Caption: 獵戶座及其明亮的恆星和周圍的星座。獵戶座被金牛座、波江座、天兔座、麒麟座和雙子座環繞（從上往下順時針依次排列）。獵戶座最亮的恆星參宿四和參宿七分別位於星座的北端（圖中上部）和南端（圖中下部），中間是著名的三星 "腰帶"。 獵戶座橫跨天赤道，因此在一年中的某些時候，從地球上的任何地方都能看到它。在世界上最北極或最南極地區，可能看不到獵戶座的某些部分。獵戶座在北半球冬季和南半球夏季的晚上最為明顯。獵戶座上方的藍線標誌著黃道，即太陽在一年中劃過天空的軌跡。太陽從不經過獵戶座，但人們偶爾會在獵戶座發現太陽系的其他行星和月球。 在獵戶座腰帶的正南方，有兩個梅西葉天體M42（獵戶座星雲）和M43，用綠色方框標出。這些星雲和M78（腰帶左邊的綠色方框）是巨大的獵戶座分子雲團的一部分。它覆蓋了獵戶座的大部分區域，包括這些分子雲正在坍縮形成新星的區域。 該圖的 y 軸表示赤緯，單位為度數，以北為上，x 軸表示赤經，單位為小時，以東為左。這裡標注的恆星大小與恆星的視星等有關，視星等是衡量恆星視亮度的標準。較大的點代表較亮的恆星。希臘字母表示星座中的亮星。這些恆星按亮度排序，最亮的恆星被標記為α星，第二亮的為β星，等等，不過並不總是完全遵循這種排序。圍繞著參宿四的圓圈表示它是一顆變星。虛線是國際天文學聯合會劃定的星座邊界，綠色實線是表示星座的常用形式之一。星座邊界和連接恆星的線條都不會出現在實際天空中。
Credit: 由國際天文學聯合會天文教育辦公室根據國際天文學聯合會/《天空與望遠鏡》的原文改編

Caption: 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The constellation Sagittarius along with its bright stars and surrounding constellations. Sagittarius is surrounded by (going clockwise from the top) Aquila, Scutum, Serpens Cauda, Ophiuchus, Scorpius, Corona Australis, Telescopium, Microscopium and Capricornus. The brighter stars in Sagittarius form a distinctive teapot shape. Sagittarius 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 Sagittarius from mid December to mid January. The other planets of the Solar System can often be found in Sagittarius. Sagittarius lies south of the celestial equator. The famous teapot asterism is visible for all but the most arctic regions of the world but the most southerly parts of the constellation are not visible in northern parts of Asia, Europe and North America. Sagittarius is most visible in the evenings in the northern hemisphere summer and southern hemisphere winter. The supermassive black hole Sagittarius A* which lies at the center of our Milky Way Galaxy is sits on the western (here right-hand) edge of Sagittarius. Due to it covering an area at the center of our Galaxy, Sagittarius is home to many star clusters including open clusters (marked here with yellow circles) and globular clusters (marked here with yellow circles with + signs superimposed on them). Three nebulae are also marked here with green squares. 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The constellation Capricornus (commonly called Capricorn) including its bright stars and surrounding constellations. Capricornus is surrounded by (going clockwise from the top) Aquarius, Aquila, Sagittarius, Microscopium and Piscis Austrinus. Capricornus 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 Capricornus from mid January to mid February. The other planets of the Solar System can often be found in Capricornus. Capricornus lies just south of the celestial equator and is visible to all observers south of the Arctic Circle. Capricornus is most visible in the evenings in the northern hemisphere autumn and southern hemisphere spring. In the south east (lower left on this diagram) of the constellation one can find the globular cluster M30 (shown here as a yellow circle with a plus sign superimposed on it). 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: 寶瓶座及其明亮恆星與周邊星座示意圖。從頂部開始沿順時針方向，寶瓶座周邊的星座依次為：飛馬座、小馬座、天鷹座、摩羯座、南魚座、玉夫座、鯨魚座和雙魚座。寶瓶座位於黃道上。從地球看來，太陽以一年為週期在天球上移動，所經過的路徑稱為黃道，在圖中以藍色實線標注。太陽在每年二月中旬到三月中旬位於寶瓶座。太陽系中的其他行星也經常出現在寶瓶座。 寶瓶座橫跨天赤道，因此在地球上的任何地方，一年中的某些時候都能看到它。在地球南北兩極，寶瓶座的某些部分可能不可見。寶瓶座在北半球的秋季和南半球的春季夜晚最適宜觀測。 球狀星團M2和M72在圖中以疊加了十字符號的黃色圓圈標注。行星狀星雲NGC 7293（螺旋星雲）和NGC 7002（土星狀星雲）在圖中以疊加了十字符號的綠色圓圈標注。M73在圖中以叉號標注，它是一個偶然形成的恆星群，之前被錯誤歸類為疏散星團。 該圖的縱軸為赤緯，橫軸為赤經，方向為上北下南左東右西。圖中標注的恆星大小對應其視星等——衡量天體視亮度的標準，較大的圓點代表著較亮的恆星。圖中的希臘字母標注著星座中最亮的恆星。這些恆星按亮度排序，最亮的一般被標記為α星，第二亮的一般為β星，等等，不過這種字母排序並不總是和實際亮度排序完全一致。圖中虛線標注的是國際天文學聯合會劃定的星座邊界，綠色實線則是一種常見的星座形象連線。需要注意的是，在實際觀測時，這些邊界與連線都不會出現在天空中。
Credit: 由國際天文學聯合會天文教育辦公室根據國際天文學聯合會/《天空與望遠鏡》的原文改編

Caption: 雙魚座及其明亮恆星與周邊星座示意圖。從頂部開始沿順時針方向，雙魚座周邊的星座依次為：仙女座、飛馬座、寶瓶座、鯨魚座、白羊座和三角座。雙魚座位於黃道上。從地球看來，太陽以一年為週期在天球上移動，所經過的路徑稱為黃道，在圖中以藍色實線標注。太陽在每年三月中旬到四月中旬位於雙魚座。因此，春分時太陽位於雙魚座——黃道在這裡與天赤道相交，而太陽在春分時的位置即為赤道坐標系中赤經坐標的原點。太陽系中的其他行星也經常出現在雙魚座。 雙魚座橫跨天赤道，因此在地球上的任何地方，一年中的某些時候都能看到它。在地球南北兩極，雙魚座的某些部分可能不可見。雙魚座在北半球的秋季和南半球的春季夜晚最適宜觀測。 宏偉的螺旋星系M74在圖中以紅色小圓圈標注。 該圖的縱軸為赤緯，橫軸為赤經，方向為上北下南左東右西。圖中標注的恆星大小對應其視星等——衡量天體視亮度的標準，較大的圓點代表著較亮的恆星。圖中的希臘字母標注著星座中最亮的恆星。這些恆星按亮度排序，最亮的一般被標記為α星，第二亮的一般為β星，等等，不過這種字母排序並不總是和實際亮度排序完全一致。圖中虛線標注的是國際天文學聯合會劃定的星座邊界，綠色實線則是一種常見的星座形象連線。需要注意的是，在實際觀測時，這些邊界與連線都不會出現在天空中。
Credit: 國際天文學聯合會天文教育辦公室（IAU OAE）根據國際天文學聯合會和《天空與望遠鏡》的原文改編

