The Astronomy Picture of the Day is a wonderful web site that puts up a different astronomy-related picture every day. However, the site does not have an RSS feed. This page fixes that deficiency.
Updated: 3 hours 14 min ago
Lunar Corona over Cochem Castle This bat-like apparition does not shine on clouds passing over Gotham city. Instead, the cloud bank in silhouette against a colorful lunar corona was spotted on the evening of May 18 over Cochem, Germany from the banks of the river Mossele. The lunar corona is formed as bright moonlight is diffracted by water droplets in thin clouds drifting in front of the lunar disk. Below it lies the region's historic Cochem Castle dating from the 11th century, and not Wayne Manor. Still, regardless of your location on planet Earth it is well worth scanning the evening skies this weekend, as a Full Moon rises and bright planets gather in the west.
Caterpillar Moon A close series of consecutive exposures are combined in this intriguing composite of the Full Moon slowly crawling, across the sky. Beginning on the upper right at 19:42 UT and ending at 22:14 UT on April 25, the sequence follows the Moon from Germany as it passes through Earth's shadow in a partial lunar eclipse. Near the top, the Moon just grazes the southern edge of Earth's dark central shadow, or umbra. But the decreased brightness in the darker part of the outer shadow region, the penumbra, is also apparent on the lunar disk. In fact, the relative size and shape of the Earth's shadow regions and the Moon are easier to see along the segments of this lunar caterpillar. Nearly impossible to follow with the eye though, a penumbral lunar eclipse, the Full Moon passing only through the pale outer penumbral shadow, will begin on May 25.
Messier 109 Beautiful barred spiral galaxy M109, 109th entry in Charles Messier's famous catalog of bright Nebulae and Star Clusters, is found just below the Big Dipper's bowl in the northern constellation Ursa Major. In telescopic views, its striking central bar gives the galaxy the appearance of the Greek letter "theta", θ, a common mathematical symbol representing an angle. Of course M109 spans a very small angle in planet Earth's sky, about 7 arcminutes or 0.12 degrees. But that small angle corresponds to an enormous 120,000 light-year diameter at the galaxy's estimated 60 million light-year distance. The brightest member of the now recognized Ursa Major galaxy cluster, M109 (aka NGC 3992) is joined by three spiky foreground stars strung out across this frame. The three small, fuzzy bluish galaxies also on the scene, identified left to right as UGC 6969, UGC 6940 and UGC 6923, are possibly satellite galaxies of the larger M109.
Comet PanSTARRS Anti-Tail Once the famous sunset comet, PanSTARRS (C/2011 L4) is now visible all night from much of the northern hemisphere, bound for the outer solar system as it climbs high above the ecliptic plane. Dimmer and fading, the comet's broad dust tail is still growing, though. This widefield telescopic image was taken against the starry background of the constellation Cepheus on May 15. It shows the comet has developed an extensive anti-tail, dust trailing along the comet's orbit (to the left of the coma), stretching more than 3 degrees across the frame. Since the comet is just over 1.6 astronomical units from planet Earth, that corresponds to a distance of over 12 million kilometers. In late May Comet PanSTARRS will pass within a few degrees of the north celestial pole.
The Waterfall and the World at Night Above this boreal landscape, the arc of the Milky Way and shimmering aurorae flow through the night. Like an echo, below them lies Iceland's spectacular Godafoss, the Waterfall of the Gods. Shining just below the Milky Way, bright Jupiter is included in the panoramic nightscape recorded on March 9. Faint and diffuse, the Andromeda Galaxy (M31) appears immersed in the auroral glow. The digital stitch of four frames is a first place winner in the 2013 International Earth and Sky Photo Contest on Dark Skies Importance organized by The World at Night. An evocative record of the beauty of planet Earth's night sky, all the contest's winning entries are featured in this video.
Four X-class Flares Swinging around the Sun's eastern limb on Monday, a group of sunspots labeled active region AR1748 has produced the first four X-class solar flares of 2013 in less than 48 hours. In time sequence clockwise from the top left, flashes from the four were captured in extreme ultraviolet images from the Solar Dynamics Observatory. Ranked according to their peak brightness in X-rays, X-class flares are the most powerful class and are frequently accompanied by coronal mass ejections (CMEs), massive clouds of high energy plasma launched into space. But CMEs from the first three flares were not Earth-directed, while one associated with the fourth flare may deliver a glancing blow to the Earth's magnetic field on May 18. Also causing temporary radio blackouts, AR1748 is likely not finished. Still forecast to have a significant chance of producing strong flares, the active region is rotating into more direct view across the Sun's nearside.
Cape York Annular Eclipse This week the shadow of the New Moon fell on planet Earth, crossing Queensland's Cape York in northern Australia ... for the second time in six months. On the morning of May 10, the Moon's apparent size was too small to completely cover the Sun though, revealing a "ring of fire" along the central path of the annular solar eclipse. Near mid-eclipse from Coen, Australia, a webcast team captured this telescopic snapshot of the annular phase. Taken with a hydrogen-alpha filter, the dramatic image finds the Moon's silhouette just within the solar disk, and the limb of the active Sun spiked with solar prominences. Still, after hosting back-to-back solar eclipses, northern Australia will miss the next and final solar eclipse of 2013. This November, a rare hybrid eclipse will track across the North Atlantic and equatorial Africa.
Messier 77 Face-on spiral galaxy M77 lies a mere 47 million light-years away toward the aquatic constellation Cetus. At that estimated distance, the gorgeous island universe is about 100 thousand light-years across. Also known as NGC 1068, its compact and very bright core is well studied by astronomers exploring the mysteries of supermassive black holes in active Seyfert galaxies. M77 is also seen at x-ray, ultraviolet, infrared, and radio wavelengths. But this sharp visible light image based on Hubble data follows its winding spiral arms traced by obscuring dust clouds and red-tinted star forming regions close in to the galaxy's luminous core.
Ring of Fire over Monument Valley As the New Moon continues this season's celestial shadow play, an annular solar eclipse track begins in western Australia at 22:30 UT on May 9 -- near sunrise on May 10 local time. Because the eclipse occurs within a few days of lunar apogee, the Moon's silhouette does not quite cover the Sun during mid-eclipse, momentarily creating a spectacular ring of fire. While a larger region witnesses a partial eclipse, the annular mid-eclipse phase is visible along a shadow track only about 200 kilometers wide but 13,000 kilometers long, extending across the central Pacific. For given locations along it, the ring of fire lasts from 4 to 6 minutes. Near the horizon, the appearance of the May 9/10 annular eclipse (online viewing) is suggested by this dramatic composite from May of 2012. The timelapse sequence depicts an annular eclipse in progress before sunset over Monument Valley in the southwestern United States.