When is the best time to observe 27 Hydrae?

27 Hydrae is best observed from January through March, with peak visibility during February when it transits around midnight in the Northern Hemisphere.

Where is 27 Hydrae located in the sky?

27 Hydrae lies in the constellation Hydra at right ascension 09h 20m and declination -09° 33′.

What telescope do I need to split 27 Hydrae?

Splitting 27 Hydrae requires an aperture of roughly 60 mm or larger — the components are separated by about 229.1″ at magnitudes near 4.8. Larger apertures and steady seeing help resolve the pair cleanly.

27 Hydrae — Double Star in Hydra

Observable Double Star Good (45/100)

Sep: 229.1", Companion: mag 7.0

Magnitude 4.8^m DoubleStar Hydra (Hya) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.80

Spectral Type G8III-IV+F5V giant

Star Color Orange (B-V 0.93)

Distance 148 ly

2Position & Identifiers

RA 09h 20m 29.0s

Dec -09° 33' 21.0"

Constellation Hydra (Hya)

HR 3709

HIP 45811

HD 80586

SAO 136768

Flamsteed 27 Hya

Double Cat 7311

SIMBAD

3How easy to split?

Primary 4.8 mag Companion 7.0 mag Separation 229.1″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Easy
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 Jan – Mar (peak: Feb)

5Multiple Star System Triple D: optical

Components 3 (triple)

Component IDs AB

Separation 229.1″

Companion Mag 7.0

Companion Sp F4V

Position Angle 211°

Star Colors A: Orange B: Yellow-white

Discoverer SHJ 105

Notes

AB CPM. BC, 6.87v F5V, 9.0v K2V, sep. 9", physical. B, 7.04V, +0.35(B-V), +0.03(U-B), vsini =<60k/s.

Separation over time

Measured 1893 → 2015 (122 y)

Separation drift 229.0" → 229.1" (+0.10")

Rate +0.0008" / y

PA drift 211° → 211° (+0°, +0.000°/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.