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Achernar, the star at the southern end of the River

If you have a very dark sky on these January evenings - and if you're at the extreme southern U.S. or farther south - you can see Achernar, the star that marks the end of the River, aka the constellation Eridanus.

Tonight for January 13, 2015

If you live at a mid-northern latitude, you can see only a portion of the constellation Eridanus. Notice on this chart that the star Achernar doesn’t appear. Via AlltheSky

Achernar is the flattest star known. Read more about Achernar here.

The chart above is almost just like the January 11 chart. But we’ve changed our observing location. Normally, our charts are set for the geographical center of the continental U.S. – say, the latitude of Wichita, Kansas (about 37o north latitude). The chart above is set to the extreme southern U.S. or similar latitudes around the world.

It’s as if we’re gazing at stars from this southerly latitude in the Northern Hemisphere . . . maybe along the Texas/Mexico border, or from the Florida Keys, or from the latitude of some great cities around the world including Miami in the U.S., Taipei in China, Abu Dhabi in the United Arab Emirates, or Muscat in Oman. From the latitude of these cities (about 25 degrees N.), the bottom part of constellation Eridanus the River may be seen just above the southern horizon. It’s from this latitude, or farther south on Earth’s globe, that you can see the famous star that marks the end of the River. The star is called Achernar.

Achernar – the star marking the end of the celestial River Eridanus – is very bright. But, bright or not, you’ll never see it anywhere but right next to the southern horizon if you’re observing from the extreme southern U.S., or a similar latitude. And you won’t see it at all from a more northerly latitude. That’s because this star is located very far to the south on the celestial sphere, the imaginary dome of stars surrounding Earth.

Find Achernar’s rising and setting time in your sky

Achernar makes only a tiny arc above the southern horizon from the southern U.S., so you have to be looking at just the right time to see it – for example, at nightfall and early evening tonight. Achernar – if you see it, you’ll never forget it!

Bottom line: On Monday morning – January 27, 2014 – you’ll find the moon as a waning crescent in the east before dawn. The bright reddish star next to Monday morning’s moon is Antares, Heart of the Scorpion in the constellation Scorpius. The bow of the waning moon points downward toward Venus, which is visible in the east shortly before dawn. In the late January evening sky – if you’re in the extreme southern U.S., or farther south – you can see the star Achernar, the end of the River in the constellation Eridanus.

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