When is the best time to observe Graffias?

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

Where is Graffias located in the sky?

Graffias lies in the constellation Scorpius at right ascension 16h 05m and declination -19° 48′.

What telescope do I need to split Graffias?

Splitting Graffias requires an aperture beyond typical amateur scopes — even 500 mm struggles against the primary's glare — the components are separated by about 0.4″ at magnitudes near 2.6. The companion is about 8.0 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Graffias — Double Star in Scorpius

HIP 78820; Beta1 Scorpii; 8 Scorpii

Magnitude 2.6^m DoubleStar Scorpius (Sco) Visible

Star Map + List + Plan

About Graffias

Description

Graffias (also called Acrab) is a complex multiple star system at magnitude 2.62 in Scorpius, consisting of at least six stars. The primary is a blue giant of spectral type B1V. Located about 400 light-years from Earth, a small telescope reveals a double star with components separated by about 14 arcseconds.

Observing Tips

Graffias sits at the head of Scorpius, forming a line with Dschubba and Pi Sco. A small telescope splits it into a handsome double — a bright blue-white primary and a fainter companion. Best observed June through August when Scorpius is prominent.

History

The name Graffias comes from Greek/Latin roots meaning 'claws' or 'crab.' The alternate name Acrab comes from the Arabic 'al-'aqrab,' meaning 'the scorpion.' The multiple star nature has been gradually revealed over centuries of observation.

Fun Facts

Graffias is one of the most complex stellar systems visible in a small telescope — what appears as a simple double is actually six stars gravitationally bound together, revealed through spectroscopic and interferometric studies.

Observe

1Physical Properties

Magnitude 2.62

Spectral Type B1V

Star Color Blue (B-V -0.07)

Distance 400 ly

2Position & Identifiers

RA 16h 05m 26.2s

Dec -19° 48' 20.0"

Constellation Scorpius (Sco)

HR 5984

HIP 78820

HD 144217

SAO 159682

Bayer Beta1

Flamsteed 8 Sco

Double Cat 9913

SIMBAD Wikipedia

3How easy to split?

Primary 2.6 mag Companion 10.6 mag Separation 0.4″

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Imp.	Imp.	Imp.
150 mm Newton 150mm Newt.	Imp.	Imp.	Imp.
Celestron C8 (203 mm SCT) C8 203mm	Imp.	Imp.	Imp.

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

Out of reach for typical amateur telescopes, even at Bortle 3.

4Visibility

Set a location in User Settings to see visibility data.

Best season Apr – Jun (peak: May)

5Multiple Star System Quintuple

Components 5 (quintuple)

Component IDs O

Separation 0.4″

Companion Mag 10.6

Companion Sp B2V

Position Angle 224°

Star Colors A: Blue B: Blue

Discoverer BU 947

Notes

CPM with HR 5985 = ADS 9913C, at 14" and with B, 5.9v at 0.5", possibly SB. Lunar occultations and speckle | interferometry indicate companions 4.2v at 0.001" from A and 7.6v at 0.129" from C. Occultations by Jupiter and Io in | 1971 indicate complex system. Component C occulted by Io revealed the 2.5 mag. fainter companion at 0.1".

Separation over time

Period: 220.0 y Eccentricity: 0.685 Now: 0.36", PA 230° + 0.03" in 5 years

Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.

Eyepiece View

Telescope Eyepiece

80x Dawes: 1.9″ TFOV: 0.6°

Seeing

Scale Realistic = true angular size

A: 2.6 · B: 10.6 · Sep: 0.4″ · PA: 224° · N up, E right

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

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Size Comparison

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Spectral Classification

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map

Stellar Lifecycle

Blackbody Spectrum

Stellar Absorption Spectrum

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

Stellar Fusion

Discover

15Stellar Notes

Spectroscopic Binary

ADS 9913AD, 6.8281d, K 129.0k/s, V0 -1.0k/s, msin3i 16.0, asini 11.6. Mag. difference about 1v. Apsidal period | 51000 times orbital. Unresolved by speckle interferometry. Possible third SB component.

Group/Cluster

Sco OB2; Sco-Cen assoc.; probable member of Sco-Cen cluster; upper Sco region.

Spectral

Ca and Na lines nearly stationary.

Dynamical

0.004".

Alternative Names

Graffias; Grafias; Grassias; Acrab; Akrab; Elacrab.

Remarks

From occult. by Jupiter, diam. Beta Sco A1 = 0.000422"; diam. Beta Sco A2 = 0.000264".