When is the best time to observe Tau Tauri?

Tau Tauri is best observed from October through December, with peak visibility during November when it transits around midnight in the Northern Hemisphere.

Where is Tau Tauri located in the sky?

Tau Tauri lies in the constellation Taurus at right ascension 04h 42m and declination +22° 57′.

What telescope do I need to split Tau Tauri?

Splitting Tau Tauri requires an aperture of roughly 60 mm or larger — the components are separated by about 62.5″ at magnitudes near 4.3. Larger apertures and steady seeing help resolve the pair cleanly.

Tau Tauri — Double Star in Taurus

Observable Double Star Good (53/100)

Sep: 62.5", Companion: mag 7.0

Magnitude 4.3^m DoubleStar Taurus (Tau) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.28

Spectral Type B3V

Star Color Blue (B-V -0.13)

Distance 192 ly

2Position & Identifiers

RA 04h 42m 14.7s

Dec +22° 57' 25.0"

Constellation Taurus (Tau)

HR 1497

HIP 21881

HD 29763

SAO 76721

Bayer Tau

Flamsteed 94 Tau

SIMBAD

3How easy to split?

Primary 4.3 mag Companion 7.0 mag Separation 62.5″

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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 Oct – Dec (peak: Nov)

5Multiple Star System Quintuple

Components 5 (quintuple)

Separation 62.5″

Companion Mag 7.0

Position Angle 214°

Star Colors A: Blue

Discoverer S 455

Notes

AB CPM, 4.3, 8.9v sep. 0.1", 28y? C, 7.3A1V at 63" vsini 100k/s, physical. D. W. Dunham gives 4.9, 5.6v sep. 0.1" and | 4.9, 6.4 sep. 0.0005".

Separation over time

Measured 1777 → 2017 (240 y)

Separation drift 60.0" → 62.5" (+2.50")

Rate +0.0104" / y

PA drift 212° → 214° (+2°, +0.008°/y)

Slow change over generations — observable in lifetime comparisons.

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.