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Larry Sessions

Larry Sessions

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.

A celestial cloud of swirling gases.

See Messier 8, the Lagoon Nebula

Posted by in Astronomy Essentials | Clusters Nebulae Galaxies | 3 days ago
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The Lagoon – aka M8 – is the largest and brightest nebula, or cloud in space, in the vicinity of the Teapot asterism in the constellation Sagittarius.

61 Cygni is the Flying Star

Posted by in Astronomy Essentials | Brightest Stars | 2 weeks ago
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Although it’s not bright, 61 Cygni moves exceptionally rapidly against the background of more distant stars. Its motion reveals its nearness to Earth.

Antares is the Heart of the Scorpion

Posted by in Astronomy Essentials | Brightest Stars | Favorite Star Patterns | 1 month ago
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Bright red Antares is easy to spot now. It’s the brightest star in the constellation Scorpius and represents the Scorpion’s Heart.
Photo of blue-white star Spica.

Spica is a whirling double star

Posted by and in Astronomy Essentials | Brightest Stars | 3 months ago
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Spica’s 2 stars orbit a common center of gravity in only 4 days. Their mutual gravity distorts each star into an egg shape, with the pointed ends facing each other.
What appears to be a densely populated star field with a few galaxies visible.

The Coma Cluster of galaxies

Posted by in Clusters Nebulae Galaxies | 4 months ago
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The Coma Cluster is one of the richest galaxy clusters known. How many suns and how many worlds might be located in this direction of space?

Observatory dome in foreground, Milky Way in background, and Alpha Centauri's position marked.

Alpha Centauri, star system closest to our sun

Posted by in Astronomy Essentials | Brightest Stars | 4 months ago
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We see this nearly star system as a single star in our sky, but it’s really 3 stars. Of the 3, Proxima is closer to our sun than any other known star.

Alpha and Beta Centauri, pointing to Crux.

Beta Centauri is a Southern Pointer Star

Posted by in Astronomy Essentials | Brightest Stars | 4 months ago
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Beta Centauri – aka Hadar – joins Alpha Centauri in pointing to the Southern Cross. Like Alpha, Beta Centauri is also 3 stars, but 2 of Beta’s stars will someday become nearby supernovae.
Chart showing moon, Castor, Pollux, Procyon on April 12, 2019.

Moon and Gemini stars on April 12

Posted by in Tonight | 4 months ago
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Watch for Gemini’s 2 brightest stars – Castor and Pollux – near tonight’s moon. On the other side of the moon, you’ll see a 3rd bright star. It’s Procyon in the constellation Canis Minor, the Lesser Dog.

Leo loses his tail. We gain a constellation

Posted by in Tonight | 5 months ago
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The constellation Leo once had a tail, a clump of faint stars. Now these same stars are known as Coma Berenices, the hair of a queen.

Acrux, brightest star in Southern Cross

Posted by in Brightest Stars | 5 months ago
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You have to go far south on Earth’s globe to see the Southern Cross. Bluish Acrux, aka Alpha Crucis, is its brightest star.