When is the best time to observe Alpha Microscopii?

Alpha Microscopii is best observed from June through August, with peak visibility during July when it transits around midnight in the Northern Hemisphere.

Where is Alpha Microscopii located in the sky?

Alpha Microscopii lies in the constellation Microscopium at right ascension 20h 50m and declination -33° 47′.

What telescope do I need to split Alpha Microscopii?

Splitting Alpha Microscopii requires an aperture of roughly 60 mm or larger — the components are separated by about 20.2″ at magnitudes near 4.9. The companion is about 5.2 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Alpha Microscopii — Double Star in Microscopium

Magnitude 4.9^m DoubleStar Microscopium (Mic) Visible

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1Physical Properties

Magnitude 4.90

Spectral Type G7III giant

Star Color Orange (B-V 1.00)

Distance 272 ly

2Position & Identifiers

RA 20h 49m 58.1s

Dec -33° 46' 47.0"

Constellation Microscopium (Mic)

HR 7965

HIP 102831

HD 198232

SAO 212472

Bayer Alpha

SIMBAD

3How easy to split?

Primary 4.9 mag Companion 10.1 mag Separation 20.2″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Medium+	Medium	Hard+
150 mm Newton 150mm Newt.	Easy	Easy	Medium+
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 Jun – Aug (peak: Jul)

5Multiple Star System

Separation 20.2″

Companion Mag 10.1

Position Angle 165°

Star Colors A: Orange

Discoverer HJ 5224

Separation over time

Measured 1834 → 2010 (176 y)

Separation drift 27.5" → 20.2" (-7.30")

Rate -0.0415" / y

PA drift 168° → 165° (-3°, -0.017°/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.