Casper Astronomy

Astronomy Picture of the Day 📸 25 September 2025 📅

"Saturn Opposite the Sun"

On September 21 this year, Saturn reached opposition—directly opposite the Sun in Earth’s sky 🌌. At its closest and brightest, it rose at sunset and stayed visible all night among the dim stars of Pisces ♓. In a photo from Qinghai Lenghu Observatory on China’s Tibetan Plateau, Saturn appears surrounded by a soft, oval glow called the gegenschein 🌕—sunlight scattered by interplanetary dust along the ecliptic. Together, Saturn and the gegenschein resemble a cosmic eye gazing down at the telescope domes, with vivid atmospheric airglow painting the horizon 🎨

Image Credit & Copyright: Jin Wang

#space #astrophoto #astrophotography #science #universe #moon

18 hours ago | [YT] | 27

Casper Astronomy

Astronomy Picture of the Day 📸 24 September 2025 📅

"GW250114: Rotating Black Holes Collide"

GW250114 was the most powerful gravitational wave signal ever recorded. Detected earlier this year by both LIGO observatories in Washington and Louisiana, it revealed the merger of two black holes—each about 33 times the Sun’s mass—into a single black hole roughly 63 solar masses. Despite occurring a billion light-years away, the signal was so clear that scientists precisely measured the spin of the black holes and the initial vibrations of the final one. The event also confirmed a key prediction: the total event horizon area of the resulting black hole is larger than the combined areas of the originals. An artist’s illustration imagines the view near one of the black holes just before the collision.

Image Credit & Copyright: Aurore Simonnet (SSU/EdEon), LVK, URI; LIGO Collaboration

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1 day ago | [YT] | 56

Casper Astronomy

Astronomy Picture of the Day 📸 22 September 2025 📅

"Equinox at Saturn"

Since Saturn's grand rings orbit along the planet's equator, these rings appear most prominent -- from the direction of the Sun -- when the spin axis of Saturn points toward the Sun. Conversely, when Saturn's spin axis points to the side, an equinox occurs, and the edge-on rings are hard to see from not only the Sun -- but Earth.

Image Credit & Copyright: Imran Sultan

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2 days ago | [YT] | 38

Casper Astronomy

Astronomy Picture of the Day 📸 21 September 2025 📅

"Equinox Sunset"

Image Credit & Copyright: Luca Vanzella

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3 days ago | [YT] | 22

Casper Astronomy

Astronomy Picture of the Day 📸 20 September 2025 📅

"Gibbous vs Crescent"

Image Credit & Copyright: Luca Bartek

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4 days ago | [YT] | 27

Casper Astronomy

Astronomy Picture of the Day 📸 19 September 2025 📅

"The NGC 6914 Complex"

NGC 6914 Complex 🌌:

📍 Located about 6,000 light-years away in the constellation Cygnus, near the plane of the Milky Way.

🔴 Features glowing red hydrogen emission nebulae and dusty blue reflection nebulae, creating a stunning contrast.

💡 Illuminated by hot, young stars from the Cygnus OB2 association, whose ultraviolet light energizes the surrounding gas.

🕶️ Interstellar dust clouds appear in silhouette, adding dramatic depth to the region.

📷 The complex spans about 100 light-years, making it a rich field for astrophotography and study.

Image Credit & Copyright: Tommy Lease

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5 days ago | [YT] | 55

Casper Astronomy

Astronomy Picture of the Day 📸 18 September 2025 📅

"Comet C/2025 R2 (SWAN)"

A new visitor from the outer Solar System, comet C/2025 R2 (SWAN) also known as SWAN25B was only discovered on September 11. That's just a day before the comet reached perihelion, its closest approach to the Sun.

Image Credit & Copyright: Team Ciel Austral

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6 days ago | [YT] | 77

Casper Astronomy

Astronomy Picture of the Day 📸 17 September 2025 📅

"Nebulas and Clusters in Sagittarius"


18th-century astronomer Charles Messier cataloged only two of them: the bright Lagoon Nebula (M8) at the bottom, and the colorful Trifid Nebula (M20) at the upper right. The one on the left that resembles a cat's paw is NGC 6559, and it is much fainter than the other two.




Image Credit & Copyright: J. De Winter, C. Humbert, C. Robert & V. Sabet; Text: Ogetay Kayali (MTU)


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1 week ago | [YT] | 58

Casper Astronomy

Astronomy Picture of the Day 📸 16 September 2025 📅

"New Comet SWAN25B over Mexico"


The comet, C/2025 R2 (SWAN) and nicknamed SWAN25B, is brightening significantly as it emerges from the Sun's direction and might soon become visible on your smartphone -- if not your eyes.




Image Credit & Copyright: Daniel Korona


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1 week ago | [YT] | 46

Casper Astronomy

Astronomy Picture of the Day 📸 13 September 2025 📅

"Star Trails over One-Mile Radio Telescope"


🏗️ Built in 1964 by the University of Cambridge, it's located at the Mullard Radio Astronomy Observatory in England.

📏 As the name suggests, its baseline spans one mile, using three 18-meter dishes.

🌌 It was designed for interferometry, combining signals from multiple dishes to study radio sources in deep space.

🧠 Played a key role in mapping radio galaxies and understanding quasars.

🛰️ Though retired, it helped pave the way for modern radio astronomy and large-scale sky surveys.



Image Credit & Copyright: Joao Yordanov Serralheiro


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1 week ago | [YT] | 42