When is the best time to observe Xi Ophiuchi?

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

Where is Xi Ophiuchi located in the sky?

Xi Ophiuchi lies in the constellation Ophiuchus at right ascension 17h 21m and declination -21° 07′.

What telescope do I need to split Xi Ophiuchi?

Splitting Xi Ophiuchi requires an aperture of roughly 100 mm or larger — the components are separated by about 4.1″ at magnitudes near 4.4. The companion is about 4.5 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Xi Ophiuchi — Double Star in Ophiuchus

Observable Double Star Good (56/100)

Sep: 4.1", Companion: mag 8.9

Magnitude 4.4^m DoubleStar Ophiuchus (Oph) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.39

Spectral Type F1III-IV giant

Star Color Yellow-white (B-V 0.39)

Distance 53 ly

2Position & Identifiers

RA 17h 21m 00.2s

Dec -21° 06' 46.0"

Constellation Ophiuchus (Oph)

HR 6445

HIP 84893

HD 156897

SAO 185296

Bayer Xi

Flamsteed 40 Oph

SIMBAD

3How easy to split?

Primary 4.4 mag Companion 8.9 mag Separation 4.1″

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

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 4.1″

Companion Mag 8.9

Position Angle 26°

Star Colors A: Yellow-white B: Orange

Discoverer DON 832

Separation over time

Measured 1932 → 2016 (84 y)

Separation drift 2.5" → 4.1" (+1.60")

Rate +0.0190" / y

PA drift 66° → 26° (-40°, -0.476°/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.