When is the best time to observe Megrez?

Megrez is best observed from February through April, with peak visibility during March when it transits around midnight in the Northern Hemisphere.

Where is Megrez located in the sky?

Megrez lies in the constellation Orsa Maggiore at right ascension 12h 15m and declination +57° 02′.

What telescope do I need to see Megrez?

At magnitude 3.3, Megrez is visible to the naked eye from dark skies, easy in any binoculars.

Megrez — Stella in Orsa Maggiore

Delta UMa

Magnitudine 3.3^m Star Orsa Maggiore (UMa) Visibile

Mappa stellare + Lista + Piano

Su Megrez

Descrizione

Megrez, Delta Ursae Majoris, is an A-type main-sequence star about 80 light-years away and the faintest of the seven stars of the Big Dipper. It marks the junction where the Dipper's "handle" meets its "bowl." Megrez is about 1.6 times the Sun's mass, twice the radius, and 14 times the luminosity. It is also a suspected debris-disk star, with mid-infrared excess suggesting a surrounding ring of dust.

Consigli per l'osservazione

Megrez's relative faintness (magnitude 3.31) is a classic sky-quality check — if you can see Megrez clearly with the naked eye, you have a reasonably dark site. From light-polluted suburban skies, the Big Dipper looks "incomplete" because Megrez disappears first. Use a pair of binoculars to confirm its white color and position at the corner of the Dipper's bowl, at the base of the handle. Circumpolar from all of the northern hemisphere.

Storia

The name Megrez comes from the Arabic "al-maghriz," meaning "the root of the tail" — referring to the tail-root of the great bear. All seven Dipper stars carry Arabic-derived names. Megrez's relatively modest brightness puzzled pre-modern astronomers; some ancient records refer to it being "fainter than expected," possibly due to observer uncertainty about the star's real appearance.

Curiosità

Megrez is part of the Ursa Major Moving Group, a loose cluster of stars that share a common origin and are drifting through the galaxy together — including most of the other Big Dipper stars (all except Dubhe and Alkaid). The group is about 300 million years old. Megrez is one of the youngest prominent stars in the northern sky; on cosmic timescales it will remain a normal hydrogen-fusing dwarf for another billion years.