When is the best time to observe 4 Vulpeculae?

4 Vulpeculae is best observed from June through August, with peak visibility during July when it transits around midnight in the Northern Hemisphere.

Where is 4 Vulpeculae located in the sky?

4 Vulpeculae lies in the constellation Vulpecula at right ascension 19h 25m and declination +19° 48′.

What telescope do I need to split 4 Vulpeculae?

Splitting 4 Vulpeculae requires an aperture of roughly 60 mm or larger — the components are separated by about 13.5″ at magnitudes near 5.2. The companion is about 4.8 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

4 Vulpeculae — Double Star in Vulpecula

Magnitude 5.2^m DoubleStar Vulpecula (Vul) Visible

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Observe

1Physical Properties

Magnitude 5.16

Spectral Type K0III giant

Star Color Orange (B-V 0.98)

Distance 125 ly

2Position & Identifiers

RA 19h 25m 28.6s

Dec +19° 47' 55.0"

Constellation Vulpecula (Vul)

HR 7385

HIP 95498

HD 182762

SAO 104818

Flamsteed 4 Vul

Double Cat 12425

SIMBAD

3How easy to split?

Primary 5.2 mag Companion 10.0 mag Separation 13.5″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Medium+	Medium	Hard+
150 mm Newton 150mm Newt.	Easy	Easy	Medium+
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 Jun – Aug (peak: Jul)

5Multiple Star System Triple optical

Components 3 (triple)

Component IDs AB

Separation 13.5″

Companion Mag 10.0

Position Angle 87°

Star Colors A: Orange

Discoverer HJ 2871

Notes

Both companions optical.

Separation over time

Measured 1831 → 2016 (185 y)

Separation drift 27.5" → 13.5" (-14.00")

Rate -0.0757" / y

PA drift 111° → 87° (-24°, -0.130°/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.