Photo of the Day On August 12, the Moon's shadow reached out to touch our fair planet. Beginning in the Arctic Ocean, it swept along a narrow track that led the dark lunar umbra across parts of Greenland, Iceland, the Atlantic, Portugal, and northern Spain. And for a moment, denizens of Earth who found [...]
Photo of the Day On August 12th, 2026, the Moon totally eclipsed the Sun and cast its shadow across Siberia, Greenland, Iceland, Spain, and Portugal. Today’s image features two total solar eclipses viewed from Zaragoza, Spain, one over the Cathedral-Basilica of Our Lady of the Pillar and the other reflecting in the Ebro River. [...]
Photo of the Day It looks like a view from the Little Prince's planet. The featured image is a throwback to the 2024 Perseid meteor shower, surrounded in this projection by the Bieszczady Mountains in Poland. Visible in the sky is the arch of the Milky Way, along with several nebulas in red and [...]
Photo of the Day Which of these is not a comet? You guessed it - the one on the right is a globular star cluster. The diffuse greenish coma of periodic comet 10P/Tempel 2 is at left in the frame. In fact the globular star cluster is Messier 30, also known as M30, or [...]
Photo of the Day What does the new sharpest image of our Sun show? Instability. To be clear, a certain kind of interactive process called the Kelvin-Helmholtz instability (KHI). This instability can create waves and swirls when two streams flow past each other -- in this case variable streams of solar magnetic plasma. Long [...]
Photo of the Day Don’t get spooked by Saturn’s ghostly spokes! Today we feature a nearly two-hour timelapse of Saturn and its rings looping forwards and backwards. A day on Saturn is only 10 hours long, so two hours of observation covers quite a bit of its rotation. If you look closely, a ghoulish [...]
Photo of the Day What causes unusual knots of gas and dust in planetary nebulas? Seen also in the Ring Nebula, the Dumbbell Nebula and NGC 2392, the knots' existence was not initially predicted, and their origins are still not well understood. Pictured here is a fascinating image of part of the Helix Nebula [...]
Photo of the Day What's happening to this meteor? This bright meteor streak appeared and disappeared quickly during a long exposure of the Great Lacerta Nebula, seen faintly in red toward the center of the image. The meteoroid, likely a small pebble, creates its glow partly by heating and exciting surrounding air in Earth's [...]
Photo of the Day What's happening to this cloud? Ice crystals in a distant cirrus cloud are acting like little floating prisms. Known informally as a fire rainbow for its flame-like appearance, a circumhorizon arc appears parallel to the horizon. For a circumhorizontal arc to be visible, the Sun must be at least 58 [...]
Photo of the Day The Buck Moon is a traditional name for the full moon of July. In this colorful Adriatic sea and skyscape captured on July 28 from Krk Island along the coast of Croatia, a full Buck Moon is just rising over distant mountains. Since a full moon rises as the Sun [...]
