When is the best time to observe HIP 77645?

HIP 77645 is best observed from April through June, with peak visibility during May when it transits around midnight in the Northern Hemisphere.

Where is HIP 77645 located in the sky?

HIP 77645 lies in the constellation Norma at right ascension 15h 51m and declination -55° 03′.

What telescope do I need to split HIP 77645?

Splitting HIP 77645 requires an aperture of roughly 60 mm or larger — the components are separated by about 16.2″ at magnitudes near 5.7. 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 77645 — Double Star in Norma

Magnitude 5.7^m DoubleStar Norma (Nor) Visible

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Observe

1Physical Properties

Magnitude 5.73

Spectral Type B2II bright giant

Star Color White (B-V 0.06)

2Position & Identifiers

RA 15h 51m 06.8s

Dec -55° 03' 21.0"

Constellation Norma (Nor)

HR 5873

HIP 77645

HD 141318

SAO 243044

SIMBAD

3How easy to split?

Primary 5.7 mag Companion 9.1 mag Separation 16.2″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	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

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Best season Apr – Jun (peak: May)

5Multiple Star System Quadruple

Components 4 (quadruple)

Component IDs AB

Separation 16.2″

Companion Mag 9.1

Position Angle 12°

Star Colors A: White B: Yellow

Discoverer DUN 193

Notes

Component B, K0V. Third component optical.

Separation over time

Measured 1836 → 2015 (179 y)

Separation drift 22.5" → 16.2" (-6.30")

Rate -0.0352" / y

PA drift 19° → 12° (-7°, -0.039°/y)

Apparent motion is significant on a human timescale — worth revisiting in a decade.

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.