When is the best time to observe Arneb?

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

Where is Arneb located in the sky?

Arneb lies in the constellation Lepus at right ascension 05h 33m and declination -17° 49′.

What telescope do I need to split Arneb?

Splitting Arneb requires an aperture of roughly 60 mm or larger — the components are separated by about 35.4″ at magnitudes near 2.6. The companion is about 8.6 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Arneb — Double Star in Lepus

HIP 25985; Alpha Leporis; 11 Leporis

Magnitude 2.6^m DoubleStar Lepus (Lep) Visible

Star Map + List + Plan

About Arneb

Description

Arneb is a yellow-white supergiant of spectral type F0Ib at magnitude 2.58, the brightest star in Lepus (the Hare). Located about 2,200 light-years from Earth, it is intrinsically very luminous — roughly 32,000 times the Sun's luminosity. It is one of the most luminous F-type supergiants visible to the naked eye.

Observing Tips

Arneb is the brightest star in Lepus, the small constellation directly below Orion. It is easy to find as the most prominent star in the group just south of Rigel and Saiph. Best observed December through March when Orion and Lepus are well-placed.

History

The name Arneb comes from the Arabic 'al-arnab,' meaning 'the hare.' Lepus was placed at Orion's feet because the mythological hunter was fond of hunting hares. Despite its modest naked-eye appearance, Arneb is a massive and distant supergiant.

Fun Facts

Arneb is so distant and luminous that if it were at Sirius's distance, it would outshine Venus. It is a rare naked-eye example of an F-type supergiant — most supergiants visible to the naked eye are either hotter (blue) or cooler (red).

Observe

1Physical Properties

Magnitude 2.58

Spectral Type F0Ib supergiant

Star Color Yellow-white (B-V 0.21)

Distance 2,195 ly

2Position & Identifiers

RA 05h 32m 43.8s

Dec -17° 49' 20.0"

Constellation Lepus (Lep)

HR 1865

HIP 25985

HD 36673

SAO 150547

Bayer Alpha

Flamsteed 11 Lep

Double Cat 4146

SIMBAD Wikipedia

3How easy to split?

Primary 2.6 mag Companion 11.2 mag Separation 35.4″

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard+	Hard	V. hard+
150 mm Newton 150mm Newt.	Medium+	Medium	Hard+
Celestron C8 (203 mm SCT) C8 203mm	Easy	Medium+	Medium

Easy Medium Hard Very hard Impossible

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

4Visibility

Set a location in User Settings to see visibility data.

Best season Nov – Jan (peak: Dec)

5Multiple Star System Triple C: optical

Components 3 (triple)

Component IDs AB

Separation 35.4″

Companion Mag 11.2

Position Angle 157°

Star Colors A: Yellow-white

Discoverer HJ 3766

Separation over time

Measured 1835 → 2015 (180 y)

Separation drift 25.0" → 35.4" (+10.40")

Rate +0.0578" / y

PA drift 155° → 157° (+2°, +0.011°/y)

Apparent motion is significant on a human timescale — worth revisiting in a decade.

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.