Title:[0534] A Group of Bok globules seen against IC 2944 Caption:Against the uniform, bright backdrop of IC 2944 we see a small group of dark clouds of the kind known as "Bok globules." They are named for the Dutch-American astronomer who first drew attention to them as the possible sites of star formation. These dark markings are discrete, opaque dust clouds, the largest containing enough material to form several stars the mass of the Sun. The globules are not some line-of-sight coincidence; the brightened rim of the largest clearly shows it to be associated with the nebulosity of IC 2944. Bok globules are yet another manifestation of the interaction of dust clouds with energetic radiation from hot stars. Copyright:(c) 1992 Anglo-Australian Telescope Board, photograph by David Malin Credit:

Title:[0923] Sharpless 171, star formation in Milky Way Caption:Sharpless 171, star formation in Milky Way Copyright: Credit: National Optical Astronomy Observatories

Title:[0925] Solar-type star forming in Barnard 5 cloud Caption:Solar-type star forming in Barnard 5 cloud Copyright: Credit:National Optical Astronomy Observatories

Title:[0930] Star formation region in Orion constellation Caption:Star formation region in Orion constellation Copyright: Credit:National Optical Astronomy Observatories

Title:[0238] The stars that excite the Trifid Nebula Caption:Surrounding the central stars in the famous Trifid Nebula (M20) is a cloud of patchy dust and gas. Though dust and gas are common throughout the Milky Way, the gas itself can only be seen at visible wavelengths when it is illuminated by stars whose output of ultraviolet light is sufficient to cause it to glow with the red color characteristic of hydrogen. Such hot stars are found at the heart of the Trifid Nebula, and they illuminate a gas cloud against which the dust lanes can be seen. This nebula is at a distance of about 3,000 light years. Copyright:(c) 1982 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0237] The Trapezium stars in the Orion Nebula Caption:In the nearby Orion nebula are some of the youngest stars known, and though many are still hidden from view, the brightest form a group that can be seen with binoculars. They make up the central "star" of the three groups, forming the sword-handle of Orion. This group is known as the Trapezium cluster and they provide much of the energy which makes the brilliant Orion Nebula visible. The nebula and its clutch of young stars are at a distance of about 1,300 light years. Copyright:(c) 1981 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0249] Reddened nebulosity in NGC 3603 Caption:The distant cluster NGC 3603 is unusual in that it is a young group where the stars are remarkably close together. Moreover, many of the stars in this compact constellation are Wolf-Rayet stars: extremely hot, massive objects, rarely found in such profusion in clusters. This curious collection of young objects is as far as we know unique in our galaxy - though the enigmatic object at the center of the Tarantula Nebula in the Large Magellanic Cloud may be a similarly compact, though much richer, cluster. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit: D. F. Malin

Title:[0245] A reflection nebula in Orion, NGC 1977 Caption:This scattered cluster of nebulous stars is just half a degree north of the much more spectacular Orion Nebula and because of this has been largely ignored. The group of stars here is visible to the unaided eye as a single object, the northernmost "star" in the sword-handle of Orion. Most of the blue nebulosity is starlight scattered by dust, while some stars are sufficiently hot to excite wisps of hydrogen that pervade the region. These colors combine to make magenta, and create a distinctive and unusual nebula, quite unlike the adjacent Orion nebula. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0261] Antares and the Rho Ophiuchi dark cloud Caption:The dusty region between Ophiuchus and Scorpius contains some of the most colorful and spectacular nebulae ever photographed. The upper part of the picture is filled with the bluish glow of reflected light from hot stars near a huge, cool cloud of dust and gas where stars are born. Dominating the lower half of the picture is an over-exposed image of the red supergiant star Antares, a star that is steadily shedding material from its distended surface as it nears the end of its life. These solid particles reflect Antares' light and hide it in a nebula of its own making. Finally, partly surrounding Sigma Scorpii at the left of the picture is a red emission nebula, completing the most comprehensive collection of nebular types ever seen in one photograph. Copyright:(c) ROE/Anglo-Australian Telescope Board, photographs by David Malin Credit:D. F. Malin

