The Ghostly Tail of Comet SWAN
6.11.2006

What causes the structure in Comet SWAN's tail? Comet SWAN, which unexpectedly flared up to naked-eye brightness last week, has been showing detail in its ion tail that might be described as ghostly.

Kepler s House in Linz
15.05.2018

Four hundred years ago today (May 15, 1618) Johannes Kepler discovered the simple mathematical rule governing the orbits of the solar system's planets, now recognized as Kepler's Third Law of planetary motion.

Eclipse over Chongqing, China
24.07.2009

The daytime sky grew dark, the temperature dropped, and lights came on as Chongqing, China, was plunged into the Moon's shadow during the July 22nd total solar eclipse. This serene, wide-angle view of the event looks to the east over the large, populous city from a newly constructed park.

Moon Setting Behind Teide Volcano
22.03.2020

These people are not in danger. What is coming down from the left is just the Moon, far in the distance. Luna appears so large here because she is being photographed through a telescopic lens.

A Hale-Bopp Triple Crown
23.07.1997

It was truly a busy sky. In one of the more spectacular photos yet submitted to Astronomy Picture of the Day, Don Cooke of Lyme, New Hampshire caught the Sun, Moon, Earth, night sky, Pleiades star cluster, and Comet Hale-Bopp all in one frame.

Spot The Planet
10.12.1999

OK, it's a picture of the Sun (duh!), but can you spot the planet? Of course, most of the spots you've spotted are sunspots, as large or larger than planet Earth itself.

Genesis Missions Hard Impact
5.07.2009

A flying saucer from outer space crash-landed in the Utah desert in 2004 after being tracked by radar and chased by helicopters. No space aliens were involved, however. The saucer, pictured above, was the Genesis sample return capsule, part of a human-made robot Genesis spaceship launched in 2001 by NASA itself to study the Sun.

Solar Eclipse and SOHO
31.03.2006

Neither rain, nor snow, nor dark of night can keep the space-based SOlar Heliospheric Observatory (SOHO) from watching the Sun. In fact, from its vantage point 150 million kilometers sunward of planet Earth, SOHO's cameras can always monitor the Sun's outer atmosphere, or corona.

Sungrazer
22.03.2009

The Sun destroyed this comet. Arcing toward a fiery fate, this Sungrazer comet was recorded by the SOHO spacecraft's Large Angle Spectrometric COronagraph(LASCO) on 1996 Dec. 23. LASCO uses an occulting disk...

APOD: 2026 August 5 Б Spokes on Saturn's B Ring
5.08.2026

DonБt get spooked by SaturnБs ghostly spokes! Today we feature a nearly two-hour timelapse of Saturn and its rings looping forwards and backwards. A day on Saturn is only 10 hours long, so two hours of observation covers quite a bit of its rotation.