The Belt of Venus over the Valley of the Moon
23.07.2006

Although you've surely seen it, you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly off-color, slightly pink.

Noctilucent Clouds Over Sweden
28.10.2007

Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above.

A Triangular Shadow of a Large Volcano
5.07.2011

Why does the shadow of this volcano look like a triangle? The Mount Teide volcano itself does not have the strictly pyramidal shape that its geometric shadow might suggest. The triangle shadow phenomena is not unique to the Mt. Teide, though, and is commonly seen from the tops of other large mountains and volcanoes.

A Triangular Shadow of a Large Volcano
9.06.2019

Why does the shadow of this volcano look like a triangle? The Mount Teide volcano itself does not have the strictly pyramidal shape that its geometric shadow might suggest. The triangle shadow phenomena is not unique to the Mt. Teide, though, and is commonly seen from the tops of other large mountains and volcanoes.

APOD: 2025 January 15 Б Wolf Moon Engulfs Mars
15.01.2025

Does the Moon ever engulf Mars? Yes, but only in the sense that it moves in front, which happens on rare occasions. This happened just yesterday, though, as seen from some locations in North America and western Africa.

Mars near Opposition
11.04.2014

Tonight Mars is between opposition (April 8) and closest approach (April 14) looping through the constellation Virgo opposite the Sun in the night sky. That makes it prime season for telescopic views of the the Red Planet, like this one from April 3rd.

LDN 988 and Friends
24.09.2015

Stars are forming in dark, dusty molecular cloud LDN 988. Seen near picture center some 2,000 light-years distant, LDN 988 and other nearby dark nebulae were cataloged by Beverly T. Lynds in 1962 using Palomar Observatory Sky Survey plates.

The Protostars within Lynds 483
13.03.2025

Two protostars are hidden in a single pixel near the center of a striking hourglass-shaped nebula in this near-infrared image from the James Webb Space Telescope. The actively forming star system lies in a dusty molecular cloud cataloged as Lynds 483, some 650 light-years distant toward the constellation Serpens Cauda.

Saturn Behind the Moon
14.08.2019

What's that next to the Moon? Saturn. In its monthly trip around the Earth -- and hence Earth's sky -- our Moon passed nearly in front of Sun-orbiting Saturn earlier this week. Actually the Moon passed directly in front of Saturn from the viewpoints of a wide swath of Earth's Southern Hemisphere.

APOD: 2023 May 9 Б Shadows of Earth
9.05.2023

Can you find two Earth shadows in today's image? It's a bit tricky. To find the first shadow, observe that the top part of the atmosphere appears pink and the lower part appears blue. This is because the top half is exposed to direct sunlight, while the lower part is not.