Mercury and Venus Over Paris
12.04.2010

Go outside tonight and see one of the more interesting planetary conjunctions of recent years. Just after sunset, the planets Mercury and Venus are visible quite near each other. Now Venus, being commonly discernible as one of the brightest objects in the sky, is frequently mistaken for an airplane.

A Full Sky Aurora Over Norway
3.01.2012

Higher than the highest building, higher than the highest mountain, higher than the highest airplane, lies the realm of the aurora. Auroras rarely reach below 60 kilometers, and can range up to 1000 kilometers. Aurora light results from energetic electrons and protons striking molecules in the Earth's atmosphere.

APOD: 2024 July 9 Б Noctilucent Clouds over Florida
9.07.2024

These clouds are doubly unusual. First, they are rare noctilucent clouds, meaning that they are visible at night -- but only just before sunrise or just after sunset. Second, the source of these noctilucent clouds is actually known.

The Gegenschein
26.12.2006

If you look carefully enough, you can even see the glow of the Sun in the opposite direction. At night this glow is known as the gegenschein (German for "counter glow"), and can be seen as a faint glow in an extremely dark sky. The gegenschein is sunlight back-scattered off small interplanetary dust particles.

Just Passing Through
25.08.2007

M33 is a big, beautiful spiral galaxy a mere 3 million light-years away, understandably a popular target for enthusiastic astro-imagers. Just as understandably, interfering satellite trails and airplane streaks that are becoming more common in planet Earth's busy night sky are processed out of their finished images.

Atlas V Launches MMS
22.03.2015

Birds don't fly this high. Airplanes don't go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description.

Endeavour to Orbit
16.03.2008

Birds don't fly as high. Airplanes don't go as fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description.

Iridescent Cloud Edge Over Colorado
28.10.2014

Sometimes your eclipse viewing goes bad in an interesting way. While watching and photographing last Thursday's partial solar eclipse, a popular astronomy blogger suffered through long periods of clouds blocking the Sun. Unexpectedly, however, a nearby cloud began to show a rare effect: iridescence.

APOD: 2023 November 12 Б Gibbous Moon beyond Swedish Mountain
12.11.2023

This is a gibbous Moon. More Earthlings are familiar with a full moon, when the entire face of Luna is lit by the Sun, and a crescent moon, when only a sliver of the Moon's face is lit.

The Giant and the Glory
6.08.2004

On a flight from Vienna to Brussels, astronomer Franz Kerschbaum looked out the window and photographed this beautiful atmospheric phenomenon, the glory, shining in the direction directly opposite the Sun. Before airplanes, the glory, known to some as the heiligenschein or the Specter of the Brocken, was occasionally seen from mountaintops.