Title:[0247] The Carina nebula and Trumpler 14 Caption:In the small region pictured here are three of the most luminous stars known in our Galaxy, each brighter than a million sun-like stars. To the left of the picture is an even more extreme star, Eta Carinae, shrouded in a small bright irregular nebula. In the upper right of the photograph is a cluster of very young stars, which appears to be associated with a number of bright-edged "elephant trunk" dust lanes, typical of many star-forming regions. All these objects and most of the bright stars scattered across the face of the nebula are together in space at a distance of about 7,000 light years. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0241] The Cone nebula in the NGC 2264 cluster Caption:The Cone nebula is the visible part of a large cloud of hydrogen and tiny solid particles in the constellation of Monoceros. Within and around this cloud are many recently formed stars, some completely hidden within the dense interstellar matter. They can be detected by special infra-red techniques that are able to penetrate the obscuration. The largest of the dust clouds is in the foreground; it is this curious straight-sided feature that gives the object its name. Copyright:(c) 1981 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0531] Corona Australis reflection nebula, NGC 6726-7 Caption:This spectacular reflection nebula is the result of a few bright stars caught up in a large, dusty cloud. The peculiar yellowish curved streak near the two bright reflection nebulae seems to be the source of two compact but distinctly red patches, which are Herbig-Haro objects, often the first visible signs of star formation occurring deep inside dark clouds. These compact nebulae are ejected from proto-stars during the later stages of star formation and sometimes appear in pairs, moving in opposite directions from the hidden star-forming region. Copyright:(c) 1992 Anglo-Australian Telescope Board, photograph by David Malin Credit:

Title:[0252] The dust lanes in Messier 16 Caption:There are few clearer examples anywhere of the intimate relationship between dust, gas and young stars than M16. We see a young cluster of stars (NGC 6611), which formed about 2 million years ago, illuminating a cloud of hydrogen gas. The glowing hydrogen provides a vivid background against which are seen numerous dark lanes and discrete globules of dust. Many of the dusty clouds are edged with bright rims, which indicate the direction of the exciting stars and point to the cluster as the energizing source. Copyright:(c) 1986 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[1118] Eagle Nebula in Serpens Caption:Eagle Nebula, M16, NGC 6611; an irregular, gaseous nebula in the constellation Serpens. The many bright-edged features visible are shock fronts between gas clouds in different states of ionization. The dark areas consist of opaque dust and gas. Kitt Peak 4-meter Mayall telescope photograph. Copyright: Credit:National Optical Astronomy Observatories

Title:[0107] The Emission Nebula in Messier 16, NGC 6611 Caption:M16 is a typical star-forming region. Within it has appeared a cluster of young stars, which formed about 2 million years ago, among them a few very massive hot stars. Brilliant stars of this type are much hotter than the Sun and are often thirty times more massive. The dark intrusions visible across the face of the nebula are thought to be condensations of dusty material that might one day collapse into yet more stars. Bright red regions of photo-ionized hydrogen such as M16 are usually found in the spiral arms of galaxies and are often associated with dust. Copyright:(c) 1980 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0590] Eta Carinae Caption:The Carina nebula is one of the brightest optical emission nebulae in the Milky Way. It stretches over some 2-1/2 degrees of sky which, at a distance of 2.6 kpc (8,000 light years), is 300 light years across - about twenty times the size of the Orion nebula. Two clusters of young stars are primarily responsible for heating the nebula. Each cluster contains one of the brightest known stars in our galaxy. One is HD93129 A, which has a mass estimated to be about 120 times that of the Sun and releases most of its five million solar luminosities as ultraviolet radiation. The second bright star is Eta Carinae. Eta Carinae, which also is one of the most luminous stars in our galaxy with a bolometric or total luminosity exceeding 10 40 ergs/sec, emits most of its energy in the infrared. Eta Carinae is today the brightest infrared source outside our solar system observed at wavelengths of 10 and 20 microns. At about 7th magnitude, Eta Carinae is not visible to the naked eye today, but the star's brightness has changed by large amounts over the centuries. Halley estimated it to be 4 times the magnitude observed in 1977. About one hundred years later it was observed to be two magnitudes brighter. During the mid-1840s, it had brightened to magnitude -1 and was the second brightest star in the sky! Eta Carinae remained brighter than first magnitude until 1857, then faded to magnitude 8 by 1900. However, by the late 1970s, it had brightened to magnitude 6.2. It continues to show slow changes in its brightness. Copyright:(c) Smithsonian Astrophysical Observatory Credit:Courtesy of National Optical Astronomy Observatories

