Summer sky

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Starry sky in summer for Germany at the end of June at 11 p.m. CEST or at the end of July at 9 p.m. CEST

Summer sky is the part of the night sky , called the on clear summer - evenings can be seen. That sight of heaven depends

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-July at 9 p.m. CET (in summer time : 10 p.m. CEST) (mid-June at 11 p.m. CET or 12 p.m. CEST, mid-August at 7 p.m. CET or 8 p.m. CEST). The circumpolar constellations around the north celestial pole can be seen all year round. Outside of this area the summer sky hardly overlaps with the winter sky , but offers some aspects similar to the spring sky or the autumn sky .

Constellations and constellations

The most striking constellation is the large summer triangle rising in the east , which consists of 3 stars of the 1st magnitude and runs around the constellation of the swan (northern cross). Its cornerstones are Vega in the lyre (brightest star in the northern sky), Deneb in the swan and Altair in the eagle.

Sagittarius and Scorpio are located deep in the south and southeast , where the center of our Milky Way lies over 25,000 light years away . This stretches as a delicately shining band with many star clusters and nebulae over lyre and swan north to Cassiopeia . In Scorpio and Sagittarius the sun is at the beginning of winter, so that these constellations can now be seen in the sky in the first half of the night for a few hours in summer. The scorpion's claws converge in the red star Antares (Greek for “countermars”) - a red giant with 700 times the solar radius , which, however, is only in 18th place of the bright stars due to its distance of 520 light years. In the summer of 2007 he formed a striking pair of stars with the golden yellow “royal star ” Jupiter . Antares is only 4 ° south of the ecliptic and is therefore covered by the moon several times a decade .

To the right of this are the scales through which Jupiter passed in 2006. In 2008 it is already in Sagittarius, on July 9th exactly opposite the sun and rises when it sets. Further to the west, the Virgo and the Lion can be seen, who have shaped the spring sky in recent months . The bright constellation Leo is enriched this year by the red planet Mars and the ring planet Saturn . The big wagon is steeply above it - but unlike in winter it now has the drawbar up. In the west, the constellation Cancer has already set, but when the horizon is flat you can still see the capella (carter) sparkling deep in the NNW .

As a counterpart to the Big Dipper (Big Bear), to the right of the North Star (a little lower), the bright W of Cassiopeia is noticeable, and part of the five-star row with the Pegasus autumn square is already rising above the northeast horizon. The long curly sky dragon stands high above our heads and opposite Hercules , who is his conqueror in Greek mythology.

If you want to go on a “fog hunt” with a good pair of binoculars , the constellations Snake Bearer and Sagittarius are recommended . Where the snake winds in front of its "bearer" (the mythical doctor Asklepios ), there are some bright globular clusters . The Sagittarius is still low, but offers (top right) a rich palette of nebulae: spherical and open star clusters , dark and radiant gas nebulae . In Hercules (right side of the square) one can easily see the very bright globular cluster M13 , and above the Andromeda the spiral nebula of the same name M31 . In a few weeks it will be high enough to be able to see it freely as a little cloud.

Shooting stars

From mid-July, the first harbingers of the Perseids , the most famous and second strongest meteor swarm of the year , appear in the morning hours . It reaches its striking maximum on August 11th and 12th, but then the number of shooting stars drops rapidly. The radiant shifts over the course of the weeks from Perseus to Cassiopeia ("Himmels-W").

The mostly very bright, but only grain of sand-sized meteoroids have a high speed of ~ 60 km / s and therefore hardly flash for seconds when entering the air envelope. However, the often rumored fall rates of 60–120 meteors per hour only apply to ideal conditions in high mountains or in dry deserts; in Central Europe it is around 20 to 40 an hour in the second half of the night, and around half as many a week before and shortly after the maximum. In some years such as 2009, when the maximum is close to the full moon , the weaker falling stars disappear in the brightened sky background. Its body of origin is comet 109P / Swift-Tuttle .

The July aquariids between July 25th and August 10th are less prominent with a sharp maximum on August 3rd , which apparently come from the constellation Aquarius .

On the other hand, the cygnids can stay on the observation program for a very long time . They have their radians in the swan and can be seen between July 25th and September 8th (flat maximum around August 16th ). The planetary current has a somewhat weaker branch around August 18th, the so-called Cepheids - not to be confused with the pulsating giant stars , which are so important for the intergalactic determination of distance.

