Mercury Crosses a Quiet Sun
2.12.2019

What's that black dot crossing the Sun? The planet Mercury. Mercury usually passes over or under the Sun, as seen from Earth, but last month the Solar System's innermost planet appeared to go just about straight across the middle.

Mercury Transits the Sun
13.05.2003

How big is the Sun? The Sun is not only larger than any planet, it is larger than all of the planets put together. The Sun accounts for about 99.9 percent of all the mass in its Solar System.

Leaning Tower, Active Sun
1.04.2022

The natural filter of a hazy atmosphere offered this recognizable architecture and sunset view on March 27. Dark against the solar disk, large sunspots in solar active regions 2975 and 2976 are wedged between the Duomo of Pisa and its famous Leaning Tower.

APOD: 2024 January 14 Б Dragon Aurora over Iceland
14.01.2024

Have you ever seen a dragon in the sky? Although real flying dragons don't exist, a huge dragon-shaped aurora developed in the sky over Iceland in 2019. The aurora was caused...

The Suns Surface in 3D
24.06.2003

How smooth is the Sun? The new Swedish 1-m Solar Telescope, deployed in the Canary Islands only last year, allows imaging of objects less than 100-km across on the Sun's surface. When pointed toward the Sun's edge, surface objects now begin to block each other, indicating true three-dimensional information.

Perihelion Sun 2023
14.01.2023

Perihelion for 2023, Earth's closest approach to the Sun, was on January 4 at 16:17 UTC. That was less than 24 hours after this sharp image of the Sun's disk was recorded with telescope and H-alpha filter from Sidney, Australia, planet Earth.

Bakasa Eclipse Sequence
6.07.2001

Starting at the upper left, this sequence of images follows the progress of the magnificent 21 June, 2001 solar eclipse in the clear skies over Bakasa, Zimbabwe. These pictures were recorded using a small reflecting telescope and digital camera with the approximate local time given above each frame.

A Giant Starspot on HD 12545
2.11.2003

What could cause a star to have such a large spot? Our Sun itself frequently has sunspots, relatively cool dark magnetic depressions that move across its surface. HD 12545, however, exhibits the largest starspots yet observed.

Aurora Alaskan Style
29.03.2001

Have you checked the space weather report lately? With a coronal mass ejection (CME) headed our way and an immense sunspot group tracking across the solar photosphere, skygazers should be on the alert.

Station and Shuttle Transit the Sun
23.05.2010

That's no sunspot. On the upper right of the above image of the Sun, the dark patches are actually the International Space Station (ISS) and the Space Shuttle Atlantis on mission STS-132.