Messier Catalog at Uniform ScaleWhat are some of the most interesting astronomical objects you can see in the night sky? Armed with a good pair of binoculars or a small telescope, if you live in the Northern Hemisphere, you can look for the very popular objects in the Messier Catalog. Most of them, but not all, are also visible from the…Read More

NGC 188: Old Cluster in the New General CatalogThe New General Catalog of star clusters and nebulae really isn’t so new. In fact, it was published in 1888 – an effort by J. L. E. Dreyer to consolidate the work of astronomers William, Caroline, and John Herschel along with others into a useful single, complete catalog of astronomical discoveries…Read More

Comet R3 PanSTARRS Before RigelWhich way is Comet R3 PanSTARRS going? Not towards the star at the top of the image, because that is Rigel, which, being far in the background, is unrelated to the comet. Not through the nebula in the image middle, because that is the Witch Head Nebula and it, too, is far in the distance — but not far from Rigel. …Read More

Supernova in a Sideways SpiralA long time ago, in a distant galaxy, a massive star was destroyed in a supernova explosion. The light of this event travelled for tens of millions of years and reached Earth last week as Supernova 2026kid. The featured video shows a time-lapse over three nights of the host galaxy NGC 5907, an edge-on spiral also…Read More

Supernova in a Sideways SpiralA long time ago, in a distant galaxy, a massive star was destroyed in a supernova explosion. The light of this event travelled for tens of millions of years and reached Earth last week as Supernova 2026kid. The featured video shows a time-lapse over three nights of the host galaxy NGC 5907, an edge-on spiral also…Read More

The Retrograde Dance of Saturn and NeptuneWhat does it mean for Saturn and Neptune to be in retrograde? Featured is a composite of images taken over 34 nights from May 2025 to February 2026 tracing Saturn (brighter, foreground) and Neptune (dimmer, background). Over that time, the two planets exhibited retrograde motion, meaning they appeared to…Read More

The Retrograde Dance of Saturn and NeptuneWhat does it mean for Saturn and Neptune to be in retrograde? Featured is a composite of images taken over 34 nights from May 2025 to February 2026 tracing Saturn (brighter, foreground) and Neptune (dimmer, background). Over that time, the two planets exhibited retrograde motion, meaning they appeared to…Read More

Orion over Mount TeideOrion is rarely seen like this. To achieve this majestic vista, you need a camera capable of taking such long duration exposures that faint features in the night sky become revealed. Iconic nebulas that appear include the Orion Nebula, the Flame Nebula, and Barnard’s Loop. For contrast, it also helps to have a volcano on…Read More

Superplumes Inside EarthWhy are there huge, unusual masses inside the Earth? No one is sure. By noting how earthquakes rumble through our planet’s interior, humanity has discovered two deep structures that appear to have unusual temperatures and/or chemical compositions. One hypothesis holds that the superplumes are sunken debris left over from…Read More

Trifid Pillars and JetsDust pillars are like interstellar mountains. They survive because they are more dense than their surroundings, but they are slowly being eroded away by a hostile environment. Visible in the featured picture by the Hubble Space Telescope is the end of a huge gas and dust pillar in the Trifid Nebula (M20), punctuated by a…Read More

Seeing TitanShrouded in a thick atmosphere, the surface of Saturn’s largest moon, Titan, is really hard to see. Small particles suspended in Titan’s upper atmosphere cause an almost impenetrable haze, strongly scattering light at visible wavelengths and hiding surface features from prying eyes. Still, Titan’s surface is better imaged at infrared…Read More

Markarian’s ChainNear the heart of the Virgo Galaxy Cluster, a string of galaxies known as Markarian’s Chain stretches across this telescopic field of view. Anchored in the frame at bottom right by prominent lenticular galaxies, M84 (bottom) and M86, you can follow the chain’s gentle arc up and toward the left. Near center you’ll spot the pair of…Read More

Waves on TitanHave you ever thought about surfing on an alien world? We can now expand the search for the perfect wave from Earth to the rest of the Solar System, and beyond. Scientists have developed a new model for simulating waves on other planets. Titan is one of the 274 confirmed moons of Saturn to date, and the only object in the solar…Read More

The Moon, Venus, and the PleiadesNo, Earth did not recently acquire six more moons! Today’s APOD is a combination of images following the Moon, Venus, and the Pleiades across a southern Sicilian sky as twilight turned to evening on April 19. From 2023 to 2029, the Pleiades’ and the Moon “visit” each other once per month due to the Pleiades’ loc…Read More

CG 30: Cometary GlobulesThey’re like mountain peaks, but they are forming stars. Bright-rimmed, flowing shapes gather near the center of this rich starfield toward the borders of the nautical southern constellations Puppis and Vela. Composed of interstellar gas and dust, the grouping of light-year sized cometary globules is about 1300 light-years…Read More

Comet R3 PanSTARRS Behind Satellite TrailsCan you find the comet? Somewhere through this web of satellite trails is Comet C/2025 R3 (PanSTARRS), a bright visitor passing through the inner Solar System. Now, the orbiting satellites themselves only appear as streaks because of the long camera exposure, over 10 minutes in this case. On the contrary,…Read More

Mystic Mountain Monster being DestroyedInside the head of this interstellar monster is a star that is slowly destroying it. The huge monster, actually an inanimate series of pillars of gas and dust, measures light years in length. The in-head star is not itself visible through the opaque interstellar dust but is bursting out partly by ejecting…Read More

The Persistence of SunlightThis seaside sunset offered a surreal experience, captured in a sea and skyscape from the west coast of Sardinia, Italy, planet Earth. The Daliesque scene is a composition of sequential exposures made with a camera and long telephoto lens. The Sun is not melting, though. Its shifting and fluid appearance as it nears the…Read More

Young Moon and Sister StarsSunlit arms of a crescent moon seem to embrace the faint lunar night side in this dramatic celestial scene from planet Earth. The single telephoto exposure tracking the sky was captured on the night of April 19, when a two day old Moon was near perigee in its elliptical orbit. On that date, the young Moon was also close…Read More

Large Scale Structure of the UniverseThis is a map of the universe. The Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory, Arizona, has finished its five-year survey. It observed more than 47 million galaxies and quasars and created a 3D map centered on the Earth. Today’s featured image shows a thin slice of these data:…Read More

Earthset with an iPhoneWhat does it mean for the Earth to set? Artemis II Commander Reid Wiseman gave us another spectacular view of Earth from their historic flyby of the Moon. Commander Wiseman’s video, taken with an iPhone at 8x zoom, shows our entire planet gradually blocked from view by the Moon. On the Earth, the 24-hour planetary rotation…Read More

Three Sky Arches over Snowy AlpsWhy are there three arches across the sky instead of two? Last month, after being dropped off by a helicopter at a high mountain peak in the Alps near the Swiss Italian border, an adventurous astrophotographer expected two arches of our Milky Way galaxy to be visible during the night. These were the inner arch…Read More

Comet R3 PanSTARRS over a Himalayan ValleyThe best way to see comet R3 PanSTARRS’s long tail is with a camera. This week, the recently brightened comet appears in northern skies to the east just before dawn, but is only barely visible to the unaided eye. The many-degree ion tail captured on long duration camera exposures is not unusual for a c…Read More

Eye on the Milky WayHave you ever had stars in your eyes? It appears that the eye on the left does, and moreover, it appears to be gazing at even more stars. The featured 27-frame mosaic was taken in 2019 from Ojas de Salar in the Atacama Desert of Chile. The eye is actually a small lagoon captured reflecting the dark night sky as the Milky Way…Read More

PanSTARRS and PlanetsNear the eastern horizon before sunrise, Comet C/2025 R3 PanSTARRS is getting brighter. Readily visible in binoculars and small telescopes, the comet may be just on the verge of naked-eye visibility from dark sky sites. Though it was not quite apparent to the eye, PanSTARRS is still easy to spot in this camera image taken on…Read More

M82: Starburst Galaxy with a SuperwindMessier 82 is a starburst galaxy with a superwind. In fact, through supernova explosions and powerful winds from massive stars, the burst of star formation in M82 is driving a prodigious outflow. Evidence for the superwind from the galaxy’s central regions is clear in the sharp telescopic portrait. The…Read More

South Celestial TreeIf you live in the northern hemisphere, you may have learned how to locate the North Star, Polaris, in the night sky. It can be used to find north, and it approximately marks the northern celestial pole. If you live in the southern hemisphere, there is no bright star marking the southern celestial pole, but the Southern Cross…Read More

The ISS Transits the MoonNope, that is not an alien spaceship landing on the Moon! This is an image of the International Space Station (ISS) as it begins to transit in front of the Moon. The ISS is in low-Earth orbit (LEO) where it wizzes around the Earth every 90 minutes. Orbiting the Earth 16 times per day for 25 years, the ISS has photobombed…Read More

The Long Wispy Tail of Comet R3 (PanSTARRS)Why does Comet R3 (PanSTARRS) have a wispy tail? The newest bright member of the inner Solar System, Comet C/2025 R3 (PanSTARRS) is already extending an impressive stream of glowing gas. This tail starts from an unseen central nucleus of dirty ice that is likely a few kilometers across. The nucleus is…Read More

NGC 602 and BeyondThe clouds may look like an oyster, and the stars like pearls, but look beyond. Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the…Read More

Comet R3 (PanSTARRS) BrightensComet R3 is brightening rapidly — will it survive? C/2025 R3 (PanSTARRS) has been slowly brightening and extending an ion tail since its discovery last year. This shedding mountain of dirty ice puts on its best sky show this month, though, because it passes its closest to both the Sun (April 19) and the Earth…Read More

Artemis II: Flight Day 6On flight day 6 (April 6) the Artemis II mission achieved a historic lunar flyby. Rounding the lunar far side, the deep space maneuver marked humanity’s first venture to the Moon since Apollo 17 in 1972. The Orion spacecraft Integrity reached a maximum distance of nearly 407,000 kilometers, and the Artemis II crew, Reid…Read More

Exploring the AntennaeSome 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. Stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm that lasts for hundreds of millions of years. But the galaxies’ large clouds of molecular gas and…Read More

Destruction of Comet C/2026 A1 (MAPS)As the crew of Artemis II travelled towards the Moon this week, Comet C/2026 A1 (MAPS) was expected to have its closest approach to the Sun on Monday. At this point, comet and Sun would be closer than half the distance separating the Earth and Moon. The comet did not survive; the featured video was made with 40…Read More

IC 4592: The Blue Horsehead Reflection NebulaDo you see the horse’s head? What you are seeing is not the famous Horsehead nebula toward Orion, but rather a fainter nebula that only takes on a familiar form with deeper imaging. The main part of the here-imaged molecular cloud complex is reflection nebula IC 4592. Reflection nebulas are made up…Read More

The Path of Artemis IIWhy doesn’t Artemis II land on the Moon? The main reason is that Artemis II is primarily a test mission designed to make a future Artemis missions — which will land humans on the Moon — better prepared. Similarly, NASA’s Apollo 8 and Apollo 10 went right near the Moon as tests before Apollo 11 — which landed. As the…Read More

The Path of Artemis IIWhy doesn’t Artemis II land on the Moon? The main reason is that Artemis II is primarily a test mission designed to make a future Artemis missions — which will land humans on the Moon — better prepared. Similarly, NASA’s Apollo 8 and Apollo 10 went right near the Moon as tests before Apollo 11 — which landed. As the…Read More

NGC 3310: A Starburst Spiral GalaxyThe party is still going on in spiral galaxy NGC 3310. Roughly 100 million years ago, NGC 3310 likely collided with a smaller galaxy causing the large spiral galaxy to light up with a tremendous burst of star formation. The changing gravity during the collision created density waves that compressed existing…Read More

Hello WorldFrom pole to pole our fair planet is captured in this snapshot from space, an evocative image from a window of the Orion spacecraft Integrity. From the spacecraft’s perspective the Sun is moving behind Earth’s bright limb along the lower right. Africa and the Iberian peninsula are in view on the pale blue planet’s surface, while aurorae…Read More

Caught in the Web: Visualization of a Black Hole Merger in the Tarantula NebulaHow can we see what is invisible? Black holes are not easy to see in the dark cosmic night, but astronomers can find them by analyzing their gravitational effects on matter, light and spacetime. The featured image shows an illustration that combines a simulation of a…Read More

Liftoff! Returning to the MoonWe are one small step closer to returning to the Moon. A new chapter in human exploration began yesterday when NASA’s Artemis II launched aboard the Space Launch System (SLS) from Kennedy Space Center. Carrying four astronauts, the Orion spacecraft’s planned lunar flyby will be the first in over half a century. This…Read More

The Claw and Bubble NebulaeWhat unexpected things do you see when you look up at the night sky? Today’s image resembles an abstract painting, with large swaths of color strewn across a cosmic canvas seemingly without design. Despite the image’s abstract nature, the human mind finds patterns, identifying a large claw reaching up towards a f…Read More

Uranus’s Largest Moon: TitaniaTitania’s tortured terrain is a mix of canyons, cliffs, and craters. NASA’s interplanetary robot spacecraft Voyager 2 passed the largest moon of Uranus in 1986 and took the feature picture. That the trenches of Titania resemble those on another moon of Uranus, Ariel, indicate that Titania underwent some violent…Read More

Peculiar Elliptical Galaxy Centaurus AWhat’s happened to the center of this galaxy? Dramatic dust lanes run across the center of unusual elliptical galaxy Centaurus A. These dust lanes are so thick they almost completely obscure the galaxy’s center in visible light. This is particularly unusual as Cen A’s older stars and oval shape are…Read More

A Message from EarthWhat are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of an upgrade to the Arecibo Observatory – then the largest single radio telescope in the world – a string of 1’s and 0’s representing the diagram was sent. This…Read More

Robert Goddard and NellRobert H. Goddard, considered the father of modern rocketry, was born in Worcester Massachusetts in 1882. As a 16 year old, Goddard read H.G. Wells’ science fiction classic “War Of The Worlds” and dreamed of space flight. By 1926 he had designed, built, and flown the world’s first liquid fuel rocket. Launched 100 years ago,…Read More

Hickson 44 in LeoScanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups. The four prominent galaxies seen in this intriguing telescopic skyscape are one such group, Hickson 44. The Hickson 44 galaxy group is about 100 million…Read More

Black Holes and Neutron Stars: 218 Mergers and CountingWhat is the sound of two black holes merging in deep space? Sound waves don’t propagate in vacuum, but gravitational waves do. In 2015 we were able to “hear” them for the first time and confirm one of Albert Einstein’s theoretical predictions. Each square on the grid of the featured image…Read More

The Guardians of Rapa Nui beneath the Milky WayIn the words of today’s astrophotographer, Rositsa Dimitrova, “What have these silent sentinels watched pass across the sky?” The volcanic mo’ai (meaning statue) of Ahu Tongariki stand guard over Rapa Nui (Isla de Pascua, Easter Island), a Polynesian island (annexed by Chile in 1888) located thousands…Read More

A Gravity Map of EarthIs gravity the same over the surface of the Earth? No — in some places you will feel slightly heavier than others. The featured Earth map video shows in colors and exaggerated highs and lows where the gravitational field of Earth is relatively strong and weak. A low spot, where you would feel slightly lighter, can be seen…Read More