Saturn: 1993 2022
19.08.2022

Saturn is the most distant planet of the Solar System easily visible to the unaided eye. With this extraordinary, long-term astro-imaging project begun in 1993, you can follow the ringed gas giant for one Saturn year as it wanders once around the ecliptic plane, finishing a single orbit around the Sun by 2022.

Julius Caesar and Leap Days
29.02.2000

Even as leap days go, today is a remarkable one. In 46 BC, Julius Caesar, pictured above in a self-decreed minted coin, created a calendar system that added one leap day every four years.

The Averted Side Of The Moon
21.10.2000

This vintage 60-kopek stamp celebrates a dramatic achievement. On the 7th of October, 1959 (7/X/1959), the Soviet interplanetary station which has come to be called "Luna 3" successfully photographed the far side of the moon giving denizens of planet Earth their first ever view of this hidden hemisphere.

Apogee Moon, Perigee Moon
21.10.2004

Why don't these pieces fit? This third quarter Moon (left) and first quarter Moon were both photographed during the last lunar cycle or lunation with the same telescope and camera. But, simply combining the pictures into one sharp, full surface view would clearly be a problem.

Sun Block
18.08.1999

During a total solar eclipse, Earth's moon blocks the sun - almost exactly. While the sun is about 400 times wider than the moon, it is also about 400 times farther away and each appears to be half a degree or so in diameter.

Moonrise Through Mauna Keas Shadow
5.12.2010

How can the Moon rise through a mountain? It cannot -- what was photographed here is a moonrise through the shadow of a large volcano. The volcano is Mauna Kea, Hawai'i, USA, a frequent spot for spectacular photographs since it is arguably the premier observing location on planet Earth.

Miass River Sunrise
2.03.2013

Each day on planet Earth can have a serene beginning at sunrise as the sky gently grows bright over a golden eastern horizon. This sunrise panorama seems to show such a moment on the winter morning of February 15.

Moonrise and Mountain Shadow
14.03.2020

What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is 3.14 radians (aka 180 degrees) from the Sun in ecliptic longitude.

Parker vs Perseid
16.08.2018

The brief flash of a bright Perseid meteor streaks across the upper right in this composited series of exposures made early Sunday morning near the peak of the annual Perseid meteor shower.

Heating Coronal Loops
14.08.2005

Why is the corona of the Sun so hot? Extending above the photosphere or visible surface of the Sun, the faint, tenuous solar corona can't be easily seen from Earth, but it is measured to be hundreds of times hotter than the photosphere itself.