When is the best time to observe HIP 42549?

HIP 42549 is best observed from December through February, with peak visibility during January when it transits around midnight in the Northern Hemisphere.

Where is HIP 42549 located in the sky?

HIP 42549 lies in the constellation Cancer at right ascension 08h 40m and declination +19° 40′.

What telescope do I need to split HIP 42549?

Splitting HIP 42549 requires an aperture of roughly 60 mm or larger — the components are separated by about 63.2″ at magnitudes near 6.4. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 42549 — Double Star in Cancer

Magnitude 6.4^m DoubleStar Cancer (Cnc) Visible

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Observe

1Physical Properties

Magnitude 6.44

Spectral Type G9III giant

Star Color Orange (B-V 1.02)

2Position & Identifiers

RA 08h 40m 22.1s

Dec +19° 40' 12.0"

Constellation Cancer (Cnc)

HR 3428

HIP 42549

HD 73710

SAO 98021

Double Cat 6921

SIMBAD

3How easy to split?

Primary 6.4 mag Companion 7.6 mag Separation 63.2″

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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 Dec – Feb (peak: Jan)

5Multiple Star System Quadruple

Components 4 (quadruple)

Component IDs AC

Separation 63.2″

Companion Mag 7.6

Position Angle 343°

Star Colors A: Orange

Discoverer STF1254

Notes

ACD a physical group: C, 7.70V, +0.20(B-V), +0.16(U-B), Am, vsini <45k/s. D, 9.39V, +0.41(B-V), +0.03(U-B), F5V at | 83". B, 10.37V, +0.59(B-V), +0.11(U-B), G0IV-V at 21", CPM.

Separation over time

Measured 1863 → 2023 (160 y)

Separation drift 63.4" → 63.2" (-0.20")

Rate -0.0012" / y

PA drift 342° → 343° (+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.