Triangulum
A small but neatly drawn triangle of three stars between Andromeda and Aries. Its stars are modest, but its hidden treasure is enormous: the spiral galaxy M33.
Star chart · schematic positions
Drag to pan · dashed rings mark deep-sky objects · east is left
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Tap any labelled star in the chart to read its name, magnitude and spectral type.
Why it matters
Triangulum is one of the 48 constellations listed by Ptolemy and shows how a modest pattern can anchor a major discovery. It points the way to M33, the third-largest galaxy in the Local Group, and its two brightest stars were used in early measurements of the sky.
How to find it tonight
- 1Look east of Andromeda's chain of stars for a small, sharply drawn triangle.
- 2In November evenings Triangulum is high in the south, its apex pointing upward.
- 3M33 sits just outside the triangle's western edge — use a dark sky, averted vision and binoculars.
- 4Because M33 is face-on, its light is spread out; you need dark skies to see it at all.
Brightest stars on the chart
Beta Trianguli (β Trianguli) · Mothallah (α Trianguli) · Gamma Trianguli (γ Trianguli) · Delta Trianguli (δ Trianguli)
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Figures are rounded averages from NASA, ESA and IAU reference data. Star positions on charts are schematic and approximate.