Star chart

A star chart is on a map again the position of the stars and constellations in the sky. Often the brightnesses of stars are represented by signatures.

A related set of star charts that map the entire night sky, called star atlas. Older atlases are limited partly due to the northern sky.

Early depictions of the starry heavens

Recognized as the oldest representation of entire constellations are ancient Egyptian figures in the grave of Senmut. In earlier representations of stars, such as the sky disc of Nebra, the stars are ( with the exception of one group, which probably represents the Pleiades ) was probably distributed by the artist rather random. Apart from murals of the ancient world still celestial globes and planispheres known, which was partially related to the ornamental, but also for astronomical work.

The development of the cards is accompanied by the creation of star catalogs. Ptolemy describes both the construction of celestial globes as well as of planispheres ( rotating star charts ). Planispheres have not been preserved, but Carolingian copies of the constellation description of Aratus contain planispheres and representations of individual constellations, which were probably copied from ancient originals. These maps show but only the constellations, not the individual stars. From the 9th century there are more and illustrations of the constellations, especially as part of copies of the Poeticon Astronomicon of Hyginus, which is the standard source of the Middle Ages to the myths of the constellations. These representations translated but stars, if they are ever with mapped positions of imagination, which fit to the image.

Historic Star Maps

For a long time almost only cards of the individual constellations were published, the positions of which they were based mostly on the obsolete Greek data by Ptolemy and Hipparchus ( whose catalog is lost during the early Middle Ages in the West went ) if they do not do free-hand drawn. Although Ptolemy's catalog in the Arab world and Byzantium was saved, but only with the measurements of astronomers such as Tycho Brahe were modern positions available that very quickly evolved into the standard.

1515 published the first printed planispheres by Albrecht Dürer, John Stabius and Conrad Hein Fogel, who showed the entire sky on two cards: the hemispheres north and south of the ecliptic.

1535 a Hyginus edition was published with stars indicate the approximate positions and lines of a graticule in Cologne and 1570 appear with Alessandro Piccolomini's De le stelle fisse star maps that show only the stars in approximately correct positions and renounce the figurative representation of the constellations.

Johann Bayer finally published with the Uranometria 1603 the first atlas of the entire sky rather than a collection of maps of selected constellations or less accurate planispheres. The positions in the Uranometria based on observations of Tycho Brahe, who was famous for his observation accuracy. The individual cards are but still tailored in size to the constellations shown, so that there is no uniform standard. As an artistic masterpiece of sky atlases applies Andreas Cellarius ' Harmonia Macrocosmica from 1661, although scientific and cartographic lagged detailed works such as the Uranometria, but summarizes colored on unparalleled engravings the astronomical knowledge of the time vividly.

However, the actual representation of the sky evolved in both scientific and artistic point on, until in 1801 appeared the Uranographia of JE Bode. The atlas consisted of 20 cards in the format of 103 × 70 cm and is so far the largest Atlas in the format. The engravings are very delicate and rich in detail and show approximately 17,000 objects of the fixed stars.

Because of this wealth came increasingly to depend on to represent the constellations figurative, and was limited to the drawn lines connecting the main stars. Even the latter appear today only in popular science cards.

Today's Star Maps

Drawn maps, ie representations of a catalog which can be used professionally only for limited purposes today, but remain important popular and amateur astronomical work equipment. Otherwise, the catalogs are either just yet published, from which you can print outs as required, or photographic cards, arising directly from telescopic images, such as the Digitized Sky Survey.

Numerous people today use but rather astronomical planetarium software, which often includes extensive star catalogs.

When stargazing outdoors using rotating star maps ( planispheres ).

Believed to be a star map for angle measurements are, the stereographic projection is usually selected. On it are all the curves intersect at the same angle as on the celestial sphere ( conformality, and, moreover, applies general circuit loyalty ).