Title:[0243] Eta Carinae and the Keyhole Nebula Caption:This nebula was first sketched and described in detail by Sir John Herschel in 1838. He noted the circular shell visible in the upper part of the picture extending to the south to form a keyhole-shaped nebula. This southern outline is no longer bright and appears only as a dark dust cloud. It seems that in the years since Herschel's observations, the curious variable star Eta Carinae, to the left of the dust cloud, has buried itself in a cocoon of dust that it ejected, and light from the star is no longer able to illuminate the rim of the "keyhole." Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0591] Eta Carinae: infrared image Caption:Total luminosity of Eta Carinae (for a distance of 2,600 pc) is ~6 x 10-6 times that of the Sun. The infrared emission arises predominantly from a shell of dust apparently associated with the "Homunculus nebula" around it. The dust is heated by the central star to a temperature of ~250 K. The present infrared luminosity is the same as the maximum optical luminosity observed in the outburst in 1843. The size of this region, 12' x 17', is too small to be resolved by IRAS, but could be studied in detail by SIRTF. Copyright:(c) Smithsonian Astrophysical Observatory Credit:Courtesy of JPL/IPAC2

Title:[1094] Eta Carinae or Keyhole Nebula in Carina Caption:Eta Carinae Nebula, NGC 3372, also called Keyhole Nebula, in the constellation Carina. This gaseous bright nebula surrounds the peculiar variable star Eta Carina, with overlying clouds of dark material. The nebula is 8,000 light years from Earth. CTIO photograph. Copyright: Credit:National Optical Astronomy Observatories

Title:[1153] Eta Carinae or Keyhole Nebula in Carina Caption:Central portion of the Eta Carinae Nebula, NGC 3372, also "Keyhole Nebula," in the constellation Carina. This gaseous bright nebula surrounds the peculiar variable star Eta Carinae, with overlying clouds of dark material. Cerro Tololo Inter-American Observatory 4-meter telescope photo. The nebula is 8,000 light years from Earth. Copyright: Credit:National Optical Astronomy Observatories

Title:[0276] Faint Nebulosity near Orion and Horsehead Nebula Caption:This wide-angle picture of the Orion region has been made to reveal the extensive network of very faint filaments that are traceable over most of the constellation. These faint features are optical evidence of a substantial dark cloud of molecular gas and dust, which dominate at radio wavelengths. Where hot stars are closely associated with the molecular cloud, a nebula appears. By far the brightest of these is the Orion Nebula, M42. This spectacular object is so bright that its light is reflected from filaments of the dark cloud some distance away. In contrast, the wisps of the Horsehead Nebula are much fainter but even here faint tendrils of nebulosity show that the nebula is much more extensive than is generally realized. Copyright:(c) 1987 Royal Observatory Edinburgh Credit:D. F. Malin

