Home > Constellations, Ephemeris Program, Mythology, Observing > Ephemeris: 02/25/2025 – Eridanus, a river in the sky

Ephemeris: 02/25/2025 – Eridanus, a river in the sky

February 25, 2025

This is Ephemeris for Tuesday, February 25th. Today the Sun will be up for 10 hours and 59 minutes, setting at 6:25, and it will rise tomorrow at 7:24. The Moon, 2 days before new, will rise at 7:00 tomorrow morning.

One of the more obscure constellations around is Eridanus, which depicts a river. At 8 PM the river starts near the lower right corner of Orion, near the bright star Rigel and flows to the lower right then zigzags back down to the south-southwestern horizon, it then heads below the horizon. One has to travel to the far south to see the southern terminus of the river, the bright star Achernar. Writers over the ages have seen here the Nile and the Earth circling river Ocean of the ancient flat earth days. Achernar is actually two stars, the brightest was discovered to be the flattest star known, due to its rapid spin. The dimensions of Achernar A has been determined to be twice as wide across its equator than from pole to pole. It’s 139 light years away.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.

Addendum

An animated GIF image of the constellation Eridanus
An animated GIF image of the constellation Eridanus the river, as seen tonight, February 25 2025, at 8 PM from Northern Michigan. It also showing the parts of Eridanus that are below the horizon for us, down to the star Achernar at the southern end. Created using Stellarium and GIMP.
Categories: Constellations, Ephemeris Program, Mythology, Observing