Interstellar Dust Bunnies of NGC 891
18.03.1998

What is going on in NGC 891? This galaxy appeared previously to be very similar to our own Milky Way Galaxy: a spiral galaxy seen nearly edge-on. However, recent high-resolution images of NGC 891's dust show unusual filamentary patterns extending well away from its Galactic disk.

A Red Dome Under the Big Dipper
21.08.2007

Why would the dome of a telescopic observatory appear translucent red? As one of the telescopes of the Etscorn Observatory of New Mexico Tech waited to inspect small portions of the night sky, playful observers decided to make this unusual image.

Mercury Chases the Sunset
12.01.2008

This colorful view of the western sky at sunset features last Wednesday's slender crescent Moon. Of course, when the Moon is in its crescent phase it can never be far from Sun in the sky.

A Close Up or Martian Soil
18.01.2004

Make your background the closest image of Mars yet. The Spirit Rover currently rolling on Mars has taken the highest resolution image to date of another planet. The above black and white image spans only about 1.5 centimeters across, with details smaller than 1/10 of a millimeter visible.

Lenticular Clouds Over Washington
4.11.2012

Are those UFOs near that mountain? No -- they are multilayered lenticular clouds. Moist air forced to flow upward around mountain tops can create lenticular clouds. Water droplets condense from moist air cooled below the dew point, and clouds are opaque groups of water droplets.

APOD: 2023 February 12 Б Mammatus Clouds over Nebraska
12.02.2023

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.

Ganymede: The Largest Moon in the Solar System
20.06.2000

If Ganymede orbited the Sun, it would be considered a planet. The reason is that Jupiter's moon Ganymede is not only the largest moon in the Solar System, it is larger than planets Mercury and Pluto.

Asteroid 1998 WT24 Passes Near Earth
24.12.2001

Last week, an asteroid approached unusually close to the Earth. Passing well outside the orbit of our Moon, Asteroid 1998 WT24 posed no danger, but became bright enough to see with binoculars and to track with radar. Pictured above, the kilometer-sized asteroid was imaged crossing the sky on December 14, two days before closest approach.

Quasar in an Elliptical Galaxy
9.04.1998

Where do quasars live? Quasars are the brightest objects in the universe, so bright they can be seen from across the universe. Observations continue to show that most quasars are surrounded by a relatively faint nebulous patch. Astronomers are trying to identify the nature of these patches.

M13: The Great Globular Cluster in Hercules
11.05.2004

M13 is one of the most prominent and best known globular clusters. Visible with binoculars in the constellation of Hercules, M13 is frequently one of the first objects found by curious sky gazers seeking celestials wonders beyond normal human vision.