When is the best time to observe HR 6660?

HR 6660 is best observed from May through July, with peak visibility during June when it transits around midnight in the Northern Hemisphere.

Where is HR 6660 located in the sky?

HR 6660 lies in the constellation Scorpius at right ascension 17h 54m and declination -34° 47′.

What telescope do I need to split HR 6660?

Splitting HR 6660 requires an aperture of roughly 60 mm or larger — the components are separated by about 34.7″ at magnitudes near 6.4. Larger apertures and steady seeing help resolve the pair cleanly.

HR 6660 — Double Star in Scorpius

Magnitude 6.4^m DoubleStar Scorpius (Sco) Visible

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Observe

1Physical Properties

Magnitude 6.38

Spectral Type B9V

Star Color Blue-white (B-V 0.00)

2Position & Identifiers

RA 17h 53m 45.5s

Dec -34° 47' 09.0"

Constellation Scorpius (Sco)

HR 6660

HD 162678

SAO 209425

3How easy to split?

Primary 6.4 mag Companion 7.0 mag Separation 34.7″

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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 34.7″

Companion Mag 7.0

Position Angle 209°

Star Colors A: Blue-white B: White

Discoverer WFC 201

Separation over time

Measured 1911 → 2000 (89 y)

Separation drift 34.5" → 34.7" (+0.20")

Rate +0.0022" / y

PA drift 209° → 209° (+0°, +0.000°/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.