When is the best time to observe Mu Canis Majoris?

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

Where is Mu Canis Majoris located in the sky?

Mu Canis Majoris lies in the constellation Canis Major at right ascension 06h 56m and declination -14° 03′.

What telescope do I need to split Mu Canis Majoris?

Splitting Mu Canis Majoris requires an aperture of roughly 100 mm or larger — the components are separated by about 2.8″ at magnitudes near 5.0. Larger apertures and steady seeing help resolve the pair cleanly.

Mu Canis Majoris — Double Star in Canis Major

Observable Double Star Excellent (63/100)

Sep: 2.8", Companion: mag 7.1

Magnitude 5.0^m DoubleStar Canis Major (CMa) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 5.00

Spectral Type G5III+A2 giant

Star Color Red (B-V 1.18)

2Position & Identifiers

RA 06h 56m 06.6s

Dec -14° 02' 37.0"

Constellation Canis Major (CMa)

HR 2593

HIP 33345

HD 51250

SAO 152123

Bayer Mu

Flamsteed 18 CMa

Double Cat 5605

SIMBAD

3How easy to split?

Primary 5.0 mag Companion 7.1 mag Separation 2.8″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard+	Hard+	Hard+
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 Nov – Jan (peak: Dec)

5Multiple Star System Quadruple D: optical

Components 4 (quadruple)

Component IDs AB

Separation 2.8″

Companion Mag 7.1

Companion Sp A2

Position Angle 344°

Star Colors A: Red B: White

Discoverer STF 997

Notes

AB fixed.

Separation over time

Measured 1830 → 2021 (191 y)

Separation drift 3.6" → 2.8" (-0.80")

Rate -0.0042" / y

PA drift 341° → 344° (+3°, +0.016°/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.