Mammatus Clouds over Saskatchewan
11.08.2021

When do cloud bottoms appear like bubbles? Normally, cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms.

Castle and Meteor by Moonlight
13.08.2011

Each August, as planet Earth swings through dust trailing along the orbit of periodic comet Swift-Tuttle, skygazers enjoy the Perseid Meteor Shower. As Earth moves through the denser part of the comet's wide...

Leonids Above Torre de la Guaita
26.11.2000

Last year, the 1999 Leonids Meteor Shower came to a tremendous crescendo. Observers in Europe observed a sharp peak in the number of meteors visible around 0210 UTC during the early morning hours of November 18. Meteor counts then exceeded 1000 per hour - the minimum needed to define a true meteor storm.

Leonids Above Torre de la Guaita
14.11.2004

The 1999 Leonids Meteor Shower came to an impressive crescendo. Observers in Europe observed a sharp peak in the number of meteors visible around 0210 UTC during the early morning hours of November 18. Meteor counts then exceeded 1000 per hour - the minimum needed to define a true meteor storm.

Highlights of the Winter Sky
12.12.2017

What's up in the sky this winter? The featured graphic gives a few highlights for Earth's northern hemisphere. Viewed as a clock face centered at the bottom, early winter sky events fan out toward the left, while late winter events are projected toward the right.

The Eagle Rises
10.08.2008

Get out your red/blue glasses and check out this remarkable stereo view from lunar orbit. Created from two photographs (AS11-44-6633, AS11-44-6634) taken by astronaut Michael Collins during the 1969 Apollo 11 mission, the 3D anaglyph features the lunar module ascent stage, dubbed The Eagle, as it rises to meet the command module in lunar orbit.

Meteors, Planes, and a Galaxy over Bryce Canyon
6.05.2018

Sometimes land and sky are both busy and beautiful. The landscape pictured in the foreground encompasses Bryce Canyon in Utah, USA, famous for its many interesting rock structures eroded over millions of years.

Leonids from the Road
26.11.2001

Sometimes you just have to stop and watch the meteors. In the early morning hours of November 18, a band of eleven people searched for a flat and cloudless site to see the 2001 Leonids Meteor Shower.

Ghirigori Star Scribbles
12.08.2023

It's fun to scribble on the canvas of the sky. You can use a creative photographic technique to cause the light of point-like stars to dance across a digital image by tapping lightly on the telescope while making an exposure.

APOD: 2020 August 15 Б Mars at the Moons Edge
15.08.2020

Does the Moon ever block out Mars? Yes, the Moon occasionally moves in front of all of the Solar System's planets. Just this past Sunday, as visible from some locations in South America, a waning gibbous Moon eclipsed Mars.