When is the best time to observe HIP 57851?

HIP 57851 is best observed from February through April, with peak visibility during March when it transits around midnight in the Northern Hemisphere.

Where is HIP 57851 located in the sky?

HIP 57851 lies in the constellation Musca at right ascension 11h 52m and declination -65° 12′.

What telescope do I need to split HIP 57851?

Splitting HIP 57851 requires an aperture of roughly 150 mm or larger — the components are separated by about 1.4″ at magnitudes near 4.9. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 57851 — Double Star in Musca

Observable Double Star Fair (27/100)

Sep: 1.4", Companion: mag 7.2

Magnitude 4.9^m DoubleStar Musca (Mus) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.90

Spectral Type B4V

Star Color Blue (B-V -0.11)

2Position & Identifiers

RA 11h 51m 51.2s

Dec -65° 12' 22.0"

Constellation Musca (Mus)

HR 4549

HIP 57851

HD 103079

SAO 251617

SIMBAD

3How easy to split?

Primary 4.9 mag Companion 7.3 mag Separation 1.4″

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

5Multiple Star System

Separation 1.4″

Companion Mag 7.2

Position Angle 158°

Star Colors A: Blue B: Yellow-white

Discoverer COO 130

Notes

Combined mag., colors.

Separation over time

Measured 1894 → 2016 (122 y)

Separation drift 2.1" → 1.4" (-0.70")

Rate -0.0057" / y

PA drift 162° → 158° (-4°, -0.033°/y)

Slow change over generations — observable in lifetime comparisons.

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.