When is the best time to observe HIP 51561?

HIP 51561 is best observed from January through March, with peak visibility during February when it transits around midnight in the Northern Hemisphere.

Where is HIP 51561 located in the sky?

HIP 51561 lies in the constellation Vela at right ascension 10h 32m and declination -45° 04′.

What telescope do I need to split HIP 51561?

Splitting HIP 51561 requires an aperture of roughly 60 mm or larger — the components are separated by about 13.7″ at magnitudes near 5.7. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 51561 — Double Star in Vela

Observable Double Star Excellent (67/100)

Sep: 13.7", Companion: mag 6.0

Magnitude 5.7^m DoubleStar Vela (Vel) Visible

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Observe

1Physical Properties

Magnitude 5.74

Spectral Type B6II bright giant

Star Color Blue-white (B-V -0.15)

2Position & Identifiers

RA 10h 31m 57.5s

Dec -45° 04' 00.0"

Constellation Vela (Vel)

HR 4135

HIP 51561

HD 91355

SAO 222126

SIMBAD

3How easy to split?

Primary 5.7 mag Companion 6.0 mag Separation 13.7″

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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 Jan – Mar (peak: Feb)

5Multiple Star System

Separation 13.7″

Companion Mag 6.0

Position Angle 218°

Star Colors A: Blue-white B: Blue-white

Discoverer PZ 3

Notes

Fixed with HR 4136. Mag. and color for combined light, 5.16V, -0.15(B-V), -0.62(U-B).

Separation over time

Measured 1826 → 2015 (189 y)

Separation drift 14.9" → 13.7" (-1.20")

Rate -0.0063" / y

PA drift 221° → 218° (-3°, -0.016°/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.