When is the best time to observe Eta Piscis Austrini?

Eta Piscis Austrini is best observed from July through September, with peak visibility during August when it transits around midnight in the Northern Hemisphere.

Where is Eta Piscis Austrini located in the sky?

Eta Piscis Austrini lies in the constellation Piscis Austrinus at right ascension 22h 01m and declination -28° 27′.

What telescope do I need to split Eta Piscis Austrini?

Splitting Eta Piscis Austrini requires an aperture of roughly 150 mm or larger — the components are separated by about 1.9″ at magnitudes near 5.4. Larger apertures and steady seeing help resolve the pair cleanly.

Eta Piscis Austrini — Double Star in Piscis Austrinus

Observable Double Star Fair (27/100)

Sep: 1.9", Companion: mag 6.8

Magnitude 5.4^m DoubleStar Piscis Austrinus (PsA) Visible

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Observe

1Physical Properties

Magnitude 5.42

Spectral Type B8V

Star Color Blue-white (B-V -0.09)

Distance 297 ly

2Position & Identifiers

RA 22h 00m 50.2s

Dec -28° 27' 13.0"

Constellation Piscis Austrinus (PsA)

HR 8386

HIP 108661

HD 209014

SAO 190822

Bayer Eta

Flamsteed 12 PsA

Double Cat 15536

SIMBAD

3How easy to split?

Primary 5.4 mag Companion 6.8 mag Separation 1.9″

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

5Multiple Star System

Separation 1.9″

Companion Mag 6.8

Position Angle 113°

Star Colors A: Blue-white B: White

Discoverer BU 276

Separation over time

Measured 1874 → 2017 (143 y)

Separation drift 1.8" → 1.9" (+0.10")

Rate +0.0007" / y

PA drift 120° → 113° (-7°, -0.049°/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.