The Annotated Galactic Center
11.09.1999

The sky toward the center of our Galaxy is filled with a wide variety of celestial wonders. Many are easily visible with binoculars. Constellations near the galactic center include Sagittarius, Libra, Scorpius, Scutum, and Ophiuchus. Nebulae include Messier Objects M8, M16, M17, M20 and the Pipe Nebula.

M45: The Pleiades Star Cluster
9.12.2008

Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters.

Paris by Night
31.03.2012

Do you recognize the city lights of Paris in this picture? Taken on March 25 from the top of the 210 meter tall Montparnasse skyscraper, many will spot the looming Eiffel Tower, or the large domed structure of Les Invalides (right), or the colorfully lit elevated Metro train line gently curving toward picture center.

The Comet and the Star Cluster
11.04.2016

Comet Linear has become unexpectedly bright. The comet, discovered in 2000, underwent a 100-fold outburst just a week before it passed a mere 14 lunar distances from Earth late last month. The comet...

APOD: 2024 August 5 Б Milky Way Over Tunisia
5.08.2024

That's no moon. On the ground, that's the Lars Homestead in Tunisia. And that's not just any galaxy. That's the central band of our own Milky Way galaxy. Last, that's not just any meteor. It is a bright fireball likely from last year's Perseids meteor shower.

The Same Color Illusion
17.07.2007

Are square A and B the same color? They are. Are too. To verify this, click on the above image to see them connected. The above illusion, called the same color illusion, illustrates that purely human observations in science may be ambiguous or inaccurate. Even such a seemingly direct perception as relative color.

In Green Company: Aurora over Norway
2.11.2014

Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display.

Lapland Northern Lights
8.04.2016

Early spring in the northern hemisphere is good season for aurora hunters. Near an equinox Earth's magnetic field is oriented to favor interactions with the solar wind that trigger the alluring glow of the northern lights. On March 28/29 the skies over Kaunispää Hill, Lapland, Finland did not disappoint.

La Silla Eclipse Sequence
5.07.2019

The road to the high mountaintop La Silla Observatory in the Chilean Atacama Desert also led in to the path of July 2nd's total solar eclipse. Recorded at regular intervals before and after...

The Pleiades Star Cluster
27.02.2000

It is the most famous star cluster on the sky. The Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters.