When is the best time to observe 3 Pegasi?

3 Pegasi is best observed from July through September, with peak visibility during August when it transits around midnight in the Northern Hemisphere.

Where is 3 Pegasi located in the sky?

3 Pegasi lies in the constellation Pegasus at right ascension 21h 38m and declination +06° 37′.

What telescope do I need to split 3 Pegasi?

Splitting 3 Pegasi requires an aperture of roughly 60 mm or larger — the components are separated by about 38.7″ at magnitudes near 6.2. Larger apertures and steady seeing help resolve the pair cleanly.

3 Pegasi — Double Star in Pegasus

Magnitude 6.2^m DoubleStar Pegasus (Peg) Visible

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Observe

1Physical Properties

Magnitude 6.18

Spectral Type A2V

Star Color White (B-V 0.02)

2Position & Identifiers

RA 21h 37m 43.7s

Dec +06° 37' 06.0"

Constellation Pegasus (Peg)

HR 8265

HIP 106783

HD 205811

SAO 126940

Flamsteed 3 Peg

Double Cat 15147

SIMBAD

3How easy to split?

Primary 6.2 mag Companion 7.5 mag Separation 38.7″

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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 Jul – Sep (peak: Aug)

5Multiple Star System Triple C: optical

Components 3 (triple)

Component IDs AB

Separation 38.7″

Companion Mag 7.5

Position Angle 349°

Star Colors A: White B: Yellow-white

Discoverer STFA 56

Notes

AB CPM. B is 7.65V, +0.37(B-V), -0.01(U-B), F2V; vsini 30k/s.

Separation over time

Measured 1782 → 2020 (238 y)

Separation drift 34.7" → 38.7" (+4.00")

Rate +0.0168" / y

PA drift 353° → 349° (-4°, -0.017°/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.