When is the best time to observe Lambda Arietis?

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

Where is Lambda Arietis located in the sky?

Lambda Arietis lies in the constellation Aries at right ascension 01h 58m and declination +23° 36′.

What telescope do I need to split Lambda Arietis?

Splitting Lambda Arietis requires an aperture of roughly 60 mm or larger — the components are separated by about 37.3″ at magnitudes near 4.8. Larger apertures and steady seeing help resolve the pair cleanly.

Lambda Arietis — Double Star in Aries

Observable Double Star Excellent (62/100)

Sep: 37.3", Companion: mag 6.7

Magnitude 7.3–740.0^m DoubleStar Aries (Ari) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.79

Spectral Type F0V

Star Color Yellow-white (B-V 0.28)

Distance 116 ly

2Position & Identifiers

RA 01h 57m 55.7s

Dec +23° 35' 46.0"

Constellation Aries (Ari)

HR 569

HIP 9153

HD 11973

SAO 75051

Bayer Lambda

Flamsteed 9 Ari

Double Cat 1563

SIMBAD

3How easy to split?

Primary 4.8 mag Companion 6.7 mag Separation 37.3″

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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 Sep – Nov (peak: Oct)

5Multiple Star System Quadruple C,D: optical

Components 4 (quadruple)

Component IDs AB

Separation 37.3″

Companion Mag 6.7

Companion Sp F7V

Position Angle 48°

Star Colors A: Yellow-white B: Yellow

Discoverer H 5 12

Notes

ADS 1563B, 7.40V, +0.58(B-V), +0.07(U-B), dG1, CPM; vsini =<25k/s.

Separation over time

Measured 1777 → 2020 (243 y)

Separation drift 38.0" → 37.3" (-0.70")

Rate -0.0029" / y

PA drift 48° → 48° (+0°, +0.000°/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.