When is the best time to observe 11 Arietis?

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

Where is 11 Arietis located in the sky?

11 Arietis lies in the constellation Aries at right ascension 02h 07m and declination +25° 42′.

What telescope do I need to split 11 Arietis?

Splitting 11 Arietis requires an aperture of roughly 480 mm or larger — the components are separated by about 1.8″ at magnitudes near 6.2. The companion is about 5.3 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

11 Arietis — Double Star in Aries

Magnitude 6.2^m DoubleStar Aries (Ari) Visible

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Observe

1Physical Properties

Magnitude 6.15

Spectral Type B9IV-Vn subgiant

Star Color Blue-white (B-V -0.03)

2Position & Identifiers

RA 02h 06m 49.2s

Dec +25° 42' 17.0"

Constellation Aries (Ari)

HR 615

HIP 9859

HD 12885

SAO 75149

Flamsteed 11 Ari

Double Cat 1658

SIMBAD

3How easy to split?

Primary 6.2 mag Companion 11.5 mag Separation 1.8″

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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.	V. hard	V. hard	V. hard
Celestron C8 (203 mm SCT) C8 203mm	V. hard+	V. hard+	V. 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 480 mm reflector.

4Visibility

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Best season Sep – Nov (peak: Oct)

5Multiple Star System

Separation 1.8″

Companion Mag 11.5

Position Angle 343°

Star Colors A: Blue-white

Discoverer HO 312

Separation over time

Measured 1890 → 2021 (131 y)

Separation drift 1.1" → 1.8" (+0.70")

Rate +0.0053" / y

PA drift 330° → 343° (+13°, +0.099°/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.