When is the best time to observe Beta Trianguli?

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

Where is Beta Trianguli located in the sky?

Beta Trianguli lies in the constellation Triangulum at right ascension 02h 10m and declination +34° 59′.

What telescope do I need to see Beta Trianguli?

At magnitude 3.0, Beta Trianguli is visible to the naked eye from dark skies, easy in any binoculars.

Beta Trianguli — Star in Triangulum

Magnitude 3.0^m Star Triangulum (Tri) Visible

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About Beta Tri

Description

Beta Trianguli is a white giant of spectral type A5III at magnitude 3.0 in Triangulum. Located about 127 light-years from Earth, it has a surface temperature of about 8,000 K and a luminosity roughly 70 times solar. Despite its Beta designation, it is actually the brightest star in Triangulum, outshining Alpha Tri by a small margin.

Observing Tips

Beta Tri is the brightest star in the small but distinctive triangle of Triangulum, located between Andromeda and Aries. The three main stars form a narrow, elongated triangle that is easy to spot. The famous Triangulum Galaxy (M33) lies about 4 degrees to the west, and Beta Tri serves as a guide star for finding it. Best observed from October through February.

History

Beta Trianguli has no traditional proper name. Triangulum is one of the original 48 Ptolemaic constellations and was known as 'Deltaton' (after the Greek letter delta) to the ancient Greeks due to its triangular shape. The Romans called it 'Sicilia' because they thought it resembled the triangular island of Sicily.

Fun Facts

Beta Tri is one of several cases where the Beta star is brighter than the Alpha star in a constellation — Bayer sometimes assigned letters based on position rather than strict brightness order. The star is a useful guide for finding M33, the Triangulum Galaxy, the third-largest member of the Local Group.