Caption: The constellation Aries along with its bright stars and surrounding constellations. Aries is surrounded by (going clockwise from the top) Triangulum, Pisces, Cetus, Taurus and Perseus. Aries 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 Aries from mid April to mid May. The other planets of the Solar System can often be found in Aries. Aries lies just north of the celestial equator and is thus visible at some time in the year from all of planet Earth except for the most antarctic regions of the world. Aries is most visible 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. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The constellation Taurus along with its bright stars and surrounding constellations. Taurus is surrounded by (going clockwise from the top) Perseus, Aries, Cetus, Eridanus, Orion, Gemini and Auriga. Taurus’s brightest star Aldebaran appears in the middle of the constellation. Taurus 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 Taurus from mid May to late June. The other planets of the Solar System can often be found in Taurus. Taurus lies mostly north of the celestial equator with a small part in the celestial southern hemisphere. The whole constellation is visible at some point in the year to whole planet except for the Antarctic and a small region around the North Pole. Taurus is most visible in the evenings in the northern hemisphere winter and southern hemisphere summer. In the eastern part of Taurus we can find the supernova remnant M1 (commonly known as the Crab Nebula), marked here with a green square. In Taurus’s north-east find one of the sky’s most famous open stars clusters M45 (the Pleiades), marked here with a yellow circle. Many of the stars near Aldebaran (but not) Aldebaran are members of another star cluster, the Hyades. However this cluster is close to the solar system so is too dispersed on the sky to have a Messier object designation like the Pleiades has. 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The zodiac constellation Cancer and its surrounding constellations. Starting from the top of the diagram and going clockwise, these are Lynx, Gemini, Canis Minor, Hydra, Leo and Leo Minor. The ecliptic (shown here as a blue line) passes almost exactly through the middle of the constellation, this is the path the Sun appears to take across the sky over the course of a year. The Sun is in Cancer from late July to mid August. The other planets of the Solar System can often be found in Cancer. Cancer lies just north of the celestial equator and is thus visible at some time in the year from all of planet Earth except for the most antarctic regions of the world. Cancer is most visible in the evenings in the northern hemisphere spring and southern hemisphere autumn. Two star clusters are visible in Cancer: M44, an open cluster often called the Beehive Cluster, and M46, a denser open cluster with about four times more stars than M44. These clusters are indicated by yellow circles with a dotted border on the map. 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 labelled 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The zodiac constellation Leo and its surrounding constellations. Starting from the top of the diagram and going clockwise, these are Leo Minor, Cancer, Sextans, Hydra, Crater, Virgo and Ursa Major. The brightest star in Leo, Regulus, lies almost exactly on the ecliptic (shown here as a blue line): the path the Sun appears to take across the sky over the course of a year. The Sun spends the period from mid August to mid September in Leo. The other planets in the Solar System can often be found in Leo. Leo spans the celestial equator and is thus part of it is visible at some time in the year from all of planet Earth with some of the constellation obscured for the most arctic and antarctic regions of the world. Leo is most visible in the evenings in the northern hemisphere spring and southern hemisphere autumn. Several objects can be seen in Leo, including M65 and M66 – two galaxies in the Leo Triplet, a trio of galaxies including NGC 3628, not listed here. In addition, M96, a spiral galaxy, can be seen as a fuzzy object using a small telescope, and Messier 105, an elliptical galaxy. Each of these objects are labelled on the map as red ellipses. 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 labelled 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The zodiac constellation Virgo and its surrounding constellations. Starting from the top of the diagram and going clockwise, these are Coma Berenices, Leo, Crater, Corvus, Libra, and Bootes. The brightest star in Virgo, Spica, lies just below the ecliptic (shown here as a blue line) in the middle of the map. One way of locating this star in the night sky is to follow the handle of the Big Dipper to the star Arcturus in Bootes and go along a line straight down to Spica (“arc to Arcturus and spike to Spica”). This star lies just below the ecliptic. The ecliptic is the path the Sun appears to take across the sky over the course of a year. The Sun is in Virgo