Title:[0262] The Great Nebula in Carina, NGC 3372 Caption:Although no bright naked-eye stars are associated with the Carina Nebula now, 150 years ago there blazed forth here one of the most unusual and peculiar stars ever seen. The star is known as Eta Carinae and for a few months in 1843 it was the second or third brightest star in the sky. Since then it has faded and is today about 1,000 times fainter than it was at its brightest. The whole region around Eta Carinae is rich in hot stars of which Eta is an extreme example and it is their combined radiation that produces the spectacular Carina Nebula, which dominates this picture. Copyright:(c) ROE/Anglo-Australian Telescope Board, photographs by David Malin Credit:D. F. Malin

Title:[0251] Homunculus Nebula around Eta Carinae Caption:Eta Carinae is a very unusual variable star. In 1834, Sir John Herschel saw it as one of the brightest in the sky but within a few years it had faded and was no longer visible without a telescope. The sudden brightening of the star was the result of a massive explosion that ejected a substantial shell of material from its surface. As it expanded, the star seemed to brighten until the luminous shell itself cooled, dimmed and finally became opaque, hiding the light of the star inside. 150 years after Herschel's observations, we now see the shell as a tiny, orange-red manikin-shaped nebula. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0142] The Horsehead Nebula and NGC 2024 Caption:This well-known dark nebula is one of the best-known images in astronomy, probably because of its chance likeness to the head of a horse. The distinctive outline is an extension of a substantial cloud of dark obscuring material filling the lower part of the picture; it hides the light of stars beyond. The outer surface of the dusty gas is illuminated by a bright star off the top of the picture which causes the gas there to glow, silhouetting the horsehead shape. A bright star is partially enveloped in the dust cloud and its scattered light is seen as a blue reflection nebula. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0258] The Horsehead Nebula and NGC 2024 in Orion Caption:This distinctive red emission nebula is the result of radiation from Sigma Orionis interacting with the surface of a dusty cloud of gas from which projects the dark shape of the head of a horse. Sigma is the second brightest star in the picture and is at about the same distance from the Sun as the nebula. The brightest star here is Zeta Orionis, easily visible to the unaided eye as the easternmost star in the line of three that form Orion's Belt. Partly obscured by the glare of Zeta is the curious yellowish nebula NGC 2024, whose energy comes from a star hidden in the dark lane, while other nebulae simply reflect the light of embedded hot stars and appear blue. Copyright:(c) 1979 ROE/Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[1122] Horsehead Nebula in Orion Caption:The Horsehead Nebula in Orion, part of IC 434. This Kitt Peak National Observatory 4-meter photograph shows the cloud of opaque dust that absorbs light from stars beyond it, creating this unusual formation. The Horsehead is 1,600 light years away from us. Copyright: Credit:National Optical Astronomy Observatories

Title:[0242] The Hourglass Nebula in Messier 8 Caption:This extremely bright object, named for its shape, is associated with the blue star alongside it, which was named Herschel 36 after its discoverer. The nebula is energized partly by the bright star and partly by a star which, for the present, remains hidden in the dust that forms the waist of the Hourglass. The obscured star is only detectable in infrared light that penetrates the patchy obscuration in evidence over much of the region, especially against the Lagoon nebula of which the Hourglass is the brightest part. Copyright:(c) 1982 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[1123] Hubble's Variable Nebula in Monoceros Caption:Hubble's Variable Nebula, NGC 2261, in the constellation Monoceros. The reflection nebula is shaped like a comet and lit by a variable star in its "head." Variations in brightness across the nebula are probably due to internal clouds passing between the star and cloud. The nebula is located 2,600 light years away and has a diameter of seven light years. Kitt Peak National Observatory 0.9-meter telescope photograph. Copyright: Credit:National Optical Astronomy Observatories

