When is the best time to observe Pi Arietis?

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

Where is Pi Arietis located in the sky?

Pi Arietis lies in the constellation Aries at right ascension 02h 49m and declination +17° 28′.

What telescope do I need to split Pi Arietis?

Splitting Pi Arietis requires an aperture of roughly 100 mm or larger — the components are separated by about 3.3″ at magnitudes near 5.2. Larger apertures and steady seeing help resolve the pair cleanly.

Pi Arietis — Double Star in Aries

Observable Double Star Excellent (60/100)

Sep: 3.3", Companion: mag 8.0

Magnitude 5.2^m DoubleStar Aries (Ari) Visible

Star Map + List + Plan Star Hop

Observe

1Physical Properties

Magnitude 5.22

Range 5.31 - 5.34

Period 3.8 days

Variable Type Ellipsoidal Variable

Spectral Type B6V

Star Color Blue-white (B-V -0.06)

2Position & Identifiers

RA 02h 49m 17.5s

Dec +17° 27' 51.0"

Constellation Aries (Ari)

HR 836

HIP 13165

HD 17543

SAO 93127

Bayer Pi

Flamsteed 42 Ari

Double Cat 2151

SIMBAD

3How easy to split?

Primary 5.2 mag Companion 8.0 mag Separation 3.3″

Sign in and configure your equipment and default location to see a personalized row.

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

Set a location in User Settings to see visibility data.

Best season Sep – Nov (peak: Oct)

5Light Curve

6Multiple Star System Quadruple D: optical

Components 4 (quadruple)

Component IDs A

Separation 3.3″

Companion Mag 8.0

Position Angle 118°

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

Discoverer STF 311

Notes

AB CPM. B 8.8v, A0Vp at 3.2", RV -21k/s, probably optical; C 10.72V, +0.60(B-V), +0.60(U-B), F8V at 25". A is close SB | pair with computed sep. 0.00004".

Separation over time

Measured 1821 → 2020 (199 y)

Separation drift 3.1" → 3.3" (+0.20")

Rate +0.0010" / y

PA drift 124° → 118° (-6°, -0.030°/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.