The Solar Spectrum
27.02.2005

It is still not known why the Sun's light is missing some colors. Shown above are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device.

An Active Sunspot Viewed Sideways
2.04.2007

Why are there dark spots on the sun? Although noted for thousands of years, sunspots have been known for decades to be regions of the Sun that are slightly depressed and cooled by the Sun's complex and changing magnetic field.

Equinox + 1
20.03.2004

Twice a year, at the Spring and Fall equinox, the Sun rises due east. In an emphatic demonstration of this celestial alignment, photographer Joe Orman recorded this inspiring image of the Sun rising exactly along the east-west oriented Western Canal, in Tempe,Arizona, USA.

A Year in Sunsets
21.12.2024

A year in sunsets, from April 2023 to March 2024, track along the western horizon in these stacked panoramic views. The well-planed sequence is constructed of images recorded near the 21st day of the indicated month from the same location overlooking Cairo, Egypt.

A Crescent Sunrise
17.08.1999

Normally, the Moon shows phases, but the Sun does not. The reason is founded in the fact that the Moon shines only by reflected sunlight. When the Moon is closer to the Sun than the Earth, only part of it appears to be lit - resulting in a familiar crescent-shaped phase.

Equinox Plus 1
21.03.2010

Twice a year, at the Spring and Fall equinox, the Sun rises due east. In an emphatic demonstration of this celestial alignment, photographer Joe Orman recorded this inspiring image of the Sun rising exactly along the east-west oriented Western Canal, in Tempe, Arizona, USA.

A Solar Filament Lifts Off
9.08.2000

Hot gas frequently erupts from the Sun. One such eruption produced the glowing filament pictured above, which was captured on July 19 by the Earth-orbiting TRACE satellite. The filament, although small compared...

APOD: 2025 November 17 Б Comet Lemmons Wandering Tail
17.11.2025

What has happened to Comet Lemmon's tail? The answer is blowing in the wind Б the wind from the Sun in this case. This continuous outflow of charged particles from...

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.

Perihelion to Aphelion
8.07.2021

Aphelion for 2021 occurred on July 5th. That's the point in Earth's elliptical orbit when it is farthest from the Sun. Of course, the distance from the Sun doesn't determine the seasons.