A Path North

What happens if you keep going north? The direction north on the Earth, the place on your horizon below the northern spin pole of the Earth — around which other stars appear to slowly swirl, will remain the same. This spin-pole-of-the-north will never move from its fixed location on the sky — night or day — and its height will always match your latitude. The further north you go, the higher the north spin pole will appear. Eventually, if you can reach the Earth’s North Pole, the stars will circle a point directly over your head. Pictured, a four-hour long stack of images shows stars trailing in circles around this north celestial pole. The bright star near the north celestial pole is Polaris, known as the North Star. The bright path was created by the astrophotographer’s headlamp as he zigzagged up a hill just over a week ago in Lower Saxony, Germany. The astrophotographer can be seen, at times, in shadow. Actually, the Earth has two spin poles — and much the same would happen if you started below the Earth’s equator and went south. via NASA https://ift.tt/39Pcoej

NGC 1672: Barred Spiral Galaxy from Hubble

Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a modest central bar. Prominently barred spiral galaxy NGC 1672, featured here, was captured in spectacular detail in an image taken by the orbiting Hubble Space Telescope. Visible are dark filamentary dust lanes, young clusters of bright blue stars, red emission nebulas of glowing hydrogen gas, a long bright bar of stars across the center, and a bright active nucleus that likely houses a supermassive black hole. Light takes about 60 million years to reach us from NGC 1672, which spans about 75,000 light years across. NGC 1672, which appears toward the constellation of the Dolphinfish (Dorado), has been studied to find out how a spiral bar contributes to star formation in a galaxy’s central regions. via NASA https://ift.tt/2ReQoTH

Color the Universe

Wouldn’t it be fun to color in the universe? If you think so, please accept this famous astronomical illustration as a preliminary substitute. You, your friends, your parents or children, can print it out or even color it digitally. While coloring, you might be interested to know that even though this illustration has appeared in numerous places over the past 100 years, the actual artist remains unknown. Furthermore, the work has no accepted name — can you think of a good one? The illustration, first appearing in a book by Camille Flammarion in 1888, is used frequently to show that humanity’s present concepts are susceptible to being supplanted by greater truths. via NASA https://ift.tt/2Xb30Pe

Venus and the Sisters

After wandering about as far from the Sun on the sky as Venus can get, the brilliant evening star is crossing paths with the sister stars of the Pleiades cluster. Look west after sunset and you can share the ongoing conjunction with skygazers around the world. Taken on April 2, this celestial group photo captures the view from Portal, Arizona, USA. Even bright naked-eye Pleiades stars prove to be much fainter than Venus though. Apparent in deeper telescopic images, the cluster’s dusty surroundings and familiar bluish reflection nebulae aren’t quite visible, while brighter Venus itself is almost overwhelming in the single exposure. And while Venus and the Sisters do look a little star-crossed, their spiky appearance is the diffraction pattern caused by multiple leaves in the aperture of the telephoto lens. The last similar conjunction of Venus and Pleiades occurred nearly 8 years ago. via NASA https://ift.tt/3dMwOYm

The Traffic in Taurus

There’s a traffic jam in Taurus lately. On April 1, this celestial frame from slightly hazy skies over Tapiobicske, Hungary recorded an impressive pile up toward the zodiacal constellation of the Bull and the Solar System’s ecliptic plane. Streaking right to left the International Space Station speeds across the bottom of the telescopic field of view. Wandering about as far from the Sun in planet Earth’s skies as it can get, inner planet Venus is bright and approaching much slower, overexposed at the right. Bystanding at the upper left are the sister stars of the Pleiades. No one has been injured in the close encounter though, because it really isn’t very close. Continuously occupied since November 2000, the space station orbits some 400 kilometers above the planet’s surface. Venus, currently the brilliant evening star, is almost 2/3 of an astronomical unit away. A more permanent resident of Taurus, the Pleiades star cluster is 400 light-years distant. via NASA https://ift.tt/2UXr6ub