Title:[1071] Infrared image of NGC 7538 Caption:An infrared image of NGC 7538, a region of massive star formation within our Galaxy. The colors in the infrared image were produced by taking three images through filters at three different wavelengths (1.2, 1.65 and 2.2 microns) and combining them, similar to the method used by color television. NGC 7538 is located about 7,000 light years from Earth. The red object in the lower left is a very young star heavily embedded in the molecular cloud from which it formed; the blue extension to the lower right from this young star is caused by radiation scattered from dust grains within the cloud. The patch of interstellar hydrogen is ionized by ultraviolet radiation from massive young stars. Kitt Peak National Observatory 1.3-meter telescope photo taken by Ian Gatley, 1989. Copyright: Credit:National Optical Astronomy Observatories/Dr. Ian Gatley

Title:[1152] Lagoon nebula in Sagittarius Caption:M8, NGC 6523, the Lagoon Nebula in the constellation Sagittarius. The Lagoon Nebula glows with the red light of hydrogen (H-alpha) excited by the radiation of very hot stars buried within its center. Deep within the cloud, dark filaments of obscuring matter emit strong, infrared radiation. Several peculiar variable stars in the nebula occasionally flare up, increasing in brightness to some 25 times their normal luminosity. The nebula is at a distance of 6,500 light years and has a 60 light year diameter. Kitt Peak 4-meter Mayall telescope photograph. Copyright: Credit:National Optical Astronomy Observatories

Title:[0159] The Lagoon nebula, Messier 8 Caption:The irregular distribution of stars in this part of the sky is due mainly to clouds of dust that dim the light of vast clouds of stars that make Sagittarius one of the brightest parts of the Milky Way. The Lagoon nebula is an illuminated part of such a dark cloud and it reveals the dust as dark lanes and globules silhouetted against the luminous gas. Within the nebula is the young star cluster NGC 6530, though the center of star-forming activity has now shifted westwards from the cluster to the brightest part of the nebula, around the tiny Hourglass Nebula. Copyright:(c) 1979 Royal Observatory Edinburgh Credit:D. F. Malin

Title:[0264] Messier 42, the Great Nebula in Orion Caption:Many other much larger nebulae than M42 in Orion are known, but none offers us so intimate a view of a nearby stellar nursery. To the eye, the nebula appears as a misty patch around the central star of the line of three which form Orion's sword. Binoculars or a modest telescope will show that these three "stars" are loose groups of several individuals some of which can be seen in this photograph. The central group of stars, the Trapezium cluster, is hidden in the glow of the Orion Nebula, but these stars are responsible for producing the nebula. It is the high concentration of dust and gas in this part of the sky that has resulted in the formation of the stars, so the Orion nebula is no random association of bright stars and dusty gas. Copyright:(c) 1982 Royal Observatory Edinburgh Credit:D. F. Malin

Title:[0231] Nebulosity in Sagittarius, NGC 6589-90 Caption:In the direction of the constellation of Sagittarius are huge clouds of interstellar dust. The patchy nature of the obscuration can be seen from the uneven distribution of background stars across this picture. Light from bright stars within the dust produces the two blue reflection nebulae (NGC 6589 and 6590) while a large, almost transparent cloud of hydrogen, mixed with traces of dust, glows with a characteristic magenta hue over most of the field of view. Copyright:(c) 1981 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0093] NGC 3576 and 3603, nebulae in Carina Caption:The apparent intimacy of these two star-forming regions is line-of-sight effect because these two objects are at quite different distances from the Sun. The curious looped nebula NGC 3576 is about 7,000 light years from us while its apparent neighbor NGC 3603 is more than twice as far away. That NGC 3603 is the more distant is confirmed by its color, which is a ruddier red than the pinkish hue of NGC 3576. The change in color is due to absorption of the blue-light component of the nebulosity by dust particles in the much longer line of sight. This effect is known as interstellar reddening, when it is actually the blue light that is affected. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0533] NGC 6188 and the NGC 6193 cluster Caption:The Horsehead Nebula in Orion is widely recognized because it has the distinctive dark outline of the head of a horse, but the mechanisms that created it are seen throughout the Milky Way. Here we see two bright stars whose radiant energy is beating down on to the surface of a dark cloud, very similar to that in Orion. The opacity of the cloud protects the fragile molecules within from the energetic radiation of nearby stars, but as its surface is gradually warmed and eroded, the delicate organic molecules are destroyed and the hydrogen released glows as a distinctive emission nebula. Copyright:(c) 1992 Anglo-Australian Telescope Board, photograph by David Malin Credit:

