When is the best time to observe Sigma Aurigae?

Sigma Aurigae is best observed from November through January, with peak visibility during December when it transits around midnight in the Northern Hemisphere.

Where is Sigma Aurigae located in the sky?

Sigma Aurigae lies in the constellation Auriga at right ascension 05h 25m and declination +37° 23′.

What telescope do I need to split Sigma Aurigae?

Splitting Sigma Aurigae requires an aperture of roughly 230 mm or larger — the components are separated by about 7.5″ at magnitudes near 5.0. The companion is about 7.0 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Sigma Aurigae — Double Star in Auriga

Magnitude 5.0^m DoubleStar Auriga (Aur) Visible

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1Physical Properties

Magnitude 4.99

Spectral Type K4III giant

Star Color Red (B-V 1.42)

Distance 1,087 ly

2Position & Identifiers

RA 05h 24m 39.2s

Dec +37° 23' 08.0"

Constellation Auriga (Aur)

HR 1773

HIP 25292

HD 35186

SAO 57981

Bayer Sigma

Flamsteed 21 Aur

Double Cat 3984

SIMBAD

3How easy to split?

Primary 5.0 mag Companion 12.0 mag Separation 7.5″

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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	Hard+	Hard+	Hard+

Easy Medium Hard Very hard Impossible

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

To reach "Medium" at Bortle 3, you'd need at least a 230 mm reflector.

4Visibility

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Best season Nov – Jan (peak: Dec)

5Multiple Star System Quadruple

Components 4 (quadruple)

Component IDs AB

Separation 7.5″

Companion Mag 12.0

Position Angle 163°

Star Colors A: Red

Discoverer BU 888

Notes

AB fixed.

Separation over time

Measured 1880 → 2022 (142 y)

Separation drift 7.9" → 7.5" (-0.40")

Rate -0.0028" / y

PA drift 171° → 163° (-8°, -0.056°/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.