When is the best time to observe Epsilon Monocerotis?

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

Where is Epsilon Monocerotis located in the sky?

Epsilon Monocerotis lies in the constellation Monoceros at right ascension 06h 24m and declination +04° 36′.

What telescope do I need to split Epsilon Monocerotis?

Splitting Epsilon Monocerotis requires an aperture of roughly 60 mm or larger — the components are separated by about 12.1″ at magnitudes near 4.4. Larger apertures and steady seeing help resolve the pair cleanly.

Epsilon Monocerotis — Double Star in Monoceros

Observable Double Star Excellent (61/100)

Sep: 12.1", Companion: mag 6.6

Magnitude 4.4^m DoubleStar Monoceros (Mon) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.44

Spectral Type A5IV subgiant

Star Color Yellow-white (B-V 0.18)

Distance 130 ly

2Position & Identifiers

RA 06h 23m 46.1s

Dec +04° 35' 34.0"

Constellation Monoceros (Mon)

HR 2298

HIP 30419

HD 44769

SAO 113810

Bayer Epsilon

Flamsteed 8 Mon

Double Cat 5012

SIMBAD

3How easy to split?

Primary 4.4 mag Companion 6.6 mag Separation 12.1″

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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 Nov – Jan (peak: Dec)

5Multiple Star System Triple C: optical

Components 3 (triple)

Component IDs AB

Separation 12.1″

Companion Mag 6.6

Companion Sp F5V

Position Angle 29°

Star Colors A: Yellow-white B: Yellow-white

Discoverer STF 900

Notes

Binary with HR 2299. Combined light 4.30V, +0.21(B-V). Component C, 12.2v at 93".

Separation over time

Measured 1822 → 2021 (199 y)

Separation drift 13.5" → 12.1" (-1.40")

Rate -0.0070" / y

PA drift 24° → 29° (+5°, +0.025°/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.