Highlights of the Summer Sky
4.06.2017

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

NGC 7814: The Little Sombrero in Pegasus
29.06.2017

Point your telescope toward the high flying constellation Pegasus and you can find this expanse of Milky Way stars and distant galaxies. Dominated by NGC 7814, the pretty field of view would almost be covered by a full moon.

Venus and the Triply Ultraviolet Sun
3.02.2018

An unusual type of solar eclipse occurred in 2012. Usually it is the Earth's Moon that eclipses the Sun. That year, most unusually, the planet Venus took a turn. Like a solar eclipse by the Moon, the phase of Venus became a continually thinner crescent as Venus became increasingly better aligned with the Sun.

APOD: 2023 January 25 Б LDN 1622: The Boogeyman Nebula
24.01.2023

To some, the dark shape looks like a mythical boogeyman. Scientifically, Lynds' Dark Nebula (LDN) 1622 appears against a faint background of glowing hydrogen gas only visible in long telescopic exposures of the region.

Northern Lights from the Stratosphere
17.01.2024

Northern lights shine in this night skyview from planet Earth's stratosphere, captured on January 15. The single, 5 second exposure was made with a hand-held camera on board an aircraft above Winnipeg, Canada. During the exposure, terrestrial lights below leave colorful trails along the direction of motion of the speeding aircraft.

APOD: 2024 June 9 Б How to Identify that Light in the Sky
8.06.2024

What is that light in the sky? The answer to one of humanity's more common questions may emerge from a few quick observations. For example -- is it moving or blinking?

A Sky Full Of Hydrogen
17.12.1996

Interstellar space is filled with extremely tenuous clouds of gas which are mostly Hydrogen. The neutral hydrogen atom (HI in astronomer's shorthand) consists of 1 proton and 1 electron. The proton and electron spin like tops but can have only two orientations; spin axes parallel or anti-parallel.

M27: The Dumbbell Nebula
3.06.2005

The first hint of what will become of our Sun was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets.

Water Claimed in Evaporating Planet HD 209458b
17.04.2007

Planet HD 209458b is evaporating. It is so close to its parent star that its heated atmosphere is simply expanding away into space. Some astronomers studying this distant planetary system now believe they have detected water vapor among the gases being liberated.

The Large Cloud of Magellan
28.05.2013

The 16th century Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two fuzzy cloud-like objects easily...