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| ASTRONOMICAL IMAGES |
In this gallery you will find astronomical images taken at the telescope site. In the parallell gallery, there are images of the telescope and the site.
Please read the copyright text below.
You can go directly to the images in the gallery, which are placed in the main structure Galaxies, the Milky Way and the solar system. As an alternative you can use the quick links to jump to one of the sixteen main group of images. These links are place in order of general size of the objects or distances to them. Attached to these links are a short description of the type of object.
Within each group the images are place in alphabetical order according to the label used.
| Meteor | Images of objects burning when entering our atmosphere. Meteors (often refered to as falling stars) enters the atmosphere at high speed (generally a few tenths of km/s). The pre meteor object, the meteoroid (if of natural origin) is in dust to small rock size. The meteor lights up at an altitude of about 100 km. The atmosphere up there is to thin for sound to travel properly so any sound heard must come from radio signal produced. A metoeor usually last for about a second, but larger meteroids produce bolids, longer lasting bright meteors, which can even be seen during day time and leave a smoke tail. These bolids often defragentates and sometime explode in the air. Pieces of a meteor which survive the atmosphere can be picked up as meteorite. Sometimes meteors come in a shower originating from a radiant in the sky. These objects enters the atmosphere on a parallell course (compare how a road going into the distance looks like) and are the debrees of a comet left along it's orbit, which the Earth is crossing during the shower. Showers are yearly events but the intesity can change a lot from year to year. |
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| Spaceprobe | Images of man made objects. | |
| Comet | Images of comets. Comets are objects with a large portion or mainly consisting of different types of ice, mostly that of water. When the comet is close to the Sun (about the distance of the asteroid belt) the abundant water ice can sublimate (go directly from solid to gas) at a high rate. This water gas is draging along dust particles which make up the coma and tail, which points away from the sun. The actual comet is usually some 1-10 km in size while the coma is of the order 100000 km. If the orbit of the comet crosses that of the Earth, these particles might produce a meteor shower. The two main reservoars for comets are the Oort cloud surrounding the solar system about a light year away (or some tens of thousand of the Earth-Sun distance) and the Kuiperbelt, beyond the orbit of Neptune. |
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| Asteroid | Images of objects with orbits from Jupiter and towards the Sun. Asteroids are generally bodies of rock materials with sizes ranging from a few tens om meter up to almost 1000 km. Most asteroids can be found in the main asteroid belt between Mars and Jupiter (about 2-3 Sun-Earth distances) but about 1% have orbits taking them to the vicinity of the Earth (Near Earth Asteroids) and some are trapt in regions governed by Jupiter like the Hilda and Trojan groups. Several hundred thousands orbit of Asteroids are known and kept track of by the Minor Planet Center. |
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| Moon | Images of moons. A moon (or satellite) is a body primarely orbiting a planet (or other object larger than it self (several asteroids are known to have moons)). The sizes ranges up to more than 5000 km (larger than planet Mercury). Some moons were formed together with their larger companion while others have been captured. Earth's moon is belived to be the reaccumulation from a collision with a planet size body early in the solar system history. |
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| Outer solar system | Images of objects beyond the orbit of Jupiter, but not comets or planets. Objects with orbits beyond the orbit of Jupiter have probably a large portion of ice in them. If they came closer to the Sun many would become comets. Most of the known objects today can be found in the Kuiperbelt beyond the orbit of Neptune, but several groups have orbits crossing one or more planet orbits. Many of these objects are large enough to be spherical (i.e. roughly 1000 km size). Pluto is the largest member of the Plutino group, objects in a similar type of orbit as the Hilda group. Pluto's moon Charon is so large compared to Pluto that the two sometimes refers to a binary system rather than a main body and a moon. |
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| Planet | Images of planets. Planets are large (more or less spherical) bodies primarely orbiting a star but not capable of fuse material in the interior. In the solar system today there are eight major (or classical) planets and a growing group of dwarf planets to which both the Kuiperbelt object Pluto and the asteroid Ceres can be counted. Several hundred exoplanets (planets around stars other than the Sun) are known. |
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| Sun | Images of the Sun. In our solar system the Sun is the star, that is a body that produces it's own internal energy by fusion. Our Sun is roughly 750 times more massive than all other bodies in the solar system combined. It is classified as a main sequence G-type dwarf star and it is roughly middle aged. Although the Sun's apparent size is about the same as the moon, the Sun is more than 400000 times brighter than the full moon. |
