Orion over the Central Bohemian Highlands

Do you recognize this constellation? Setting past the Central Bohemian Highlands in the Czech Republic is Orion, one of the most identifiable star groupings on the sky and an icon familiar to humanity for over 30,000 years. Orion has looked pretty much the same during this time and should continue to look the same for many thousands of years into the future. Prominent Orion is high in the sky at sunset this time of year, a recurring sign of (modern) winter in Earth’s northern hemisphere and summer in the south. The featured picture is a composite of over thirty images taken from the same location and during the same night last month. Below and slightly to the left of Orion’s three-star belt is the Orion Nebula, while four of the bright stars surrounding the belt are, clockwise, Sirius (far left, blue), Betelgeuse (top, orange, unusually faint), Aldebaran (far right), and Rigel (below). As future weeks progress, Orion will set increasingly earlier. via NASA https://ift.tt/37DuONK

The Changing Surface of Fading Betelgeuse

Besides fading, is Betelgeuse changing its appearance? Yes. The famous red supergiant star in the familiar constellation of Orion is so large that telescopes on Earth can actually resolve its surface — although just barely. The two featured images taken with the European Southern Observatory’s Very Large Telescope show how the star’s surface appeared during the beginning and end of last year. The earlier image shows Betelgeuse having a much more uniform brightness than the later one, while the lower half of Betelgeuse became significantly dimmer than the top. Now during the first five months of 2019 amateur observations show Betelgeuse actually got slightly brighter, while in the last five months the star dimmed dramatically. Such variability is likely just normal behavior for this famously variable supergiant, but the recent dimming has rekindled discussion on how long it may be before Betelgeuse does go supernova. Since Betelgeuse is about 700 light years away, its eventual supernova — probably thousands of years in the future — will likely be an amazing night-sky spectacle, but will not endanger life on Earth. via NASA https://ift.tt/2u2NbxV

NGC 2392: Double Shelled Planetary Nebula

To some, this huge nebula resembles a person’s head surrounded by a parka hood. In 1787, astronomer William Herschel discovered this unusual planetary nebula: NGC 2392. More recently, the Hubble Space Telescope imaged the nebula in visible light, while the nebula was also imaged in X-rays by the Chandra X-ray Observatory. The featured combined visible-X ray image, shows X-rays emitted by central hot gas in pink. The nebula displays gas clouds so complex they are not fully understood. NGC 2392 is a double-shelled planetary nebula, with the more distant gas having composed the outer layers of a Sun-like star only 10,000 years ago. The outer shell contains unusual light-year long orange filaments. The inner filaments visible are being ejected by strong wind of particles from the central star. The NGC 2392 Nebula spans about 1/3 of a light year and lies in our Milky Way Galaxy, about 3,000 light years distant, toward the constellation of the Twins (Gemini). via NASA https://ift.tt/2Sua1rG

Carina Nebula Close Up

A jewel of the southern sky, the Great Carina Nebula, also known as NGC 3372, spans over 300 light-years, one of our galaxy’s largest star forming regions. Like the smaller, more northerly Great Orion Nebula, the Carina Nebula is easily visible to the unaided eye, though at a distance of 7,500 light-years it is some 5 times farther away. This gorgeous telescopic close-up reveals remarkable details of the region’s central glowing filaments of interstellar gas and obscuring cosmic dust clouds in a field of view nearly 20 light-years across. The Carina Nebula is home to young, extremely massive stars, including the still enigmatic and violently variable Eta Carinae, a star system with well over 100 times the mass of the Sun. In the processed composite of space and ground-based image data a dusty, two-lobed Homunculus Nebula appears to surround Eta Carinae itself just below and left of center. While Eta Carinae is likely on the verge of a supernova explosion, X-ray images indicate that the Great Carina Nebula has been a veritable supernova factory. via NASA https://ift.tt/31XTOhq