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 summer sky 2019

  • Mercury bare-eyed in the evening at the end of June, visible in the morning in August; telescopic even in the daytime sky
  • Venus in the morning sky until mid-July, then freely-eyed invisible (evening star from October)
  • Mars invisible (beyond the sun)
  • Jupiter in the Serpent Bearer: in July all night, from August / September first half of the night. In August it shifts its sets from midnight to 10 p.m., but is in the evening sky until October .
  • Saturn in Sagittarius: Opposition to the sun on June 27th, therefore visible all night. Setting in late August at 1 a.m. The rings of Saturn can be seen wide open these years.
  • Uranus in Aries and Neptune in Aquarius: first seen in the second half of the night, later almost the whole night - but only in the telescope as small, green-blue discs.

Planets in the summer sky 2018

  • Mercury is free-eyed only from August 20th. until 10.9. visible, a maximum of 1 hour before sunrise; telescopic even in the daytime sky
  • Venus is evening star until the end of September . It is at its greatest brightness in mid-September, but is already deep in the west
  • The red planet Mars is located deep in the south in the constellations Sagittarius and Capricorn. His opposition on July 27th is the closest to earth until the year 2033 and already shows some details of the surface in amateur telescopes . In July and August, Mars even becomes a little brighter than Jupiter, which is 20 times larger and can still be seen in the southwest.
  • Jupiter is in Libra. In August it shifts its sets from midnight to 10 p.m., but can be observed in the evening sky until October . One month later he comes into the annual conjunction with the sun
  • Saturn in Sagittarius will reach its opposition to the Sun on June 27th and will be in the deep southeast or southern sky in the evening. At the end of July it sets at 3h CEST, at the end of August at 1 a.m. The rings of Saturn can be seen wide open these years.
  • Uranus in Aries and Neptune in Aquarius can be seen in the second half of the night - but only in the telescope, where they show a small, green-blue disc.

Of the ten brightest minor planets , Ceres, Vesta, Hebe and Astraea can be observed temporarily in a small telescope.

Planets in the summer sky 2017

  • Mercury is invisible to the naked eye and can only be seen in the morning sky in September .
  • Venus has been the shining morning star since April and will remain so almost until the end of the year.
  • Mars does not emerge from dawn until early September; Rising at the end of July at 5:20 am daylight saving time.
  • Jupiter (in Virgo) is in the evening sky until the end of September . At the end of July it sets at 11pm CEST.
  • Saturn (in the snake bearer) can initially be seen all night, later only in the evening.
  • Uranus (Pisces) and Neptune (Aquarius) are telescopically visible most of the night.
  • Pluto in Sagittarius can only be seen in very large telescopes.

Planets in the summer sky 2016

  • Little Mercury can initially be found behind the sun and not until the end of July with good binoculars at dusk. It sets 55 minutes after the sun, but a few degrees south. You can only see him freely from September 20th in the morning, a maximum of 1/2 hour before sunrise (elongation ~ 15 °). Telescopically , however, its tiny disc can almost always be observed in the daytime sky .
  • The "love star " Venus also stands far beyond the sun at the beginning and will not be visible as an evening star until the end of July at the earliest . In August its elongation (distance from the sun) increases from 15 ° to 23 °, but it sets 40 to 50 minutes after the sun, in September by 1 hour. Only in autumn will the visibility increase to 2 hours.
  • Deep red Mars was in opposition to the sun at the end of May, but deep in the south. It wanders from the constellation Libra to Scorpio and culminates at around 10 p.m. CEST at the end of June and at 8 p.m. at the end of July. After that, it can only be seen at dusk deep in the southwest.
  • The giant planet Jupiter is located in the constellation Leo and can be observed in the evening sky until mid-August . One month later he comes into the annual conjunction with the sun.
  • The ring planet Saturn stands between the scorpion and the serpent bearer and is initially deep in the south at midnight, about 15 ° to the left of the brighter Mars. But in mid-August it sets in the southwest at midnight, and in mid-September at 10 p.m.
  • Uranus (in Pisces) and Neptune (in Aquarius) are in the morning sky from July, but are only visible in the telescope. The best time to observe the small discs (3.5 "or 2.5") is around midnight in September in the southeast or in the south, about 40 ° high. While a pair of binoculars with a simple star map is sufficient for Uranus , a telescope with partial circles or a GoTo mount is advantageous for Neptune .

Of the ten brightest minor planets , Flora, Vesta, Parthenope, Pallas and, most recently, Ceres can be observed in a small telescope. There is even a star occultation in July .


News from the sun

Our star of the day is no longer considered a planet since Copernicus (“roaming around”), but a short paragraph for 2017 is dedicated to it. The solar activity should, according to initial predictions since 2013 subside (eleven years cycle), but it did relatively slow. It has sometimes been spot-free since 2016, but this summer often shows relative numbers up to around 70 (15–30 sunspots ). At the end of August even a huge group of type F spots rotated over the eastern edge and reached the middle of the sun on September 4th , where it will show over 100 individual spots with a second, similarly large group.

With a suitable solar filter you can even see these two groups with bare eyes.

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