Title:[0266] NGC 6334 and NGC 6357 in the dust of Scorpius Caption:Most photographs of regions of the nebulae around star-forming regions show that the red nebulosity is associated with one or more very hot, bright stars; these same stars are responsible for the ultra-violet radiation that splits apart hydrogen atoms. In addition to the deep red color, other wavelengths contribute to the overall hue. Most prominent are lines in the blue part of the spectrum and blue light scattered by the dust particles, which are almost always associated with gas clouds in the Galaxy. The normal color of a star-forming region is therefore usually magenta, a bluish-red color, the exact shade depending on the amount of blue light present. The star-forming nebulae NGC 6334 and 6357 show no evidence of a blue component in their color - indeed, the blue-light plate used in this 3-color picture had no nebulous image at all - nor is there any obvious sign of the bright blue stars normally found in these objects. They are excellent examples of the phenomenon known as "interstellar reddening," the selective removal of blue light by minute particles of dust in our line of sight. This accounts for both the ruddy hue and apparent absence of blue stars. The hot stars are present but only some of the red part of their light penetrates the dust in our line of sight and so they are not conspicuous. These nebulae are quite nearby (5,500 light years) but are buried in the dust in the plane of the Milky Way. Careful measurement of the color of stars associated with the nebulae indicate that these objects are dimmed by a factor of about 10 in the green part of the spectrum, much more in the blue region, but relatively little at red wavelengths. Copyright:(c) 1984 Royal Observatory Edinburgh Credit:D. F. Malin

Title:[0260] NGC 6559 and IC 1274-5, nebulosities in Sagittarius Caption:This dusty region is almost certainly associated with the brighter and better-known Lagoon and Trifid Nebulae, which are nearby in the sky. The soft red glow of fluorescent hydrogen is evidence that there are young hot stars associated with the dusty clouds. These bright stars also illuminate the tiny particles, producing blue reflection nebulae bordering some of the emission regions. The dust is also evident in silhouette, both as sinuous dark lanes winding through the luminous gas and as the dark patches obscuring the ancient, yellow stars that populate the central parts of the Milky Way. Copyright:(c) 1979 Royal Observatory Edinburgh Credit:D. F. Malin

Title:[1119] Omega Nebula in Sagittarius Caption:M17, Omega Nebula, Swan Nebula, NGC 6618, in the constellation Sagittarius. A bright nebula with clouds and lanes of opaque dust and gas, M17 is estimated to have a mass 800 times that of our Sun within its 17-light year diameter. This 5,700 light year-distant nebula is a source of radio noise. Kitt Peak National Observatory 4-meter Mayall telescope photo. Copyright: Credit:National Optical Astronomy Observatories

Title:[1068] Omega Nebula (Messier 17) Caption:An infrared color picture of Messier 17, a region of massive star formation located in our Galaxy (the Milky Way) about 7,000 light years from Earth. The color in this infrared picture results from a process in which three images taken through filters at three different wavelengths are combined, similar to the method used by color television. Here the blue, green and red components of the composite represent wavelengths of 1.2, 1.65 and 2.2 microns respectively. The total amount of energy radiated by the stars in Messier 17 is about six million times greater than that radiated by our own Sun. Kitt Peak National Observatory 2.1-meter telescope photo by Ian Gatley, photo made1989. Copyright: Credit:National Optical Astronomy Observatories/Dr. Ian Gatley

Title:[1101] Orion Nebula Caption:Orion Nebula, M42, NGC 1976. A spectacular cloud of gas surrounds several very hot stars in the star cluster deep within the nebula. The nebula's constituent gases include hydrogen, helium, oxygen, carbon, neon, nitrogen, sulfur, argon, and chlorine; the density of these gases is above the critical limit required for stars to form within the nebula. Visible to the unaided eye as the middle star in the "sword" of the constellation Orion, the nebula is located 1,500 light years from Earth. CTIO 4-meter photograph. Copyright: Credit:National Optical Astronomy Observatories

Title:[0579] Omega Nebula: optical image Caption:This optical photograph of the Orion Nebula, taken with the Kitt Peak 4-meter telescope, covers ~1.5 x 1 degrees. At a distance of 1,600 light years and extending 15 light years across, the Orion nebula consists of turbulent ionized gas (60% hydrogen and 38% helium) and dust (2%) heated by the ultraviolet light of hot young stars. The radiation source for the large nebula is the Trapezium, a cluster of four bright stars (with apparent magnitudes from 5.4 to 8.0). The smaller round nebula (M43) to the north of Orion is heated by a single star that shines as brightly as several thousand Suns. The Orion nebula lies at the edge of a large cloud of cold gas and dust, thus small patches of dust obscure part of the radiation from the Orion nebula and appear as dark patches in the optical photograph. A giant molecular cloud of cold material, which lies slightly behind the Orion nebula, is believed to contain newly forming stars. Copyright:(c) Smithsonian Astrophysical Observatory Credit:Courtesy of National Optical Astronomy Observatories

Title:[0582] Orion Constellation region Caption:This false-colour infrared image of the region around the Orion constellation was produced from IRAS observations, and shows a much different view from that seen with optical telescope. The field of this image is ~30 degrees to 40 degrees. The intensity of infrared radiation is represented by colours: "reds" indicate strong 100-micron radiation, and "blues" show strong 12-micron radiation. The shorter wavelength infrared emission is from warmer dust, while the longer-wavelength emission, is from cooler dust. Thus, these observations show not only the intensity of the emission, which corresponds to the amount of dust, but also indicate the temperature of the dust. Copyright: Credit:Courtesy of JPL/IPAC

Title:[0149] The Orion Nebula, M42 and M43 Caption:At a distance of 1,500 light years, the Orion Nebula is the nearest bright nebula to us and can be seen with the naked eye. Its brightness led to it being the first nebula ever photographed (in 1882) and its proximity means that we know more about it than any other star-forming region. The inner regions are glowing mainly in the green light of ionized oxygen, which together with some red emission from hydrogen give the center of the nebula a yellowish color. The energy for this spectacular display comes from the small cluster of stars, the Trapezium, in the brightest part of the nebula and visible in binoculars. Copyright:(c) 1981 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[1181] Red Rectangle nebula Caption:The Red Rectangle Nebula. According to one interpretation, a new solar system may be forming in the waist of the hour-glass shaped nebula, where intense infrared radiation is observed. Kitt Peak National Observatory 4-meter Mayall telescope photograph. Copyright: Credit:National Optical Astronomy Observatories

Title:[0532] The Reflection Nebula in NGC 6188 Caption:Sometimes the dust that hides so much of our galaxy from us forms thin veils or streaks, or, as here, dense clouds, obscuring what is probably a more or less uniform field of faint stars. Such old stars appear slightly yellow on color pictures. The patch of dust that crosses this photograph must be illuminated by energetic radiation from stars that are much hotter than those in the background because hydrogen, which is associated with the dust, has been excited into a vivid red fluorescence by absorbing the invisible ultraviolet light. Copyright:(c) 1992 Anglo-Australian Telescope Board, photograph by David Malin Credit:

