When is the best time to observe 39 Ophiuchi?

39 Ophiuchi is best observed from May through July, with peak visibility during June when it transits around midnight in the Northern Hemisphere.

Where is 39 Ophiuchi located in the sky?

39 Ophiuchi lies in the constellation Ophiuchus at right ascension 17h 18m and declination -24° 17′.

What telescope do I need to split 39 Ophiuchi?

Splitting 39 Ophiuchi requires an aperture of roughly 60 mm or larger — the components are separated by about 10.7″ at magnitudes near 5.2. Larger apertures and steady seeing help resolve the pair cleanly.

39 Ophiuchi — Double Star in Ophiuchus

Observable Double Star Excellent (73/100)

Sep: 10.7", Companion: mag 6.6

Magnitude 5.2^m DoubleStar Ophiuchus (Oph) Visible

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Observe

1Physical Properties

Magnitude 5.20

Spectral Type K0II-III bright giant

Star Color Orange (B-V 1.10)

Distance 251 ly

2Position & Identifiers

RA 17h 18m 00.7s

Dec -24° 17' 13.0"

Constellation Ophiuchus (Oph)

HR 6424

HIP 84626

HD 156349

SAO 185238

Flamsteed 39 Oph

Double Cat 10442

SIMBAD

3How easy to split?

Primary 5.2 mag Companion 6.6 mag Separation 10.7″

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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 May – Jul (peak: Jun)

5Multiple Star System

Separation 10.7″

Companion Mag 6.6

Companion Sp F6IV

Position Angle 355°

Star Colors A: Orange B: Yellow

Discoverer H 3 25

Notes

Binary with HR 6425.

Separation over time

Measured 1780 → 2024 (244 y)

Separation drift 10.0" → 10.7" (+0.70")

Rate +0.0029" / y

PA drift 357° → 355° (-2°, -0.008°/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.