Venus and the Pleiades in April

Venus is currently the brilliant evening star. Shared around world, in tonight’s sky Venus will begin to wander across the face of the lovely Pleiades star cluster. This digital sky map illustrates the path of the inner planet as the beautiful conjunction evolves, showing its position on the sky over the next few days. The field of view shown is appropriate for binocular equipped skygazers but the star cluster and planet are easily seen with the naked-eye. As viewed from our fair planet, Venus passed in front of the stars of the Seven Sisters 8 years ago, and will again 8 years hence. In fact, orbiting the Sun 13 Venus years are almost equal to 8 years on planet Earth. So we can expect our sister planet to visit nearly the same place in our sky every 8 years. via NASA https://ift.tt/39y8sy7

Asteroid or Potato

Is this asteroid Arrokoth or a potato? Perhaps, after all the data was beamed back to Earth from NASA’s robotic New Horizons spacecraft, the featured high resolution image of asteroid Arrokoth was constructed. Perhaps, alternatively, the featured image is of a potato. Let’s consider some facts. Arrokoth is the most distant asteroid ever visited and a surviving remnant of the early years of our Solar System. A potato is a root vegetable that you can eat. Happy April Fool’s Day from the folks at APOD! Although asteroid Arrokoth may look like a potato, in fact very much like the featured potato, Arrokoth (formerly known as Ultima Thule) is about 200,000 times wider and much harder to eat. via NASA https://ift.tt/2UQHooB

The Galactic Center from Radio to X ray

In how many ways does the center of our Galaxy glow? This enigmatic region, about 26,000 light years away toward the constellation of the Archer (Sagittarius), glows in every type of light that we can see. In the featured image, high-energy X-ray emission captured by NASA’s orbiting Chandra X-Ray Observatory appears in green and blue, while low-energy radio emission captured by SARAO’s ground-based MeerKAT telescope array is colored red. Just on the right of the colorful central region lies Sagittarius A (Sag A), a strong radio source that coincides with Sag A*, our Galaxy’s central supermassive black hole. Hot gas surrounds Sag A, as well as a series of parallel radio filaments known as the Arc, seen just left of the image center. Numerous unusual single radio filaments are visible around the image. Many stars orbit in and around Sag A, as well as numerous small black holes and dense stellar cores known as neutron stars and white dwarfs. The Milky Way’s central supermassive black hole is currently being imaged by the Event Horizon Telescope. via NASA https://ift.tt/2QY1fBk

The Colors of Saturn from Cassini

What creates Saturn’s colors? The featured picture of Saturn only slightly exaggerates what a human would see if hovering close to the giant ringed world. The image was taken in 2005 by the robot Cassini spacecraft that orbited Saturn from 2004 to 2017. Here Saturn’s majestic rings appear directly only as a curved line, appearing brown, in part, from its infrared glow. The rings best show their complex structure in the dark shadows they create across the upper part of the planet. The northern hemisphere of Saturn can appear partly blue for the same reason that Earth’s skies can appear blue — molecules in the cloudless portions of both planet’s atmospheres are better at scattering blue light than red. When looking deep into Saturn’s clouds, however, the natural gold hue of Saturn’s clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue — one hypothesis holds that clouds are higher there. It is also not known why some of Saturn’s clouds are colored gold. via NASA https://ift.tt/3dOhoD8

A 212 Hour Exposure of Orion

The constellation of Orion is much more than three stars in a row. It is a direction in space that is rich with impressive nebulas. To better appreciate this well-known swath of sky, an extremely long exposure was taken over many clear nights in 2013 and 2014. After 212 hours of camera time and an additional year of processing, the featured 1400-exposure collage spanning over 40 times the angular diameter of the Moon emerged. Of the many interesting details that have become visible, one that particularly draws the eye is Barnard’s Loop, the bright red circular filament arcing down from the middle. The Rosette Nebula is not the giant red nebula near the top of the image — that is a larger but lesser known nebula known as Lambda Orionis. The Rosette Nebula is visible, though: it is the red and white nebula on the upper left. The bright orange star just above the frame center is Betelgeuse, while the bright blue star on the lower right is Rigel. Other famous nebulas visible include the Witch Head Nebula, the Flame Nebula, the Fox Fur Nebula, and, if you know just where to look, the comparatively small Horsehead Nebula. About those famous three stars that cross the belt of Orion the Hunter — in this busy frame they can be hard to locate, but a discerning eye will find them just below and to the right of the image center. via NASA https://ift.tt/3apIyhm