When is the best time to observe Fulu?

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

Where is Fulu located in the sky?

Fulu lies in the constellation Cassiopeia at right ascension 00h 37m and declination +53° 54′.

What telescope do I need to see Fulu?

At magnitude 3.7, Fulu is visible to the naked eye from dark skies, easy in any binoculars.

Fulu — Star in Cassiopeia

HIP 2920; Zeta Cassiopeiae; 17 Cassiopeiae

Magnitude 3.7^m Star Cassiopeia (Cas) Visible

Star Map + List + Plan

About Fulu

Description

Fulu, Zeta Cassiopeiae, is a B-type subgiant of spectral class B2 IV about 592 light-years away. At magnitude 3.66 it is a prominent member of Cassiopeia's "W" pattern, though not among the five figure-defining stars. Fulu is a classical slowly pulsating B-type (SPB) variable star, with extremely small-amplitude brightness variations of a few thousandths of a magnitude.

Observing Tips

Fulu sits near the southeastern edge of Cassiopeia. The tiny pulsational variability is not detectable with amateur equipment; Fulu appears visually steady. Binoculars show its crisp blue-white color. Circumpolar from mid-northern latitudes.

History

The IAU adopted the name "Fulu" in 2017 — a Chinese-origin name meaning "auxiliary road" or "assistant bureaucrat," reflecting this star's role in the Chinese celestial administration. In that tradition, stars around Cassiopeia represent palace officials arranged in hierarchical order.

Fun Facts

SPB variables like Fulu pulsate in non-radial modes — the surface oscillates in patterns that produce the characteristic low-amplitude variability. These pulsations are probing the deep interior structure of massive young stars, a field called asteroseismology that has blossomed with missions like Kepler and TESS.