Andromeda in a Single Shot - 2021-06-25

How far can you see? The Andromeda Galaxy, 2.5 million light years away, is the most distant object easily seen by the unaided eye. Other denizens of the night sky, like stars, clusters, and nebulae, are typically hundreds to thousands of light-years distant. That's far beyond the Solar System but well within our own Milky Way Galaxy. Also known as M31, the external galaxy poses directly above a chimney in this well-planned deep night skyscape from an old mine in southern Portugal. The image was captured in a single exposure tracking the sky, so the foreground is slightly blurred by the camera's motion while Andromeda itself looms large. The galaxy's brighter central region, normally all that's visible to the naked-eye, can be seen extending to spiral arms with fainter outer reaches spanning over 4 full moons across the sky. Of course in only 5 billion years or so, the stars of Andromeda could span the entire night sky as the Andromeda Galaxy merges with the Milky Way.  

Aurora Over New Zealand - 2001-04-06

Last weekend skygazers at middle and high latitudes around the globe were treated to expansive auroral displays as a magnetic storm raged around planet Earth. The storm was triggered by a solar coronal mass ejection associated with the giant sunspot group cataloged as active region number 9393. For example, pictured here in the early morning hours of April 1, the skies over New Zealand are alive with "southern lights". In the wide-angle time exposure, a towering red aurora is visible suspended above the foreground of a well lit lumber yard, train station, church steeple and buildings of the city of Dunedin. On April 2, the largest solar flare of the last 25 years also erupted near active region 9393, but because of its position near the Sun's edge the effects were largely directed away from our fair planet. However, all the recent solar activity underscores the fact that the solar maximum is still with us.  

M17: The Omega Nebula - 1999-01-26

The Omega Nebula contains glowing gas, dark dust, and some unusually massive stars. Also known as the M17 and the Swan Nebula, the Omega Nebula is about 5000 light-years away, 20 light-years across, and visible with binoculars in the constellation of Sagittarius. A recent epoch of star formation has created some very massive stars that haven't yet had time to self-destruct. Until then, these stars appear very bright and emit light so energetic it breaks up the surrounding gas and dust. The streaks across the bright stars are blemishes caused by the digital camera.  

Martian Chiaroscuro - 2014-03-22

Deep shadows create dramatic contrasts between light and dark in this high-resolution close-up of the martian surface. Recorded on January 24 by the HiRISE camera onboard the Mars Reconnaissance Orbiter, the scene spans about 1.5 kilometers across a sand dune field in a southern highlands crater. Captured when the Sun was just 5 degrees above the local horizon, only the dune crests are caught in full sunlight. With the long, cold winter approaching the red planet's southern hemisphere, bright ridges of seasonal frost line the martian dunes.  

RCW 86: Historical Supernova Remnant - 2022-05-28

In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest recorded supernova. This deep image shows emission nebula RCW 86, understood to be the remnant of that stellar explosion. The narrowband data trace gas ionized by the still expanding shock wave. Space-based images indicate an abundance of the element iron and lack of a neutron star or pulsar in the remnant, suggesting that the original supernova was Type Ia. Unlike the core collapse supernova explosion of a massive star, a Type Ia supernova is a thermonuclear detonation on a a white dwarf star that accretes material from a companion in a binary star system. Near the plane of our Milky Way galaxy and larger than a full moon on the sky this supernova remnant is too faint to be seen by eye though. RCW 86 is some 8,000 light-years distant and around 100 light-years across.