When is the best time to observe Alniyat?

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

Where is Alniyat located in the sky?

Alniyat lies in the constellation Scorpius at right ascension 16h 21m and declination -25° 36′.

What telescope do I need to split Alniyat?

Splitting Alniyat requires an aperture of roughly 60 mm or larger — the components are separated by about 20.5″ at magnitudes near 2.9. The companion is about 5.5 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Alniyat — Double Star in Scorpius

HIP 80112; Sigma Scorpii; 20 Scorpii

Magnitude 2.9^m DoubleStar Scorpius (Sco) Visible

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About Alniyat

Description

Alniyat is a blue giant of spectral type B1III at magnitude 2.89 in Scorpius. Located about 568 light-years from Earth, it has a luminosity of roughly 18,000 times solar. It lies near the heart of the Scorpion, close to brilliant Antares, and is actually a quadruple star system.

Observing Tips

Alniyat sits just north of Antares in the body of Scorpius, forming part of the trio of stars around the Scorpion's heart. Its blue-white color provides a dramatic contrast with the deep red Antares. A faint companion is visible in telescopes. Best observed June through August.

History

The name Alniyat comes from the Arabic 'al-niyat,' meaning 'the arteries,' shared with Tau Sco — both flank the 'heart' star Antares. The proximity of bright blue and red stars in this region makes it one of the most colorful naked-eye areas of the sky.

Fun Facts

The trio of Alniyat, Antares, and Tau Sco creates one of the most vivid color groupings in the sky — deep red Antares flanked by brilliant blue companions. This color contrast is immediately visible to the naked eye.

Observe

1Physical Properties

Magnitude 2.89

Range 2.86 - 2.94

Period 5.9 hours

Variable Type Beta Cephei (Pulsating)

Spectral Type B1 III giant

Star Color Blue (B-V 0.13) (reddened by dust)

Distance 683 ly

2Position & Identifiers

RA 16h 21m 11.3s

Dec -25° 35' 34.0"

Constellation Scorpius (Sco)

HR 6084

HIP 80112

HD 147165

SAO 184336

Bayer Sigma

Flamsteed 20 Sco

Variable ID Sig Sco

Double Cat 10009

SIMBAD Wikipedia

3How easy to split?

Primary 2.9 mag Companion 8.4 mag Separation 20.5″

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Medium+
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

Set a location in User Settings to see visibility data.

Best season Apr – Jun (peak: May)

5Light Curve

6Multiple Star System Quadruple

Components 4 (quadruple)

Component IDs O

Separation 20.5″

Companion Mag 8.4

Companion Sp B8V

Position Angle 269°

Star Colors A: Blue (reddened by dust) B: Blue-white

Discoverer H 4 121

Notes

B, 8.26V, +0.25(B-V), -0.23(U-B), B9.5V at 20", optical; vsini : 54k/s. The visual primary is triple: SB, 3.3, 5.3v, | sep. 0.0005" and 5.5v at 0.49", discovered by occultation.

Separation over time

Measured 1783 → 2019 (236 y)

Separation drift 21.7" → 20.5" (-1.20")

Rate -0.0051" / y

PA drift 270° → 269° (-1°, -0.004°/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.

Eyepiece View

Telescope Eyepiece

80x Dawes: 1.9″ TFOV: 0.6°

Seeing

Scale Realistic = true angular size

A: 2.9 · B: 8.4 · Sep: 20.5″ · PA: 269° · N up, E right

Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″

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Spectral Classification

Hertzsprung-Russell Diagram

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Stellar Lifecycle

Blackbody Spectrum

Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

Stellar Fusion

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16Stellar Notes

Variable Star

Beta C 2.94 - 3.06B. Multiple periods, 0.2468429, 0.239671, 8.2, and 33.1d. Surrounded by HII region. Primary | period varies in period of 23.2y with an amp. of 0.7 sec. Occultations indicate the variable has a 2.2 mag. fainter | companion at 0".49. The duplicity had been suspected from occultations as early as 1860. Orbital period probably over | 112 yrs. UV observations indicate temperature varies by 2510K and ratio max. to min. radius by 1.095.

Spectroscopic Binary

ADS 10009A, 34.23d, K 34.0k/s, V0 +2.5k/s, asini 14.9.

Color

Color excess E(B-V) = +0.40. Reddened star.

Group/Cluster

Sco OB2; Sco-Cen cluster; upper Sco region; HII region S9; in reflection nebula; assoc. Sco R1.

Spectral

Stationary Ca lines. Although this star is an MK standard for class B1III, it is a variable, a multiple star, and is | situated in reflection nebulosity. Component A has also been classified as B2III and B2IV; component B as B9V, B9.5V, | and B8Vp. From scanner studies of composite spectra, Beavers (ApJS, 44, 489, 1980) finds ADS 10009A can be | resolved into O9.5 and B7 with a magnitude difference of 1.6V.

Radial Velocity

ADS 10009B, -6k/s.

Alternative Names

Alniyat; Al Niyat. Name applies to pair with HR 6165.