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| Star | General images containing stars. A star is an object that can produce it's onw energy by fusion. This limit is 80 Jupiter masses. A transitional type of object are the brown dwarfs, which briefly can fuse deuterium. Stars are often compared to so called black bodies (objects which emits light as a Planc spectrum). The color of the star depends on the temperature in the stellar atmosphere. A bluish star is hotter than a white star, which is hotter than a yellow star followed by orange and red. It is common to have stars in binary or multiple systems. |
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| Open cluster | Images of open stellar clusters. Open clusters are groups of usually relatively young stars with similar chemical composition. The reason for this is that stars are often born in large gas clouds capable of producing hundreds or thousands of stars. The process is self triggering i.e. stellar births will trigger more stellar births so the age is fairly homogeneous. Many of these open clusters are not gravitationally bound groups i.e. they will dissipate with time, joining the stellar field population. |
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| Nebula | Images of gas clouds, nebulas. Nebula means cloud or mist and until the 1920s gathered all dim objects in the night sky, except for comets. Nowadays nebula is refering to gas and dust clouds. There are several types of nebulas. Reflection nebula and emission nebulas are in principle the same thing but with different viewing geometries. Reflection nebulas are blue by the scattered light from a near by star placed between us and the cloud. If the cloud is between us and the star the penetrating red light is seen if the cloud is not too thick and we have an emission nebula. A thicker cloud which block all light from beyond is called a dark nebula and can be seen due to the difference in stellar density when the light from the far of stars are blocked. Two other types of nebula are the remnants from stellar deaths. A planetary nebula is the remnant, ejected outer parts from a star of about the mass of the Sun and are illuminated by the white dwarf, the hot core of the former star. These nebulas are often more or less spherical in appearance. The other stellar death type give rise to supernova remnants, the left over from a stellar explosion. They are illuminated from the remaining neutron star or when the stellar gas collides with denser interstellar matter or gas clouds. |
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| Globular cluster | Images of old stellar concentrations. Globular clusters are concentrations of hundreds of thousand (or more) of stars. These clusters are graviationally bound and generally old. They are acting as satellites around galaxies. They can also occationally move through galaxies without much trouble due to the vast space between stars. |
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| Constellation | Images of constellations. Constellations are not true astronomical objects but the apparent brightness of stars which are generally not close to each other in radial direction. In some cases the brightest stars in a region forms a pattern that might resemble something and thus giving rise to a name for that group of stars. The reference to a star in a particular constellation has for a long time served a logistic purpose of pinpointing where on the sky a star is located. Today the sky is divided into a number of constellations with boundaries. Most names comes from greek (roman) mythology, but many of them goes back on older traditions, some predates history. With computerized telescopes there is no need of a constellation reference in order to locate a star. The constellations shown here are those accessible from this site, and the drawings are in most cases the same as used on the IAU site. |
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| Irregular galaxy | Images of irregular galaxies. Irregular galaxies are generally smaller galaxies which can be gas rich, underdeveloped or been subjects for galaxy collisions. The Magellanic clouds, companions to the Milky Way in the southern sky are two examples. |
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| Spiral galaxy | Images of spiral galaxies. Spiral galaxies are disc shaped objects with arm and possibly bar structure. A typical spiral galaxy can be about 100000 light years across and contain some 100000000000 stars. Our Milky Way is a spiral galaxy with a central bar. The central area usually contains a mix of young and old stars. The disc contains mostly younger stars and much of the gas and dust can be found in the spiral arms. |
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| Elliptical galaxy | Images of elliptical galaxies. The elliptical galaxies lacks spiral structure. There are almost no gas and dust in these galaxies and hence very few young stars. The elliptical galaxies can be both larger and smaller than spiral galaxies. Small elliptical galaxies may contain only a few million stars. The stellar motion is more random than in the spiral galaxies, generally the more spherical the shape the more isotropic motion. |
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