Articles by Geoff Gaherty, Starry Night Sky Columnist

Geoff Gaherty was Space.com's Night Sky columnist and in partnership with Starry Night software and a dedicated amateur astronomer who sought to share the wonders of the night sky with the world. Based in Canada, Geoff studied mathematics and physics at McGill University and earned a Ph.D. in anthropology from the University of Toronto, all while pursuing a passion for the night sky and serving as an astronomy communicator. He credited a partial solar eclipse observed in 1946 (at age 5) and his 1957 sighting of the Comet Arend-Roland as a teenager for sparking his interest in amateur astronomy. In 2008, Geoff won the Chant Medal from the Royal Astronomical Society of Canada, an award given to a Canadian amateur astronomer in recognition of their lifetime achievements. Sadly, Geoff passed away July 7, 2016 due to complications from a kidney transplant, but his legacy continues at Starry Night.

Articles by: Geoff Gaherty

Observing the Evening Sky in Summer's Twilight Zone

By Geoff Gaherty last updated 17 May 22

What is twilight? Scientists have specific definitions for three types of twilight, and many people in the U.S. and Canada live in twilight through much of the summer.

Libra constellation with Saturn and Mars

Saturn at Opposition: See the Ringed Planet at Its Best This Friday

By Geoff Gaherty published 1 June 16

This Friday, June 3, Saturn reaches opposition to the sun. Directly opposite the sun in the sky, Saturn rises as the sun sets and sets as the sun rises, remaining visible all night.

Mars Makes Closest Approach to Earth in 11 Years on May 30

By Geoff Gaherty published 25 May 16

On May 30, Mars will come within 46.8 million miles (75.3 million kilometers) of Earth — closer than the Red Planet has been since 2005. Here's what to expect.

On Sunday morning (May 22) at 7 a.m. EDT, Mars reaches opposition with the sun.

Mars at Opposition: See the Red Planet with Your Own Eyes This Weekend

By Geoff Gaherty published 20 May 16

What Lunar Luck! Friday the 13th Is Prime Moon Viewing Time

By Geoff Gaherty published 13 May 16

When is the best time to look at the moon? Check out the first and last quarter for a vivid view.

This NASA graphic depicts the time and location of Mercury as it crosses the face of the sun during the May 9, 2016 Transit of Mercury event.

Mercury Transit of the Sun on May 9: How to See It and What to Expect

By Geoff Gaherty last updated 28 October 19

On Monday (May 9), you will have an opportunity to witness one of the rarest astronomical events: a transit of Mercury across the face of the sun. Here's what to expect.

Best Night Sky Events of May 2016 (Stargazing Maps)

By Geoff Gaherty published 2 May 16

See what's up in the night sky for May 2016, including stargazing events and the moon's phases, in this Space.com gallery courtesy of Starry Night Software.

Spot Big Asteroid Juno in the Night Sky

By Geoff Gaherty published 27 April 16

See Mars, Saturn and Giant Star Shine Together Tonight

By Geoff Gaherty published 24 April 16

The Best Time to See Mercury in 2016 Is Now

By Geoff Gaherty published 15 April 16

Are You Ready for the Transit of Mercury? Rare Event Occurs in May

By Geoff Gaherty published 6 April 16

Start preparing now for one of the major astronomical events of 2016: On May 9, Mercury will pass across the face of the sun.

Moon, Saturn, Mars, and Antares in group, April 2016

Best Night Sky Events of April 2016 (Stargazing Maps)

By Geoff Gaherty published 1 April 16

See what's up in the night sky for April 2016, including stargazing events and the moon's phases, in this Space.com gallery courtesy of Starry Night Software.

The Moon's 'Blue' Last Quarter Phase Explained

By Geoff Gaherty published 31 March 16

See Mars and Saturn Rise Before the Sun

By Geoff Gaherty published 23 March 16

Spring Is Here! Check Out the Equinox's Quirky Math

By Geoff Gaherty published 16 March 16

Spotting the Shadows of Jupiter's Galilean Moons

By Geoff Gaherty published 11 March 16

Jupiter's Return: The Mighty Planet Reaches Opposition on March 8

By Geoff Gaherty published 4 March 16

Best Night Sky Events of March 2016 (Stargazing Maps)

By Geoff Gaherty published 1 March 16

See what's up in the night sky for March 2016, including stargazing events and the moon's phases, in this Space.com gallery courtesy of Starry Night Software.

Zodiacal Light: How to See the Mysterious Glow

By Geoff Gaherty published 24 February 16

Here's how to spot the faint zodiacal light, the mysterious glow caused by millions of particles left over from the solar system's formation.

High in the Sky: How to Spot 'Circumpolar' Constellations

By Geoff Gaherty published 17 February 16

Here's how to see the circumpolar constellations, such as the Great Bear, which are always with us.

February's Last-Quarter Moon: Why It's Missing

By Geoff Gaherty published 10 February 16

As you gaze at the first-quarter moon this week, you may wonder when the last-quarter moon will occur this month. But there won't be one, if you live in North or South America.

Crescent Moon Joins Predawn 'Planet Parade' Thursday

By Geoff Gaherty published 3 February 16

Aldebaran occulted by Moon, February 2016

Best Night Sky Events of February 2016 (Stargazing Maps)

By Geoff Gaherty published 1 February 16

See what's up in the night sky for February 2016, including stargazing events and the moon's phases, in this Space.com gallery courtesy of Starry Night Software.

See Jupiter Shine with the Moon Tonight

By Geoff Gaherty published 27 January 16

Orion the Hunter: Spot Beloved Constellation Overhead Now

By Geoff Gaherty published 21 January 16

Step outside on any evening this month and look toward the south. You will see one of the best-loved constellations, Orion the Hunter, surrounded by a circle of six brilliant stars.

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