When is the best time to observe Secunda Hyadum?

Secunda Hyadum is best observed from October through December, with peak visibility during November when it transits around midnight in the Northern Hemisphere.

Where is Secunda Hyadum located in the sky?

Secunda Hyadum lies in the constellation Taurus at right ascension 04h 23m and declination +17° 33′.

What telescope do I need to see Secunda Hyadum?

At magnitude 3.8, Secunda Hyadum is visible to the naked eye from dark skies, easy in any binoculars.

Secunda Hyadum — Star in Taurus

HIP 20455; Delta1 Tauri; 61 Tauri

Magnitude 3.8^m Star Taurus (Tau) Visible

Star Map + List + Plan

About Secunda Hyadum

Description

Secunda Hyadum, Delta1 Tauri, is a yellow giant of spectral class G9.5 III about 155 light-years away — another bright Hyades member. It shines at magnitude 3.76 and is very similar in physical properties to Prima Hyadum: about 11 solar radii, 75 solar luminosities, and a member of the 625-million-year-old cluster.

Observing Tips

Secunda Hyadum lies close to Prima Hyadum along the western arm of the Hyades V. The two form an easily located bright pair among the many cluster stars. Binoculars reveal their nearly identical warm yellow-orange colors — a consequence of shared cluster age and similar stellar masses. Best observed November through March.

History

The Latin name means "Second of the Hyades," parallel in formation to Prima Hyadum. The names date from medieval European stellar cataloging.

Fun Facts

Because Secunda Hyadum and Prima Hyadum are both Hyades members at almost identical distances, any apparent brightness difference between them reflects real differences in intrinsic luminosity and evolutionary state — useful for probing how slight mass variations alter late-stage giant-branch evolution.