When is the best time to observe Alkalurops?

Alkalurops is best observed from April through June, with peak visibility during May when it transits around midnight in the Northern Hemisphere.

Where is Alkalurops located in the sky?

Alkalurops lies in the constellation Boötes at right ascension 15h 24m and declination +37° 23′.

What telescope do I need to split Alkalurops?

Splitting Alkalurops requires an aperture of roughly 60 mm or larger — the components are separated by about 109.2″ at magnitudes near 4.3. Larger apertures and steady seeing help resolve the pair cleanly.

Alkalurops — Double Star in Boötes

HIP 75411; Mu Bootis; 51 Bootis

Observable Double Star Good (50/100)

Sep: 109.2", Companion: mag 7.1

Magnitude 4.3^m DoubleStar Boötes (Boo) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.31

Variable Type Delta Scuti (Pulsating)

Spectral Type F2IVa supergiant

Star Color Yellow-white (B-V 0.31)

Distance 84 ly

2Position & Identifiers

RA 15h 24m 29.4s

Dec +37° 22' 38.0"

Constellation Boötes (Boo)

HR 5733

HIP 75411

HD 137391

SAO 64686

Bayer Mu

Flamsteed 51 Boo

Double Cat 9626

SIMBAD Wikipedia

3How easy to split?

Primary 4.3 mag Companion 7.1 mag Separation 109.2″

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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 Apr – Jun (peak: May)

5Multiple Star System Triple

Components 3 (triple)

Component IDs AxBC

Separation 109.2″

Companion Mag 7.1

Companion Sp G0V

Position Angle 170°

Star Colors A: Yellow-white C: Yellow

Discoverer STFA 28

Notes

Probably binary with HR 5734, a close binary ADS 9626BC.

Separation over time

Measured 1780 → 2023 (243 y)

Separation drift 128.0" → 109.2" (-18.80")

Rate -0.0774" / y

PA drift 170° → 170° (+0°, +0.000°/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.