from mid September to late October. The other planets of the Solar System can often be found in Virgo. Virgo spans the celestial equator and is thus part of it is visible at some time in the year from all of planet Earth with some of the constellation obscured for the most arctic and antarctic regions of the world. Virgo is most visible in the evenings in the northern hemisphere spring and southern hemisphere autumn. The constellation Virgo appears as a person lying with their back roughly against the ecliptic, arms outstretched, and feet pointed east. Several deep-sky objects are visible in Virgo, including NGC4697, M49, M87, M86, M84, and M60, all of which are labelled as red ellipses on the map. These are all spiral and elliptical galaxies located several millions of lightyears from Earth. Most notably, M87 is host to the supermassive black hole (Pōwehi) that was imaged by the Event Horizon Telescope in 2019. All of these galaxies are members of the Virgo Cluster, the nearest cluster of galaxies to the Milky Way. 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 labelled 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The constellation Ophiuchus along with its bright stars and its surrounding constellations. Ophiuchus is surrounded by (going clockwise from the top): Hercules, Serpens Caput, Scorpius, Sagittarius and Serpens Cauda. Ophiuchus is not part of the traditional twelve zodiac constellations but it 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 Ophiuchus from late November to mid December. The other planets of the Solar System can often be found in Ophiuchus. Ophiuchus spans the celestial equator and thus part of the constellation is visible across the whole of the earth at some point in the year. However during the time it is most visible in the evenings (the southern hemisphere winter and northern hemisphere summer) much of the arctic is in perpetual daylight making the stars in the constellation impossible to see. The whole constellation is visible from equatorial and temperate regions of both hemispheres. As Ophiuchus lies close to the galactic center it contains many globular clusters such as M9, M10, M12, M14, M19, M62, and M107. These are marked as yellow circles with plus symbols superimposed. 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The zodiac constellation Gemini and its surrounding constellations. Starting from the top of the diagram and going clockwise, these are Auriga, Taurus, Lynx, Orion, Monoceros, Canis Minor and Cancer. The brightest stars in Gemini, Castor and Pollux appear in the upper lefthand corner (north-east) of the diagram. In Greek mythology, the stars in this constellation are thought to resemble twins with their arms wrapped around each other, with Castor and Pollux indicating their heads. Gemini 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 Gemini from late June to late July. The other planets of the Solar System can often be found in Gemini. Gemini lies north of the celestial equator and is visible in all but the antarctic regions of the world. Gemini is most visible in the evenings in the northern hemisphere winter and southern hemisphere summer. Just to the right of the foot of the Castor twin is an open cluster of stars (labelled as a yellow circle with a dotted line border), Messier 35, also known as the Shoe-Buckle Cluster. This cluster is spread out over an area roughly the size of the full moon. In addition to this cluster of stars, there is a planetary nebula (labelled as a green circle with four radial spikes) – NGC 2392 – near the celestial equator and just to the left of the Pollux twin. Two variable stars (Mekbuda and Propus; labelled as two concentric circles) can be found in the “legs” of each twin, but are so faint that an observer would need dark skies to see them. 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 labelled 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The constellation Cetus along with its bright stars and surrounding constellations. Cetus is surrounded by (going clockwise from the top): Pisces, Aquarius, Sculptor, Fornax, Eridanus, Taurus and Aries. Cetus lies just south of 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. While the Sun does not pass through Cetus, the other planets of the solar system and the Moon can sometimes be found in Cetus. The star Omicron Ceti or Mira is a famous variable star. This red giant varies in brightness by a factor of 600 over the course of its eleven month period. Cetus spans the celestial equator, thus some part of the constellation is visible from all the the Earth at some point in the year. The full constellation is visible from equatorial and temperate regions of both hemispheres. Cetus is most visible in the evenings in the northern hemisphere late autumn and the southern hemisphere late spring. The barred spiral galaxy M77 lies in Cetus as does the spiral galaxy NGC 247 and the dwarf irregular galaxy IC 1613. All three are marked here with red ellipses. 