When is the best time to observe Asellus Australis?

Asellus Australis is best observed from December through February, with peak visibility during January when it transits around midnight in the Northern Hemisphere.

Where is Asellus Australis located in the sky?

Asellus Australis lies in the constellation Cancer at right ascension 08h 45m and declination +18° 09′.

What telescope do I need to see Asellus Australis?

At magnitude 3.9, Asellus Australis is visible to the naked eye from dark skies, easy in any binoculars.

Asellus Australis — Star in Cancer

HIP 42911; Delta Cancri; 47 Cancri

Magnitude 3.9^m Star Cancer (Cnc) Visible

Star Map + List + Plan

About Asellus Australis

Description

Asellus Australis, Delta Cancri, is a G-type giant of spectral class G9 III about 130 light-years away. At magnitude 3.94 it is a modest but easy naked-eye object in Cancer, close to the famous open cluster M44 (the Beehive Cluster). Asellus Australis marks the southern "donkey" of classical mythology, paired with Asellus Borealis (Gamma Cnc) to the north.

Observing Tips

Asellus Australis sits just south of the Beehive Cluster (M44, also called Praesepe), separated by only about 1 degree. Any sweep of this area with binoculars reveals the cluster's stars filling the field while the two Aselli flank it as bright orange anchors. Best observed January through May.

History

The name is Latin for "southern donkey." In Greek mythology, the two Aselli (Boreal and Austral) were the donkeys that carried the gods Dionysus and Hephaestus during the Olympian war against the Titans — they were placed in the sky beside the manger (Praesepe, the Latin name for M44).

Fun Facts

The two Aselli plus the Beehive Cluster form one of the most culturally-rich celestial groupings in the traditional Western sky: the stars are the donkeys, and the manger they feed from is the star cluster. This mythological pairing was already noted by Theophrastus in the 4th century BC as a weather-predicting asterism.