Suspension Bridge Solargraph
15.01.2009

If every picture tells a story, this one might make a novel. The six month long exposure compresses the time from December 17, 2007 to June 21, 2008 into a single point of view.

Retrograde Mars
27.10.2014

Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun.

APOD: 2024 December 4 Б Driveway Analemma
4.12.2024

Does the Sun return to the same spot on the sky every day?б No.б A more visual answer is an analemma, a composite of sky images taken at the same time and from the same place over a year.

Small Star
20.11.1999

A dim double star system cataloged as Gliese 623 lies 25 light-years from Earth, in the constellation of Hercules. The individual stars of this binary system were distinguished for the first time when the Hubble Space Telescope's Faint Object Camera recorded this image in June 1994.

Retrograde Mars
16.12.2003

Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun.

Space Station Silhouette on the Moon
2.04.2019

What's that unusual spot on the Moon? It's the International Space Station. Using precise timing, the Earth-orbiting space platform was photographed in front of a partially lit gibbous Moon last month. The featured image was taken from Palo Alto, California, USA with an exposure time of only 1/667 of a second.

The Black Hole in the Milky Way
2.11.2012

At the center of our Milky Way Galaxy, a mere 27,000 light-years away, lies a black hole with 4 million times the mass of the Sun. Fondly known as Sagittarius A* (pronounced A-star)...

A Double Eclipse of the Sun
21.03.2015

Can the Sun be eclipsed twice at the same time? Last Friday was noteworthy because part of the Earth was treated to a rare total eclipse of the Sun. But also on Friday, from...

Solstice Illuminated: A Year of Sky
22.12.2015

Can you find which day is the winter solstice? Each panel shows one day. With 360 movie panels, the sky over (almost) an entire year is shown in time lapse format as recorded by a video camera on the roof of the Exploratorium museum in San Francisco, California.

ISS Transits Mars
23.09.2020

Yes, but have you ever seen the space station do this? If you know when and where to look, watching the bright International Space Station (ISS) drift across your night sky is a fascinating sight -- but not very unusual.