When is the best time to observe Kaus Meridionalis?

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

Where is Kaus Meridionalis located in the sky?

Kaus Meridionalis lies in the constellation Sagittarius at right ascension 18h 21m and declination -29° 50′.

What telescope do I need to split Kaus Meridionalis?

Splitting Kaus Meridionalis requires an aperture of roughly 60 mm or larger — the components are separated by about 59.9″ at magnitudes near 2.7. The companion is about 9.2 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Kaus Meridionalis — Double Star in Sagittarius

HIP 89931; Delta Sagittarii; 19 Sagittarii

DoubleStar Sagittarius (Sgr) Visible

Star Map + List + Plan

About Kaus Meridionalis

Description

Kaus Meridionalis is an orange giant of spectral type K3IIIa at magnitude 2.70 in Sagittarius. Located about 306 light-years from Earth, it has a luminosity of roughly 1,180 times solar. It marks the middle of the Archer's bow in the traditional constellation figure and forms part of the Teapot asterism.

Observing Tips

Kaus Meridionalis forms the right side of the Teapot's body in Sagittarius, between Kaus Australis below and Kaus Borealis above — the three 'Kaus' stars trace the bow. Its warm orange color helps distinguish it from the bluer neighboring stars. Best observed July through September.

History

The name Kaus Meridionalis means 'the middle (part of the) bow,' combining Arabic 'qaws' (bow) with Latin 'meridionalis' (middle). The three Kaus stars have been associated with the Archer's bow since ancient Babylonian times.

Fun Facts

The three Kaus stars — Australis, Meridionalis, and Borealis — form one of the few groups of bright stars named systematically with Latin directional suffixes appended to an Arabic root word, reflecting the blend of Arabic and European astronomical traditions.

Observe

1Physical Properties

Magnitude 2.70

Spectral Type K2.5IIIa CN0.5

Star Color Red (B-V 1.38)

Distance 348 ly

2Position & Identifiers

RA 18h 20m 59.7s

Dec -29° 49' 41.0"

Constellation Sagittarius (Sgr)

HR 6859

HIP 89931

HD 168454

Bayer Delta

Flamsteed 19 Sgr

Double Cat 11264

SIMBAD Wikipedia

3How easy to split?

Primary 2.7 mag Companion 11.9 mag Separation 59.9″

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard	V. hard+	V. hard
150 mm Newton 150mm Newt.	Medium	Hard+	Hard
Celestron C8 (203 mm SCT) C8 203mm	Medium+	Medium	Hard+

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 May – Jul (peak: Jun)

5Multiple Star System Quadruple

Components 4 (quadruple)

Component IDs AD

Separation 59.9″

Companion Mag 11.9

Position Angle 225°

Star Colors A: Red

Discoverer SEE 350

Separation over time

Measured 1896 → 1999 (103 y)

Separation drift 58.1" → 59.9" (+1.80")

Rate +0.0175" / y

PA drift 221° → 225° (+4°, +0.039°/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.