The Pale Blue Dot

On Valentine’s Day in 1990, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back one last time to make the first ever Solar System family portrait. The portrait consists of the Sun and six planets in a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane. Planet Earth was captured within a single pixel in this single frame. It’s the pale blue dot within the sunbeam just right of center in this reprocessed version of the now famous view from Voyager. Astronomer Carl Sagan originated the idea of using Voyager’s camera to look back toward home from a distant perspective. Thirty years later, on this Valentine’s day, look again at the pale blue dot. via NASA https://ift.tt/38rKipw

Spitzer s Trifid

The Trifid Nebula, also known as Messier 20, is easy to find with a small telescope. About 30 light-years across and 5,500 light-years distant it’s a popular stop for cosmic tourists in the nebula rich constellation Sagittarius. As its name suggests, visible light pictures show the nebula divided into three parts by dark, obscuring dust lanes. But this penetrating infrared image reveals the Trifid’s filaments of glowing dust clouds and newborn stars. The spectacular false-color view is courtesy of the Spitzer Space Telescope. Astronomers have used the infrared image data to count newborn and embryonic stars which otherwise can lie hidden in the natal dust and gas clouds of this intriguing stellar nursery. Launched in 2003, Spitzer explored the infrared Universe from an Earth-trailing solar orbit until its science operations were brought to a close earlier this year, on January 30. via NASA https://ift.tt/2SkOxNY

Star Trails of the North and South

What divides the north from the south? It all has to do with the spin of the Earth. On Earth’s surface, the equator is the dividing line, but on Earth’s sky, the dividing line is the Celestial Equator — the equator’s projection onto the sky.  You likely can’t see the Earth’s equator around you, but anyone with a clear night sky can find the Celestial Equator by watching stars move.  Just locate the dividing line between stars that arc north and stars that arc south. Were you on Earth’s equator, the Celestial Equator would go straight up and down.  In general, the angle between the Celestial Equator and the vertical is your latitude.  The featured image combines 325 photos taken every 30 seconds over 162 minutes. Taken soon after sunset earlier this month, moonlight illuminates a snowy and desolate scene in northwest Iran. The bright streak behind the lone tree is the planet Venus setting. via NASA https://ift.tt/2ULvIFo

Solar Eclipse over the UAE

What’s happening behind that camel? A partial eclipse of the Sun. About six and a half weeks ago, the Moon passed completely in front of the Sun as seen from a narrow band on the Earth. Despite (surely) many camels being located in this narrow band, only one found itself stationed between this camera, the distant Moon, and the even more distant Sun. To create this impressive superposition, though, took a well-planned trip to the United Arab Emirates, careful alignments, and accurate timings on the day of the eclipse. Although the resulting featured image shows a partially eclipsed Sun rising, the Moon went on to appear completely engulfed by the Sun in an annular eclipse known as a ring of fire. Forward scattering of sunlight, dominated by quantum mechanical diffraction, gives the camel hair and rope fray an unusual glow. The next solar eclipse is also an annular eclipse and will occur this coming June. via NASA https://ift.tt/2OGmExD

To Fly Free in Space

What would it be like to fly free in space? At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was living the dream — floating farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured, was floating free in space. McCandless and fellow NASA astronaut Robert Stewart were the first to experience such an « untethered space walk » during Space Shuttle mission 41-B in 1984. The MMU worked by shooting jets of nitrogen and was used to help deploy and retrieve satellites. With a mass over 140 kilograms, an MMU is heavy on Earth, but, like everything, is weightless when drifting in orbit. The MMU was later replaced with the SAFER backpack propulsion unit. via NASA https://ift.tt/2HbtpDe

NGC 7331 Close Up

Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier’s famous 18th century catalog. Since the galaxy’s disk is inclined to our line-of-sight, long telescopic exposures often result in an image that evokes a strong sense of depth. In this Hubble Space Telescope close-up, the galaxy’s magnificent spiral arms feature dark obscuring dust lanes, bright bluish clusters of massive young stars, and the telltale reddish glow of active star forming regions. The bright yellowish central regions harbor populations of older, cooler stars. Like the Milky Way, a supermassive black hole lies at the core of spiral galaxy NGC 7331. via NASA https://ift.tt/2H0rvVY