When is the best time to observe HIP 42504?

HIP 42504 is best observed from December through February, with peak visibility during January when it transits around midnight in the Northern Hemisphere.

Where is HIP 42504 located in the sky?

HIP 42504 lies in the constellation Vela at right ascension 08h 40m and declination -53° 03′.

What telescope do I need to split HIP 42504?

Splitting HIP 42504 requires an aperture of roughly 60 mm or larger — the components are separated by about 16.8″ at magnitudes near 5.2. The companion is about 3.5 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 42504 — Double Star in Vela

Observable Double Star Good (58/100)

Sep: 16.8", Companion: mag 8.7

Magnitude 5.2^m DoubleStar Vela (Vel) Visible

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Observe

1Physical Properties

Magnitude 5.19

Variable Type Ellipsoidal Variable

Spectral Type B4IV subgiant

Star Color Blue-white (B-V -0.14)

2Position & Identifiers

RA 08h 39m 57.6s

Dec -53° 03' 18.0"

Constellation Vela (Vel)

HR 3442

HIP 42504

HD 74146

SAO 236157

SIMBAD

3How easy to split?

Primary 5.2 mag Companion 8.7 mag Separation 16.8″

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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 Dec – Feb (peak: Jan)

5Multiple Star System

Separation 16.8″

Companion Mag 8.7

Position Angle 30°

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

Discoverer HJ 4126

Notes

CPM? Companion F0IV.

Separation over time

Measured 1834 → 2010 (176 y)

Separation drift 15.0" → 16.8" (+1.80")

Rate +0.0102" / y

PA drift 28° → 30° (+2°, +0.011°/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.