Glossarbegriffe: Scheinbare Helligkeit
Description: Die scheinbare Helligkeit ist ein Maß dafür, wie hell ein Himmelskörper einem Beobachter erscheint. Sie wird als Magnitude (mag) angegeben, einer Zahl auf einer logarithmischen Skala, wobei ein Unterschied von 5 Magnituden einem Faktor von 100 in der gemessenen Helligkeit entspricht. Aus historischen Gründen haben weniger helle Objekte größere Zahlen auf der Magnitudenskala.
Es gibt viele Magnitudenskalen, da die Helligkeit bei verschiedenen Wellenlängen und mit verschiedenen Techniken gemessen werden kann. Die Skala der "visuellen Helligkeit" ist so eingestellt, dass der helle Stern Wega eine scheinbare Helligkeit von Null hat. Auf dieser Skala hat Sirius, der hellste Stern am Nachthimmel, eine Helligkeit von -1,46. Die Helligkeit der Sonne und des Vollmondes beträgt -26,7 bzw. -12,7. Die negativen Zahlen bedeuten, dass diese Objekte heller erscheinen als Wega. Unter sehr dunklen Bedingungen können Menschen mit ausgezeichnetem Sehvermögen Sterne mit einer visuellen Helligkeit von bis zu 6 mag sehen. Das Hubble Ultra Deep Field erreicht eine visuelle Helligkeit von etwa 31. Das ist etwa 100 hoch 5 oder 10.000.000.000 Mal weniger hell als die Magnitude 6.
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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher The translation of this term and its definition is still awaiting approval
The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".
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In Other Languages
- Arabisch: القدرالظاهري
- Englisch: Apparent Magnitude
- Spanisch: Magnitud Aparente
- Französisch: Magnitude apparente
- Italienisch: Magnitudine apparente
- Japanisch: 見かけの等級 (external link)
- Vereinfachtes Chinesisch: 视星等
- Traditionelles Chinesisch: 視星等
Related Diagrams
Andromeda Constellation Map
Bildunterschriften: The constellation Andromeda showing the bright stars and surrounding constellations. Andromeda is surrounded by (going clockwise from the top) Cassiopeia, Lacerta, Pegasus, Pisces, Aries, Triangulum and Perseus. The brightest star in Andromeda (Alpheratz) is in the lower part of the constellation. Together with three stars in Pegasus it forms the asterism known as the "Great Square of Pegasus". The next two bright stars in the constellation (Mirach and Almach) form a line extending north-east from Alpheratz.
Andromeda is a northern constellation and is most visible in the evenings in the Northern Hemisphere autumn. It is visible from all of the Northern Hemisphere and most temperate regions of the Southern Hemisphere but is not visible from Antarctic and Subantarctic regions.
The most famous object in Andromeda, the Andromeda Galaxy is marked here with a red ellipse and its Messier catalog number M31.
The yellow circle on the left marks the position of the open cluster NGC 752 and the green circle on the right marks NGC 7662 (the blue snowball nebula), a planetary nebula.
The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Bildnachweis: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope
License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons
Crux Constellation Map
Bildunterschriften: The constellation Crux (commonly known as the Southern Cross or Crux Australis) showing its bright stars and surrounding constellations. The Southern Cross is surrounding by (going clockwise from the top) Centaurus, Carina and Musca. The brightest star is alpha Crucis which appears at the bottom of the constellation's famous kite shape. The Southern Cross is visible from southern and equatorial regions of the world. In more southerly parts of the world it is circumpolar so is always above the horizon. In other parts of the southern hemisphere and in equatorial regions it is most visible in the evenings in the southern hemisphere autumn.
The yellow circles show the locations of two open clusters, NGC 4755 (known as the Jewel Box) and NGC 4609.
The line joining gamma and alpha Crucis (the third and first brightest stars in the Southern Cross) points in the approximate direction of the South Celestial Pole. This has led to the Southern Cross playing an important role in celestial navigation, allowing navigators from different astronomical traditions to find their bearings.
The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.
Bildnachweis: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope.
License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons
Orion-Sternkarte
Bildunterschriften: Das Sternbild Orion mit seinen hellen Sternen und den umliegenden Sternbildern. Im Uhrzeigersinn von Oben ist Orion umgeben von dem Stier, Eridanus, dem Hasen, dem Einhorn und Zwilling. Die hellsten Sterne des Orion, Betelgeuze und Rigel, befinden sich am nördlichen (in dieser Abbildung oberen) bzw. südlichen (unteren) Ende des Sternbilds, mit dem berühmten Dreisternegürtel in der Mitte.
