Winter sky

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Starry sky in winter for Germany at the end of December at 10 p.m. CET or at the end of January at 8 p.m. CET
Winter sky in mid-January at around 11 p.m. in Münsterland (approx. 51.9 ° N ) with a view to the south - the constellation Orion can be seen above the illuminated tree, Sirius in the center of the picture above the light-polluted horizon.

Winter sky is the part of the night sky , called the on clear winter - evenings can be seen. This view of the sky shows 17 of the 30 brightest stars in the entire sky in Central Europe and depends on it

From the same observation location, 1 month later, we see the same section of sky 2 hours earlier, with each day almost 4 minutes earlier. Because the earth rotates in 23h 56m 04s (a sidereal day ), while our 24-hour day relates to the position to the sun .

For Germany , a mean latitude of 50 ° is usually assumed - the center of gravity of the FRG is 1.2 ° north - and a longitude of 9 ° or 10 ° (near Frankfurt or Würzburg). Almost all rotatable star maps available on the market are calculated for 50 ° / 10 °, which roughly corresponds to the mean for the German-speaking area. For Austria an average of 47.5 ° / 14 ° would be assumed, for Switzerland 47 ° / 8 °.

The picture above right shows the starry sky as it can be seen in mid-January at 9 p.m. CET (mid-February at 7 p.m. CET, mid-December at 11 p.m. CET). The circumpolar constellations around the north celestial pole can be seen all year round. Outside this area, the winter sky hardly overlaps the summer sky , but offers some aspects similar to the autumn sky or the spring sky .

Constellations and constellations

Depiction of star trains in the constellations Orion - with Orion belt - and Taurus, backed by fantasy figures . Its “head” is formed by Aldebaran and the Hyades . Between these and the Pleiades (in a red circle) runs the ecliptic , near which the reddish Mars is also shown here (in the "forehead hair" of Taurus).
Main stars of the constellation Orion : Above, the bright "star shoulder" Betelgeuse left and Bellatrix right in the middle of the eye-catching three belt stars - slightly below the Orion Nebula with the trapezoid - and down the "Fußsterne" Rigel right and Saiph left
Image of the Orion Nebula with a 25 cm mirror telescope

The characteristic constellation of the winter sky is the winter hexagon of 6 stars, 1st magnitude , which also includes the brightest stars of the constellations Orion and Gemini . This area of ​​the sky can be seen in winter in the first half of the night, in June the sun is in this region of the sky. The 3 bright stars of the Orion belt point further to the left to the brightest star in the night sky, Sirius , only about 8.7 light years away in the constellation of the Great Dog . Sirius A is a main sequence star like our daytime star , but about twice as big and hot and 25 times more luminous . His faint little companion Sirius B, on the other hand, is a white dwarf and cannot be seen with the naked eye. The orange-red brightest star in Orion, Betelgeuse "left hand" above the belt, has almost 1000 times the solar radius and is a red giant at a distance of 310 light years.

The five-star row (Perseus-Andromeda-Pegasus) can still be seen high in the west , which has shaped the autumn sky in recent months . It extends from the zenith almost to the horizon and is almost vertical in Central Europe ¹). The constellation Great Bear only slowly rises in the northeast and points with the drawbar down. To the right of this are Leo and Cancer. As a counterpart to the Great Bear, the bright W of Cassiopeia can be seen to the left of the North Star .

The heavenly image of Perseus , who in Greek-Ethiopian mythology belongs to Andromeda and Cassiopeia, stands high above our heads . The bull with the bright star clusters of the Hyades and the Pleiades also stands high in the southwest .

¹) Note: The fact that the five-star row is inclined in autumn (in the eastern sky ) and now almost vertical (high in the western sky) is related to the parallactic angle . Something similar can be observed within a few months on the Orion Belt , which is steep when rising and almost horizontal when setting.

Popular observation objects for binoculars and powerful cameras

The winter sky is not only splendid for free-eyed observation, but also for owners of bright binoculars and for the hobby of astrophotography due to its many star clusters and nebulae . Even for standard glasses (8 × 30, 7 × 50) or for cameras with a small telephoto lens , the constellations Perseus and Orion with their bright nebulae are ideal, as well as the Andromeda Nebula and the large star clusters of the Pleiades and Hyades (both in Taurus) and from February the Praesepe ("Crib", M44) in Cancer.

With greater experience and from around 10 minutes exposure time, numerous nebulae around Orion come within reach (e.g. Horsehead Nebula , Barnard's Loop , Rosette Nebula ), some objects in Gemini and the Milky Way band from there to Cassiopeia.

The latter is also a magnificent sight in binoculars , as are the 3 star clusters mentioned, the Orion Nebula (M42), the double star cluster h / χ Persei and the Andromeda Nebula M31 . Bright, variable stars are also easy to observe, and a. Algol (whose two stars cover each other every 69 hours) and the long-period Mira in the constellation Whale.

Two shooting stars

Two of the brightest shooting stars of the year can be seen in winter : the Geminids meteor shower in December and the Quadrantids in January. Most shooting stars fall in the morning hours from the east, because we then turn with the earth towards them.

Those of the Quadrantids flash between January 1st and 5th. The maximum on January 3rd usually shows a few dozen falling stars every hour that seem to come from the Bear Guardian constellation . On the other hand, the Virginids are only a weak flock .

Planets

In order to enable the visitors of this page to assign earlier planetary sightings, the data of the two previous years are kept in addition to the current year.

