Astronomers use many methods to determine this number, including gravitational lensing, the universe’s expansion rate, and more.

September’s Full Corn Moon is eclipsed for some observers, Titan passes behind Saturn, and Mars moves north of Spica in the ...

Saturn’s largest moon, Titan, transits with its shadow early this morning, passing over the planet’s northern polar region.

The Red Planet’s mantle is giving scientists clues to its geological history.

Today in the history of astronomy, NASA announces evidence of material being consumed by the black hole at the center of our ...

Ice giant Uranus is in Taurus, floating near the Pleiades star cluster and easy to locate in the early-morning sky.

Planetariums around the world are invited to participate in this year’s edition of the IAU’s annual outreach event.

John Dobson, born in 1915, relocated to San Francisco from Beijing in 1927. Following a period as a monk within the Ramakrishna Order (1944-1967), Dobson cultivated a passion for astronomy. He is ...

Mars and Spica will appear in close proximity (2° separation) in the evening western sky shortly after sunset, setting before 9 PM local daylight time. Observations of Mars and Spica are best ...

Equuleus, also known as the Foal, is a small and faint constellation located southwest of Pegasus. Unlike many constellations, Equuleus lacks bright stars, nearby stars, prominent meteor showers, or ...

On August 8th, the close conjunction of the Moon and Pluto will occur, though Pluto's visibility will be obscured by the Moon's brightness. Observation of the double star Albireo in Cygnus is ...

Saturn, at magnitude 0.6 in Pisces, is observable in the southeast at approximately 30° altitude. Titan, Saturn's largest moon, undergoes an occultation behind Saturn, beginning around 11:10 P.M. EDT ...