties

Magnitude 5.29

Spectral Type G8-K0III

Star Color Orange (B-V 0.75)

Distance 297 ly

2Position & Identifiers

RA 21h 50m 54.3s

Dec -82° 43' 09.0"

Constellation Octans (Oct)

HR 8280

HIP 107843

HD 206240

SAO 258914

Bayer Lambda

SIMBAD

3How easy to split?

Primary 5.3 mag Companion 7.3 mag Separation 3.3″

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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 Jul – Sep (peak: Aug)

5Multiple Star System

Separation 3.3″

Companion Mag 7.3

Position Angle 62°

Star Colors A: Orange B: Red

Discoverer HJ 5278

Notes

Binary. Companion A3.

Separation over time

Measured 1835 → 2015 (180 y)

Separation drift 3.4" → 3.3" (-0.10")

Rate -0.0006" / y

PA drift 83° → 62° (-21°, -0.117°/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.