Larry Sessions has written many favorite posts in EarthSky's Tonight area. He's a former planetarium director in Little Rock, Fort Worth and Denver and an adjunct faculty member at Metropolitan State University of Denver. He's a longtime member of NASA's Solar System Ambassadors program. His articles have appeared in numerous publications including Space.com, Sky & Telescope, Astronomy and Rolling Stone. His small book on world star lore, Constellations, was published by Running Press.
Achernar is the 9th brightest star and flattest star known. It’s famous as the southernmost bright star in the constellation Eridanus the River. Here’s why much of Earth never sees it … and how you can.
Altair is only 16.8 light-years from Earth, making it one of our closest stellar neighbors. At least 2 features of the star make it distinctive. For one thing, Altair needs only 10 hours to spin once on its axis, in contrast to roughly a month for our sun.