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. Mira is marked with an open circle as it is a variable star not always visible to the naked eye. 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The constellation Auriga with its bright stars and surrounding constellations. Auriga is surrounded by (going clockwise from the top): Camelopardalis, Perseus, Taurus, Gemini and Lynx. Capella, the brightest star in Auriga, is the sixth brightest star in the night sky. As a northern constellation, Auriga is visible from the whole of the northern hemisphere at some point in the year. The whole of the constellation is visible to equatorial regions of the southern hemisphere with parts of it visible to temperate southern regions. The whole constellation is circumpolar from arctic regions. The constellation is best viewed in the evening in the late northern hemisphere winter and late southern hemisphere summer. Auriga lies in the plane of the Milky Way and thus hosts a number of open clusters. Of these M36, M37 and M38 are marked on this diagram with yellow circles. IC 405, also known as the flaming star nebula, is marked here with a green square. 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 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Aquila with its bright stars and surrounding constellations. Aquila is surrounded by (going clockwise from the top): Sagitta, Hercules, Ophiuchus, Serpens Cauda, Scutum, Sagittarius, Capricornus, Aquarius and Delphinus. Aquila is most notable for its brightest star Altair. This forms one vertex of the prominent Summer Triangle asterism that is visible in northern hemisphere summer evenings. Aquila spans the celestial equator and thus some part of it is visible from all of the Earth at some point in the year. It is most visible in the evenings in the late northern hemisphere summer and late southern hemisphere 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. The blue line in the lower right of the diagram is the ecliptic. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by IAU/Sky & Telescope

Caption: The constellation Canis Minor with its bright stars and surrounding constellations. Canis Minor is surrounded by (going clockwise from the top): Gemini, Monoceros, Hydra and Cancer. Canis Minor has relatively few bright stars but its brightest star Procyon is the eight brightest star in the sky. Canis Minor spans the celestial equator and thus part of the constellation is visible from the whole Earth at some point during the year. The whole constellation is visible to all but the most arctic and antarctic regions. 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 in the top 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Corona Australis with its brighter stars and surrounding constellations. Corona Australis is surrounded by (going clockwise from the top): Sagittarius, Scorpius, Ara and Telescopium. This constellation has relatively few bright stars. Corona Australis is a southern constellation and thus the whole constellation is visible in the southern hemisphere at some point in the year. The constellation can also be viewed from equatorial and some temperate regions of the northern hemisphere. The constellation is best viewed in the evening in the northern hemisphere summer and southern hemisphere winter. The globular cluster NGC 6541 lies in Corona Australis and is marked here with a yellow circle with a plus sign superimposed on it. 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. The blue line at the top right of the diagram marks the ecliptic.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Coma Berenices with its brighter stars and surrounding constellations. Coma Berenices is surrounded by (going clockwise from the top): Canes Venatici, Ursa Major, Leo, Virgo and Boötes. This constellation has relatively few bright stars. Coma Berenices is a northern constellation close to the celestial equator. As such the whole constellation is visible at some point in the year everywhere on Earth except the most antarctic regions. The constellation is best viewed in the evening in the northern hemisphere late spring and southern hemisphere late autumn. Coma Berenices is home to a large cluster of galaxies known as the Coma Supercluster. However none of the galaxies in this cluster are marked on this diagram as they are too faint to observe with most amateur telescopes. The elliptical galaxy M85 and the spiral galaxy M100 are members of the nearer Virgo cluster of galaxies. These are marked with red ellipses as are the even nearer M64 and NGC 4565, both of which are spiral galaxies. The globular cluster M53, marked here with a yellow circle with a plus sign superimposed on it, also lies in Coma Berenices. 