Planets in the winter sky 2017/18

  • Mercury has an unusually long free-eyed visibility in the morning sky from December 20 to early February . On January 1st it rises 1¼ hours before the sun, on the 24th it still rises 40 minutes.
It can be seen even better from March 2nd to 20th in the evening sky and is easy to find thanks to the bright Venus: on March 5th / 6th. if it moves 1.4 ° north of the evening star to the east, it has a maximum solar distance of 18 ° on March 15, turns around and meets Venus again on March 18, this time 4 ° north.
  • Venus is currently orbiting far away from the Sun and will only be visible as an evening star in mid-February , initially only in binoculars. In mid-March it sets already 1:20 after the sun and immediately catches the eye in the west.
  • Mars can be seen in the early morning sky and wanders through the constellations Scorpio and Sagittarius in January as a reddish star, 1st magnitude . At the beginning of the year it rises at 3:10 a.m., and at the beginning of March at 2:30 a.m.
  • Jupiter in the morning sky wanders through Libra to the left, where on January 3rd it forms a beautiful pair with its main star Zuben-el-dschenubi . On 9.3. he turns to the right and starts his opposition loop this year. It rises in the southeast at 3:25 a.m., and at midnight in early March. In May he comes into opposition and can then be seen all night. The delightful interplay of Jupiter's moons is then enriched with close mutual conjunctions.
  • The ring planet Saturn in the constellation Sagittarius appears in the middle of January at dawn. In mid-February it rises at 4:40 am CET in the southeast (2¼ hours before the sun), and in mid-March at 2:50 am.
  • For the Uranus , discovered in 1781, you need at least a small pair of binoculars. It wanders slowly through the fish and stands in the evening sky until the beginning of March, then beyond the sun.
  • The outermost planet Neptune in Aquarius can only be observed (in the telescope) until the end of January at dusk.

For early risers there are delightful planetary encounters with the morning crescent moon on January 11th (Jupiter and Mars) and on the 15th with Saturn. In the following month, these conjunctions are on February 7th, 9th and 11th. The three bright planets demonstrate the ecliptic plane to the exact degree .

Among the minor planets , Ceres, discovered on December 31, 1800, comes into opposition to the sun at the end of January , but this time only reaches 8th magnitude.

Planets in the winter sky 2016/17

  • Mercury is freiäugig not until January to late evening twilight freiäugig visible in the southwest, and from mid-March in the evening sky.
  • Venus has been a shining evening star since late autumn . In January it sets 2–3 hours after the sun, in February only 3–4 hours. On March 25th, she has the lower conjunction in front of the sun.
  • Mars can be seen in the evening as a reddish star of the 1st magnitude in the south to the southwest. At the beginning of March it can be found at the point where Venus is 1 hour before. As a result, its brightness decreases to 2nd size .
  • Jupiter in Virgo rises at 1 a.m. in the New Year, and at 10 p.m. in mid-February. At the beginning of April it comes in opposition to the sun and is then visible all night.
  • Saturn in the Serpent Bearer and Libra is initially only visible in the early morning sky. In mid-January it rises at 5:30 am CET and in mid-March at 2 a.m.
  • Uranus in the constellation Pisces is in the evening sky from January to early March, then beyond the sun. At first, when the sky is clear, it can only be easily seen, but in the telescope it shows a small greenish disc.
  • The outermost planet Neptune in Aquarius can be observed (in the telescope) in the evening until the beginning of February.

Of the larger asteroids , (4) Vesta and (1) Ceres can be seen in particular . Vesta has on January 14th and 19th close encounters with a star 6th mag in Cancer and on 4.2. with Kappa Gemini. In addition to these two minor planets discovered in 1807 and 1800, (9) Metis, (14) Irene, (15) Eunomia and (29) Amphitrite are brighter than 9th magnitude.

There are bright star occultations by the waxing moon (i.e. in the evening). a. on 5.2. (70 Tauri and Theta Tauri , both in the star cluster of the Hyades ) from 5:40 p.m. to 7:10 p.m., as well as on 4.5. at 10:02 pm ( Gamma Tauri ).

Planets in the winter sky 2015/16

  • Mercury is freely visible in the southwest from Christmas to January 6 at dusk , and in the morning sky from February 25 to 10.
  • Venus is the shining morning star until mid-March . At the beginning of the year it rises 3 hours (4:40 CET) before the sun, at the beginning of March only 1 hour.
  • Mars can be seen in the second half of the night in the east as a reddish star of the first magnitude . At the beginning of December it was close to Venus and Jupiter and is now moving through the constellations Virgo, Libra and Scorpio.
  • Jupiter in Leo rises at 10pm on New Year's Eve, and at 8pm in mid-February. On March 8th, it comes in opposition to the sun and is visible all night. In amateur telescopes one can now observe changing constellations and eclipses of the moons of Jupiter almost daily
  • Saturn in the Serpent Bearer is initially only visible in the early morning sky. In mid-January it opens at 4:40 CET, and in mid-February at 2:50.
  • The open -eyed Uranus in the constellation Pisces is in the evening sky until the beginning of March, then beyond the sun.
  • The outermost planet Neptune in Aquarius can be observed (in the telescope) in the evening until around February 15.

The delightful planetary encounters from 6./7. November and 4th / 7th December with the morning crescent moon now take place at longer intervals: In January from 1st (Jupiter) and 3rd (Mars) to 6th (Venus), one month later with the crescent between January 28th and February 6th, 2016. The three bright planets demonstrate the ecliptic plane to the exact degree .

You can also see the "Christmas Comet" Catalina (C / 2013 US10), but only in binoculars. In February it wanders with decreasing brightness (6.5 to 8 mag) from the vicinity of the Pole Star in the direction of the constellation Perseus , and in March further to the Capella , the highest (near zenith) star of the winter hexagon .

Seasons

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