When is the best time to observe Asterope?

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

Where is Asterope located in the sky?

Asterope lies in the constellation Taurus at right ascension 03h 46m and declination +24° 33′.

What telescope do I need to split Asterope?

Splitting Asterope requires an aperture of roughly 60 mm or larger — the components are separated by about 149.6″ at magnitudes near 5.8. Larger apertures and steady seeing help resolve the pair cleanly.

Asterope — Double Star in Taurus

HIP 17579; 21 Tauri

Observable Double Star Good (47/100)

Sep: 149.6", Companion: mag 6.4

Magnitude 5.8^m DoubleStar Taurus (Tau) Visible

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Observe

1Physical Properties

Magnitude 5.76

Spectral Type B8V

Star Color Blue-white (B-V -0.04)

2Position & Identifiers

RA 03h 45m 54.4s

Dec +24° 33' 17.0"

Constellation Taurus (Tau)

HR 1151

HIP 17579

HD 23432

SAO 76159

Flamsteed 21 Tau

SIMBAD Wikipedia

3How easy to split?

Primary 5.8 mag Companion 6.4 mag Separation 149.6″

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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

Separation 149.6″

Companion Mag 6.4

Position Angle 130°

Star Colors A: Blue-white B: White

Discoverer HJL1026

Separation over time

Measured 1894 → 2015 (121 y)

Separation drift 149.8" → 149.6" (-0.20")

Rate -0.0017" / y

PA drift 129° → 130° (+1°, +0.008°/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.