When is the best time to observe 16 Persei?

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

Where is 16 Persei located in the sky?

16 Persei lies in the constellation Perseus at right ascension 02h 51m and declination +38° 19′.

What telescope do I need to split 16 Persei?

Splitting 16 Persei requires an aperture of roughly 60 mm or larger — the components are separated by about 231.3″ at magnitudes near 4.2. The companion is about 6.2 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

16 Persei — Double Star in Perseus

DoubleStar Perseus (Per) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.23

Variable Type Delta Scuti (Pulsating)

Spectral Type F2III

Star Color Yellow-white (B-V 0.34)

Distance 136 ly

2Position & Identifiers

RA 02h 50m 35.1s

Dec +38° 19' 07.0"

Constellation Perseus (Per)

HR 840

HIP 13254

HD 17584

Flamsteed 16 Per

SIMBAD

3How easy to split?

Primary 4.2 mag Companion 10.4 mag Separation 231.3″

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

Easy Medium Hard Very hard Impossible

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

4Visibility

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Best season Sep – Nov (peak: Oct)

5Multiple Star System Triple

Components 3 (triple)

Component IDs AC

Separation 231.3″

Companion Mag 10.4

Position Angle 149°

Star Colors A: Yellow-white

Discoverer STT 556

Separation over time

Measured 1857 → 2014 (157 y)

Separation drift 262.9" → 231.3" (-31.60")

Rate -0.2013" / y

PA drift 144° → 149° (+5°, +0.032°/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.