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Hydra with its bright stars and surrounding constellations. Hydra is surrounded by (going clockwise from the top): Leo, Cancer, Canis Minor, Monoceros, Puppis, Pyxis, Antlia, Centaurus, Lupus, Libra, Virgo, Corvus, Crater and Sextans. Hydra is a large constellation that covers over a quarter of the celestial sphere in right ascension. It also spans the celestial equator and thus part of the constellation is visible from everywhere on the Earth at some point in the year. All parts of the constellation are visible at some point for all but the most antarctic parts of the southern hemisphere and to equatorial and most temperate regions of the northern hemisphere. However the wide span of the constellation means that all of it may not be visible at the same time in many of these regions. Hydra is best viewed in the northern hemisphere spring and southern hemisphere autumn. The famous spiral galaxy M83, also known as the Pinwheel Galaxy, lies in Hydra. It is marked here with a red ellipse. The planetary nebula NGC 3242 can also be found in Hydra. It is marked here with a green circle with a plus sign superimposed on it. The open cluster M48 is marked here with a yellow circle while the globular cluster M68 is marked with a yellow circle with a plus sign superimposed on it. 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 on 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Leo Minor with its brighter stars and surrounding constellations. Leo Minor is surrounded by (going clockwise from the top): Ursa Major, Lynx, Cancer and Leo. Leo Minor is a small constellation with relatively few bright stars. It is a separate constellation from and should not be confused with its larger neighbour Leo. Leo Minor 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 from equatorial and temperate regions of the southern hemisphere. Leo Minor is circumpolar in arctic regions. This constellation is best viewed 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. The blue line in the bottom right marks the ecliptic.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Lupus with its bright stars and surrounding constellations. Lupus is surrounded by (going clockwise from the top): Libra, Hydra, Centaurus, Circinus, Norma and Scorpius. Lupus is a southern constellation and thus the whole constellation is visible at some point in the year throughout the southern hemisphere. The whole constellation is visible in equatorial and some temperate regions of the northern hemisphere with parts of the constellation visible to remaining temperate regions. Lupus is best viewed in the evenings in the northern hemisphere summer and southern hemisphere 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. The blue line in the top left 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: 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.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Microscopium with its brighter stars and surrounding constellations. Microscopium is surrounded by (going clockwise from the top): Capricornus, Sagittarius, Telescopium, Indus, Grus and Piscis Austrinus. Microscopium is a faint constellation with relatively few bright stars. Microscopium is a southern constellation and thus the whole constellation is visible at some point in the year throughout the southern hemisphere. The whole constellation is also visible in equatorial and some temperate regions of the northern hemisphere with parts of the constellation visible from other northern temperate regions. Microscopium is best viewed in the evening in the northern hemisphere autumn and 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 line marking the ecliptic, nor the lines joining the stars appear on the sky. The ecliptic is marked with a blue line in the top right.