When is the best time to observe HIP 20161?

HIP 20161 is best observed from October through December, with peak visibility during November when it transits around midnight in the Northern Hemisphere.

Where is HIP 20161 located in the sky?

HIP 20161 lies in the constellation Horologium at right ascension 04h 19m and declination -44° 16′.

What telescope do I need to split HIP 20161?

Splitting HIP 20161 requires an aperture of roughly 60 mm or larger — the components are separated by about 70.3″ at magnitudes near 5.3. The companion is about 3.3 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 20161 — Double Star in Horologium

Observable Double Star Good (47/100)

Sep: 70.3", Companion: mag 8.6

Magnitude 5.3^m DoubleStar Horologium (Hor) Visible

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Observe

1Physical Properties

Magnitude 5.34

Spectral Type K2III giant

Star Color Orange (B-V 1.08)

Distance 652 ly

2Position & Identifiers

RA 04h 19m 16.6s

Dec -44° 16' 05.0"

Constellation Horologium (Hor)

HR 1364

HIP 20161

HD 27588

SAO 216749

SIMBAD

3How easy to split?

Primary 5.3 mag Companion 8.6 mag Separation 70.3″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Medium+
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 Oct – Dec (peak: Nov)

5Multiple Star System

Separation 70.3″

Companion Mag 8.6

Position Angle 115°

Star Colors A: Orange

Discoverer HJ 3643

Notes

CPM. Companion G0V.

Separation over time

Measured 1836 → 2016 (180 y)

Separation drift 70.0" → 70.3" (+0.30")

Rate +0.0017" / y

PA drift 116° → 115° (-1°, -0.006°/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.