Title:[0246] The Rosette Nebula and NGC 2244 Caption:A small group of stars has formed in a large cloud of dusty gas. As their energy penetrates the surrounding material, the cloud begins to disperse, blown away by radiation pressure and intense winds from the surfaces of the hotter (bluer) stars. The hollowed-out center of the Rosette Nebula is about 12 light years across and will expand as the nebula is dispersed, leaving behind NGC 2244, a young cluster of stars. The aptly-named Rosette Nebula is at a distance of about 4,500 light years in the constellation of Monoceros. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0097] S Monocerotis and NGC 2264 Caption:Some of the smallest wispy tendrils seen here are Herbig-Haro objects, jets of matter ejected from newly-formed stars still hidden inside the nebula that fills this picture. The nebula itself is associated with the bright star S Monocerotis and is complex mixture of vivid red hydrogen gas and dark obscuring dust lanes that are typical of star-forming regions. Some dust patches are close enough to bright stars to reflect light from them; these appear blue for the same reason that the daytime sky is blue - because some of the interstellar particles preferentially scatter blue light. Copyright:(c) 1981 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0530] The bright rims of a faint, dark cloud Caption:The shape of the dark cloud is seen where it hides the light of background stars, and is formed by radiation from very luminous stars some distance from the nebula. The direction of the source of radiation can be guessed from the flow pattern in the dark cloud and by noting the extensive bright red rims at the end of the nebula that is exposed to its radiation. This part of the nebula is reminiscent of the famous Horsehead Nebula in Orion, which is also the consequence of starlight destroying a dark cloud. The source of the energy here is the Scorpius OB association, a group of brilliant, very hot stars, about 5,000 light years away from us. Copyright:(c) 1992 Anglo-Australian Telescope Board, photograph by David Malin Credit:

Title:[0529] The head of CG 4, a faint cometary globule Caption:Cometary globules are isolated, relatively small clouds of gas and dust within the Milky Way. The head of the nebula is itself opaque, but glows because it is illuminated by light from very hot stars nearby. Their energy is gradually destroying the dusty head of the globule, sweeping away tiny particles that scatter the starlight as a faint, bluish reflection nebula. This particular globule also shows a faint red glow, probably from excited hydrogen, and seems about to devour an edge-on spiral galaxy, which in reality is millions of light years away, far beyond CG 4. Copyright:(c) 1992 Anglo-Australian Telescope Board, photograph by David Malin Credit:

Title:[0248] The loops of the NGC 3576 nebula Caption:The stars that evidently excite this unusual nebula are not seen on this photograph. They are hidden in the dusty cloud at the base of the huge loops of material that have been blown out by radiation pressure and stellar winds from the concealed stars. Silhouetted against the tenuous loops are clouds of dust with bright rims, which indicate the direction of the stars which power the nebula. This large complex of gas and dust is at about the same distance as the Eta Carinae Nebula, about 8,000 light years away. Copyright:(c) 1984 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[0158] Trifid Nebula in Sagittarius (Messier 20) Caption:Measuring some forty light years across, the Trifid nebula contains enough gas to make many thousands of stars. Within it a number of young hot stars have already formed. They cause the surrounding gas, mostly hydrogen, to emit its characteristic red light. However, one side of the nebula contains many dust grains that reflect the stars' light, producing a bluish color. In some parts of the nebula the dust grains are so numerous that they hide the glowing gas, producing three dark lanes, which give this beautiful object its name. Copyright:(c) 1977 Anglo-Australian Telescope Board, photograph by David Malin Credit:D. F. Malin

Title:[3071] A region of recent star formation in the Orion Nebula (HST) Caption:A close up view of part of the Orion Nebula taken with the Hubble Space Telescope on 29 December 1993. It is a region where star formation took place as recently as 300,000 years ago. The nebula is a giant gas cloud, 1,500 light years away, illuminated by the brightest of the young hot stars at the top of the picture. Many of the fainter young stars are surrounded by disks of dust and gas that are slightly more than twice the diameter of the solar system. Copyright: Credit:C. R. O'Dell and NASA