Great Orion Nebulae - 2008-10-23

The Great Nebula in Orion, also known as M42, is one of the most famous nebulae in the sky. The star forming region's glowing gas clouds and hot young stars are on the right in this sharp and colorful two frame mosaic that includes the smaller nebula M43 near center and dusty, bluish reflection nebulae NGC 1977 and friends on the left. Located at the edge of an otherwise invisible giant molecular cloud complex, these eye-catching nebulae represent only a small fraction of this galactic neighborhood's wealth of interstellar material. Within the well-studied stellar nursery, astronomers have also identified what appear to be numerous infant solar systems. The gorgeous skyscape spans nearly two degrees or about 45 light-years at the Orion Nebula's estimated distance of 1,500 light-years. Editor's Note: A version of the image with labels generated by Astrometry.net is available here.  

IC 4406: A Seemingly Square Nebula - 2002-06-18

How can a round star make a square nebula? This conundrum comes to light when studying planetary nebulae like IC 4406. Evidence indicates that IC 4406 is likely a hollow cylinder, with its square appearance the result of our vantage point in viewing the cylinder from the side. Were IC 4406 viewed from the top, it would likely look similar to the Ring Nebula. This representative-color picture is a composite made by combining images taken by the Hubble Space Telescope last June and this January. Hot gas flows out the ends of the cylinder, while filaments of dark dust and molecular gas lace the bounding walls. The star primarily responsible for this interstellar sculpture can be found in the planetary nebula's center. In a few million years, the only thing left visible in IC 4406 will be a fading white dwarf star.  

Analemma over Ancient Nemea - 2004-06-21

An analemma is that figure-8 curve that you get when you mark the position of the Sun at the same time each day throughout planet Earth's year. Above, 44 separate exposures (plus one foreground exposure) were recorded on a single piece of film to illustrate the regular solar motion -- a Herculean task performed during the calendar year 2003. Appropriately, in the foreground are the ruins at Ancient Nemea where the hero of Greek Mythology pursued the first of his twelve labours. Solstices, like the one that occurred at 0057 UT on June 21, correspond to the top and bottom of the figure-8 or the northern and southernmost excursions of the Sun in the sky. The tilt of planet Earth's axis and the variation in speed as it moves around its orbit combine to produce the graceful analemma curve.  

Stars and Dust across Corona Australis - 2023-06-22

Cosmic dust clouds cross a rich field of stars in this telescopic vista near the northern boundary of Corona Australis, the Southern Crown. Part of a sprawling molecular cloud complex this star forming region is a mere 500 light-years away. That's about one third the distance of the more famous stellar nursery known as the Orion Nebula. The 2 degree wide frame would span 15 light-years at the clouds' estimated distance. Mixed with bright nebulosities the dust clouds effectively block light from more distant background stars in the Milky Way and obscure from view embedded stars still in the process of formation. Large dark nebula Bernes 157 is on the left. To its right are a group of pretty reflection nebulae cataloged as NGC 6726, 6727, 6729, and IC 4812. Their characteristic blue color is produced as light from hot stars is reflected by the cosmic dust. The more compact NGC 6729 surrounds young variable star R Coronae Australis. Just below it, filamentary arcs and loops are identified as Herbig Haro objects associated with energetic newborn stars. In fact, at the heart of this area lies the Coronet Cluster, one of the nearest and most active star forming regions.  

Herschel's Andromeda - 2013-02-02

This infrared view from the Herschel Space Observatory explores the Andromeda Galaxy, the closest large spiral galaxy to our own Milky Way. Only 2.5 million light-years distant, the famous island universe is also known to astronomers as M31. Andromeda spans over 200,000 light-years making it more than twice the size of the Milky Way. Shown in false color, the image data reveal the cool dust lanes and clouds that still shine in the infrared but are otherwise dark and opaque at visual wavelengths. Red hues near the galaxy's outskirts represent the glow of dust heated by starlight to a few tens of degrees above absolute zero. Blue colors correspond to hotter dust warmed by stars in the more crowded central core. Also a tracer of molecular gas, the dust highlights Andromeda's prodigious reservoir of raw material for future star formation.