When is the best time to observe HP Canis Majoris?

HP Canis Majoris is best observed from November through January, with peak visibility during December when it transits around midnight in the Northern Hemisphere.

Where is HP Canis Majoris located in the sky?

HP Canis Majoris lies in the constellation Canis Major at right ascension 06h 46m and declination -30° 57′.

What telescope do I need to split HP Canis Majoris?

Splitting HP Canis Majoris requires an aperture of roughly 80 mm or larger — the components are separated by about 5.0″ at magnitudes near 5.8. Larger apertures and steady seeing help resolve the pair cleanly.

HP Canis Majoris — Double Star in Canis Major

Observable Double Star Good (52/100)

Sep: 5.0", Companion: mag 8.2

DoubleStar Canis Major (CMa) Visible

Star Map + List + Plan Star Hop

Observe

1Physical Properties

Magnitude 5.80

Range 5.33 - 5.81

Period 19.0 hours

Variable Type Gamma Cassiopeiae (Eruptive Be Star)

Spectral Type B2III

Star Color Blue (B-V -0.19)

Distance 652 ly

2Position & Identifiers

RA 06h 45m 31.3s

Dec -30° 56' 56.0"

Constellation Canis Major (CMa)

HR 2501

HIP 32385

HD 49131

Variable ID HP CMa

SIMBAD

3How easy to split?

Primary 5.8 mag Companion 8.2 mag Separation 5.0″

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Medium+	Medium+	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

Set a location in User Settings to see visibility data.

Best season Nov – Jan (peak: Dec)

5Light Curve

6Multiple Star System

Separation 5.0″

Companion Mag 8.2

Position Angle 223°

Star Colors A: Blue B: White

Discoverer HJ 3891

Separation over time

Measured 1838 → 2015 (177 y)

Separation drift 5.0" → 5.0" (+0.00")

Rate +0.0000" / y

PA drift 222° → 223° (+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.