Orion erstreckt sich über den Himmelsäquator und ist daher im Laufe des Jahres irgendwann von der gesamten Erde aus sichtbar. In den arktischen oder antarktischen Regionen der Welt sind einige Teile des Sternbilds möglicherweise nicht sichtbar. Orion ist am besten Abends im Winter auf der Nordhalbkugel und im Sommer auf der Südhalbkugel zu sehen. Die blaue Linie über Orion markiert die Ekliptik, also den Weg, den die Sonne im Laufe eines Jahres über den Himmel zu gehen scheint. Die Sonne läuft nie durch den Orion, aber man kann gelegentlich die anderen Planeten des Sonnensystems und den Mond im Orion finden.
Direkt südlich des Gürtels des Orion liegen die beiden Messier-Objekte M42 (der Orionnebel) und M43, die durch grüne Quadrate gekennzeichnet sind. Diese Nebel sind zusammen mit M78 (hier das grüne Quadrat links vom Gürtel) Teil des riesigen Orion-Molekülwolkenkomplexes. Dieser erstreckt sich über den größten Teil des Sternbilds und umfasst Regionen, in denen diese Molekülwolken kollabieren und junge Sterne bilden.
Die y-Achse dieses Diagramms ist in Deklinationsgraden mit Norden nach oben und die x-Achse in Rektaszensionsstunden mit Osten nach links angegeben. Die Größe der hier markierten Sterne bezieht sich auf die scheinbare Helligkeit des Sterns. Je größer die Punkte, desto heller scheinen die Sterne die sie darstellen. Die griechischen Buchstaben kennzeichnen die hellsten Sterne des Sternbildes. Sie sind nach Helligkeit geordnet, wobei der hellste Stern mit Alpha, der zweithellste mit Beta usw. bezeichnet wird, obwohl diese Reihenfolge nicht immer genau eingehalten wird. Der Kreis um Betelgeuse zeigt an, dass es sich um einen veränderlichen Stern handelt. Die gepunkteten Begrenzungslinien markieren die IAU-Grenzen der Sternbilder und die durchgezogenen grünen Linien markieren eine der üblichen Formen, die zur Darstellung der Sternbilder verwendet werden. Weder die Sternbildgrenzen noch die Linie, die die Ekliptik markiert, noch die Linien, die die Sterne miteinander verbinden, sind so am Himmel sichtbar.
Bildnachweis: Angepasst vom IAU Office of Astronomy for Education nach dem Original von IAU/Sky & Telescope
License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons
Libra Constellation Map
Bildunterschriften: The constellation Libra along with its bright stars and surrounding constellations. Libra is surrounded by (going clockwise from the top) Serpens Caput, Virgo, Hydra, Centaurus, Lupus, Scorpius and Ophiuchus. Libra lies on the ecliptic (shown here as a blue line), this is the path the Sun appears to take across the sky over the course of a year. The Sun is in Libra from late October to late November. The other planets of the Solar System can often be found in Libra.
Libra lies just south of the celestial equator and is thus visible at some time in all but the most arctic regions. Libra is most visible in the evenings in the northern hemisphere late spring/early summer and southern hemisphere late autumn/early winter.
The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
Bildnachweis: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope
License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons
Scorpius Constellation Map
Bildunterschriften: The constellation Scorpius (often commonly called Scorpio) along with its bright stars and surrounding constellations. Scorpius is surrounded by (going clockwise from the top) Ophiuchus, Serpens Caput, Libra, Lupus, Norma, Ara, Corona Australis and Sagittarius. Scorpius’s brightest star Antares appears in the heart of the constellation with the famous tail of Scoprius in the south-east (lower left). Scorpius lies on the ecliptic (shown here as a blue line), this is the path the Sun appears to take across the sky over the course of a year. The Sun only spends a short amount of time in late November in Scorpius. The other planets of the Solar System can often be found in Scorpius.
Scorpius lies south of the celestial equator. The whole constellation is not visible from the most arctic regions of the world with parts of Scorpius obscured for observers in northern parts of Asia, Europe and North America. Scorpius is most visible in the evenings in the northern hemisphere summer and southern hemisphere winter.
The yellow circles mark the positions of the open clusters M6, M7 & NGC 6231 while the yellow circles with plus signs superimposed on them mark the globular clusters M4 and M80.
The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The circle around Antares indicates that it is a variable star. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. The blue line marks the ecliptic, the path the Sun appears to travel across the sky over the course of one year. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
Bildnachweis: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope
License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons
