Mensa Constellation Map

صورة

الشرح: The constellation Mensa with its brighter stars and surrounding constellations. Mensa is surrounded by (going clockwise from the top): Dorado, Hydrus, Octans, Chamaeleon and Volans. Mensa is a faint constellation with relatively few bright stars. Mensa lies close to the south celestial pole and thus the whole constellation is visible at some point in the year throughout the southern hemisphere. The whole constellation is visible to a thin strip of the northern hemisphere around the equator with parts of the constellation visible to some other northern equatorial regions. Mensa is circumpolar in temperate, antarctic and some equatorial regions of the southern hemisphere. Mensa is best viewed in the evenings in the northern hemisphere winter and southern hemisphere summer. The Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way, lies in Mensa and the neighboring constellation Dorado. The outline of the Large Magellanic Cloud is marked here as a roughly circular loop in green. This diagram maps an area around the south celestial pole. Here lines of constant right ascension converge. The right ascension values of these lines are marked on the x-axis above and below the diagram. The solid circle around the pole marks a line of -80° declination with the larger, incomplete circle to the right marking -70° declination. 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.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope
رابط المصدر

مصطلحات المعجم: القدرالظاهري , الإحداثيات السماوية , مجموعة نجمية او حشد نجمى , الميل , المطلع المستقيم
فئات: علم الفلك بالعين المجردة

الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات

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Celestial Coordinates

صورة
أُنشئ لصالح OAE

الشرح: Here we see how celestial coordinates map positions on the celestial sphere. The celestial sphere is an imaginary, hollow sphere that surrounds the Earth. Celestial objects appear to be attached to the inside of the celestial sphere, and the planets, Sun, and Moon appear to move slowly across it. The celestial sphere has a spherical coordinate system similar to the latitude and longitude we see on the Earth. The celestial equator is the projection of the Earth's equator onto the celestial sphere while the north and south celestial poles are the projections of the Earth's north and south poles onto the celestial sphere. Declination is similar to latitude on the Earth in that it marks the angle above and below the celestial equator. Declination is zero on the celestial equator, is positive to the north of the celestial equator and negative to the south of it. It is commonly measured in degrees and sometimes in radians. Right Ascension is similar to longitude as it marks the angle around the celestial equator. As with longitude the zero point of right ascension (shown here as a dashed line) is a matter of choice. Traditionally the zero point of right ascension was the position of the Sun at the northern hemisphere vernal equinox (spring equinox) in March. It is positive and increases to the east, unlike longitude on Earth which is defined as east or west of the prime meridian. It is most commonly measured in hours, minutes and seconds or occasionally in degrees or radians. The ecliptic marks the Sun's path across the celestial sphere when viewed from the Earth. The Earth rotates within the celestial sphere. This leads to objects like stars or galaxies, which appear static on the celestial sphere, rising and setting when viewed from the Earth but remaining in the same position on the celestial sphere. The Earth's axis precesses within the celestial sphere. This slowly moves the celestial equator and the celestial poles meaning that the traditional celestial coordinate system changes slowly over time meaning that stars and galaxies that do not move will have positions that change. Astronomers have used coordinate systems defined by the position of the celestial poles and equator at a fixed point in time. Now celestial positions are most commonly measured on a fixed coordinate system defined by the position of the celestial poles and equator on the 1st of January 2000.
المصدر: Maria Cristina Fortuna/IAU OAE

فئات: علم الفلك بالعين المجردة , علم الفلك الرصدي

الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات

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Antlia Constellation Map

صورة

الشرح: The constellation Antlia along with its bright stars and surrounding constellations. Antlia is surrounded by (going clockwise from the top): Hydra, Pyxis, Vela and Centaurus. Antlia is a southern constellation that is visible at some point in the year from the whole southern hemisphere as well as equatorial and some temperate regions of the northern hemisphere. The constellation is best viewed in the evenings in the northern hemisphere spring and southern hemisphere autumn. 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.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope
رابط المصدر

مصطلحات المعجم: القدرالظاهري , الإحداثيات السماوية , مجموعة نجمية او حشد نجمى , الميل , المطلع المستقيم
فئات: علم الفلك بالعين المجردة

الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات

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Equuleus Constellation Map

صورة

الشرح: The constellation Equuleus with its brighter stars and surrounding constellations. Equuleus is surrounded by (going clockwise from the top): Delphinus, Aquarius and Pegasus. It is a relatively small constellation with few bright stars. Equuleus lies just north of the celestial equator and thus the whole constellation is visible at some point in the year to all but the most antarctic regions. Equuleus is best viewed in the evening in the early northern hemisphere autumn and early southern hemisphere spring. 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.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope
رابط المصدر

مصطلحات المعجم: القدرالظاهري , الإحداثيات السماوية , مجموعة نجمية او حشد نجمى , الميل , المطلع المستقيم , الدلو
فئات: علم الفلك بالعين المجردة

الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات

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Lynx Constellation Map

صورة

الشرح: Lynx is a northern constellation and thus the whole constellation is visible at some point in the year throughout the northern hemisphere. The whole constellation is also visible in equatorial regions of the southern hemisphere with parts of the constellation visible in southern temperate regions. Lynx is best viewed in the evenings in the northern hemisphere winter and southern hemisphere summer. 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. The blue line at the bottom right of the diagram marks the ecliptic. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
المصدر: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope
رابط المصدر

مصطلحات المعجم: القدرالظاهري , الإحداثيات السماوية , مجموعة نجمية او حشد نجمى , الميل , مسار البروج , الجوزاء , كوكبة الأسد , المطلع المستقيم , كوكبة السرطان
فئات: علم الفلك بالعين المجردة

الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات

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