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Pegasus with its bright stars and surrounding constellations. Pegasus is surrounded by (going clockwise from the top): Lacerta, Cygnus, Vulpecula, Delphinus, Equuleus, Aquarius, Pisces and Andromeda. Pegasus is known for the prominent asterism the “Square of Pegasus” which consists of its three brightest stars plus the brightest star in Andromeda. Pegasus 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 to southern hemisphere equatorial and temperate zones with parts of the constellation visible from all but the most antarctic regions. Pegasus is best viewed in the evening in the northern hemisphere autumn and southern hemisphere spring. The globular cluster M15 lies in Pegasus and is marked here with a yellow circle with a plus sign superimposed on it. The spiral galaxy NGC 7331 also lies in Pegasus and is marked here with a red ellipse. 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 of the diagram marks the ecliptic. Neither the constellation boundaries, nor the lines joining the stars, nor the ecliptic, appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Perseus with its bright stars and surrounding constellations. Perseus is surrounded by (going clockwise from the top): Camelopardalis, Cassiopeia, Andromeda, Triangulum, Aries, Taurus and Auriga. Perseus is home to the notable variable star Algol. Perseus 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 to equatorial regions of the southern hemisphere with parts of the constellation visible to southern temperate regions. Perseus is best viewed in the evenings in the northern hemisphere winter and southern hemisphere summer. The open clusters NGC 869 and NGC 884 (commonly known as the Double Cluster) lie in Perseus as does the open cluster M34. These are all marked with yellow circles. The brightest star in Perseus, Mirfak (alpha Persei), along with some of the surrounding stars are members of the Alpha Persei open cluster. The planetary nebula M76 also lies in Perseus, it is marked here with a green circle superimposed on a plus sign. 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 dot marking Algol is surrounded by a circle, showing 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 at the bottom left of the diagram marks the ecliptic. Neither the constellation boundaries, nor the lines joining the stars, nor the ecliptic, appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Sextans with its brighter stars and surrounding constellations. Sextans is surrounded by (going clockwise from the top): Leo, Hydra and Crater. Sextans is a small constellation with relatively few bright stars. Sextans spans the celestial equator and thus parts of the constellation are visible at some point in the year across the Earth. The whole constellation is visible in all but the most arctic and most antarctic regions. Sextans is best viewed in the evening in the northern hemisphere spring and southern hemisphere autumn. The lenticular galaxy NGC 3115 lies in Sextans. It is marked here with a red ellipse. 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 top of the diagram marks the ecliptic. Neither the constellation boundaries, nor the lines joining the stars, nor the ecliptic, appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Piscis Austrinus with its bright stars and surrounding constellations. Piscis Austrinus is surrounded by (going clockwise from the top): Aquarius, Capricornus, Microscopium, Grus and Sculptor. Piscis Austrinus is a southern constellation and thus the whole constellation is visible at some point in the year throughout the southern hemisphere. The whole constellation is also visible to some equatorial regions of the northern hemisphere with parts of the constellation visible to the remaining equatorial and some temperate northern hemisphere regions. Piscis Austrinus is best viewed in the evening in the northern hemisphere autumn and 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. The blue line in the top right of the diagram marks the ecliptic. Neither the constellation boundaries, nor the lines joining the stars, nor the ecliptic, appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope

Caption: The constellation Corvus with its bright stars and surrounding constellations. Corvus is surrounded by (going clockwise from the top): Virgo, Crater and Hydra. Corvus is a southern constellation and thus the whole of the constellation is visible in the southern hemisphere at some point in the year. The whole constellation is also visible from temperate and equatorial regions of the northern hemisphere. Corvus is best viewed in the evenings in the northern hemisphere late spring and southern hemisphere late 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. The blue line at the top left marks the ecliptic. Neither the constellation boundaries, nor the line marking the ecliptic, nor the lines joining the stars appear on the sky.
Credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope