If not perfect, then this spiral galaxy is at least one of the most photogenic. An island universe containing billions of stars and situated about 40 million light-years away toward the constellation of the Dolphinfish (Dorado), NGC 1566 presents a gorgeous face-on view. Classified as a grand design spiral, NGC 1566 shows two prominent and graceful spiral arms that are traced by bright blue star clusters, red emission nebulas, and dark cosmic dust lanes. Numerous Hubble Space Telescope images of NGC 1566 have been taken to study star formation, supernovas, and the spiral's unusually active center. NGC 1566's flaring center makes the spiral one of the closest and brightest Seyfert galaxies, likely housing a central supermassive black hole wreaking havoc on surrounding stars and gas. Sky Surprise: What picture did APOD feature on your birthday? (after 1995)

To see the feathered serpent descend the Mayan pyramid requires exquisite timing. You must visit El Castillo -- in Mexico's Yucatán Peninsula -- near an equinox. Then, during the late afternoon if the sky is clear, the pyramid's own shadows create triangles that merge into the famous illusion of a slithering viper. Also known as the Temple of Kukulkan, the impressive step-pyramid stands 30 meters tall and 55 meters wide at the base. Built up as a series of square terraces by the pre-Columbian civilization between the 9th and 12th century, the structure can be used as a calendar and is noted for astronomical alignments. The featured composite image was captured in 2019 with Jupiter and Saturn straddling the diagonal central band of our Milky Way galaxy. In a few days another equinox will occur -- not only at Temple of Kukulcán, but all over planet Earth.

Want to visit a planet that has 3.14 days in a year? Then plan a trip to K2-315b, an earth-sized planet orbiting around a cool, red, M dwarf star about once every 3.14 days. The exoplanet's discovery, based on publicly available data from the planet-hunting Kepler Space Telescope's extended K2 mission, was announced in 2020. K2-315b's measured orbital period in days is nearly equal to the extremely popular irrational number Pi. That puts the exoplanet so close to its parent star that its surface is likely very warm, baking-hot in fact. And this Pi planet is over 185 light-years away. So instead of trying to arrange for an interstellar vacation to K2-315b, there may be easier and more comfortable ways for you to celebrate Pi day on planet Earth.

In this composited night skyscape, stacked exposures trace graceful star trails above Lake Toolondo, Victoria, Australia, planet Earth. Captured while the lunar eclipse of March 3 was in progress, the exposures used were made during the hour-long total eclipse phase. So faint star trails are easily visible along with the trail of the reddened Moon in eclipse-darkened skies above the lake and trees. Of course, the apparent motion of Moon and stars revealed in the timelapse composite reflect the Earth's daily rotation around its axis. Dramatically punctuating the Moon's trail as totality ended, a single, separate telephoto image of the totally eclipsed Moon was scaled and blended into the scene. Growing Gallery: Total Lunar Eclipse of March 3

Is this a cosmic monster ready to devour an unsuspecting galaxy? Thankfully, that is not the case. The red “monster” shown in the featured image is Cometary Globule CG 4, 1,300 light-years away in the Constellation Puppis. CG 4 is a molecular cloud, where hydrogen becomes cold enough to form molecules that can be brought together by gravity to create stars. The shape of CG 4 resembles that of a comet, but its head is 1.5 light-year in diameter and its tail is 8 light-years long; for comparison, the distance from the Earth to the sun is only 8 light-minutes. Astronomers believe that the tail of a cometary globule could have been shaped by a nearby supernova explosion or by irradiation from hot, massive stars. Indeed, CG 4 and other nearby globules point away from the Vela Supernova Remnant, at the center of the Gum Nebula. The edge-on spiral galaxy, ESO 257-19, is more than a hundred million light-years beyond CG 4, and is completely safe from the “monster”.

Are lasers from giant telescopes being used to defend the Earth? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some directions, Earth atmosphere-induced fluctuations in starlight can indicate how the air mass over a telescope is changing, but in other directions, no bright star exists. In these directions, astronomers can create an artificial star with a laser. Subsequent observations of the artificial laser guide star can reveal information so detailed about the changing blurring effects of the Earth's atmosphere that much of it can be removed by rapidly flexing a telescope's mirror. Such adaptive optics techniques allow high-resolution ground-based observations of real stars, planets, and nebulas. Pictured here, telescopes at Paranal Observatory in Chile study a colorful sky filled with green airglow and the Magellanic Clouds on the left, red airglow on the right, and the majestic central band of our Milky Way Galaxy arching across the center.

What's going on inside the head of this nebula? Dubbed the Exposed Cranium Nebula for its similarity to the human brain, what created the nebula remains a mystery. One thought is that the Cranium Nebula, also known as PMR 1, is a planetary nebula surrounding a white dwarf star. In this mode, the outer atmosphere was expelled when the original Sun-like star ran out of central nuclear fuel and contracted. A competing thought is that the central star is much more massive, possibly a Wolf-Rayet star, that is ejecting gas and dust via turbulent stellar winds. Adding to the intrigue is the dark vertical central division and the thin outer gaseous shell. The featured image was taken by the Webb Space Telescope in mid- infrared light, while a second image, included as a rollover, is in near-infrared. Future observations may reveal if this brainy system will quietly just fade from view or, many years from now, suddenly erupt in a powerful supernova.