When is the best time to observe HIP 51658?

HIP 51658 is best observed from January through March, with peak visibility during February when it transits around midnight in the Northern Hemisphere.

Where is HIP 51658 located in the sky?

HIP 51658 lies in the constellation Ursa Major at right ascension 10h 33m and declination +40° 26′.

What telescope do I need to split HIP 51658?

Splitting HIP 51658 requires an aperture of roughly 60 mm or larger — the components are separated by about 16.9″ at magnitudes near 4.8. The companion is about 6.8 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 51658 — Double Star in Ursa Major

Magnitude 4.8^m DoubleStar Ursa Major (UMa) Visible

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Observe

1Physical Properties

Magnitude 4.75

Spectral Type A7IV subgiant

Star Color Yellow-white (B-V 0.23)

Distance 105 ly

2Position & Identifiers

RA 10h 33m 13.9s

Dec +40° 25' 32.0"

Constellation Ursa Major (UMa)

HR 4132

HIP 51658

HD 91312

SAO 43379

Double Cat 7826

SIMBAD

3How easy to split?

Primary 4.8 mag Companion 11.6 mag Separation 16.9″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard	V. hard+	V. hard
150 mm Newton 150mm Newt.	Medium	Medium	Hard+
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 Jan – Mar (peak: Feb)

5Multiple Star System B,C: optical

Separation 16.9″

Companion Mag 11.6

Position Angle 5°

Star Colors A: Yellow-white

Discoverer HJ 2534

Notes

Visual companion optical.

Separation over time

Measured 1831 → 2023 (192 y)

Separation drift 25.0" → 16.9" (-8.10")

Rate -0.0422" / y

PA drift 315° → 5° (+50°, +0.260°/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.