A naval observatory and hydrographic office was established administratively in the United States Navy in In a hydrographic office was established by statute, and in it was renamed the U. Naval Oceanographic Office. Interest in the charting of oceanic areas away from seacoasts developed in the second half of the 19th century, concurrently with the perfection of submarine cables. As knowledge of the configuration of the ocean basins increased, the attention of scientists was drawn to this field of study.
A feature of marine science since the s has been increasingly detailed bathymetric water-depth measurement surveys of selected portions of the seafloor. Aeronautical charts provide essential data for the pilot and air navigator. They are, in effect, small-scale topographic maps on which current information on aids to navigation have been superimposed. To facilitate rapid recognition and orientation, principal features of the land that would be visible from an aircraft in flight are shown to the exclusion of less important details.
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Centuries before the Christian Era, Babylonians drew maps on clay tablets, of which the oldest specimens found so far have been dated about bce. This is the earliest positive evidence of graphic representations of parts of the Earth; it may be assumed that mapmaking goes back much further and that it began among nonliterate peoples. It is logical to assume that men very early made efforts to communicate with each other regarding their environment by scratching routes, locations, and hazards on the ground and later on bark and skins.
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The earliest maps must have been based on personal experience and familiarity with local features. They doubtless showed routes to neighbouring tribes, where water and other necessities might be found, and the locations of enemies and other dangers. Nomadic life stimulated such efforts by recording ways to cross deserts and mountains, the relative locations of summer and winter pastures, and dependable springs, wells, and other information. Markings on cave walls that are associated with paintings by primitive man have been identified by some archaeologists as attempts to show the game trails of the animals depicted, though there is no general agreement on this.
Similarly, networks of lines scratched on certain bone tablets could possibly represent hunting trails, but there is definitely no conclusive evidence that the tablets are indeed maps.
Many nonliterate peoples, however, are skilled in depicting essential features of their localities and travels. During Capt. In North America the Pawnee Indians were reputed to have used star charts painted on elk skin to guide them on night marches across the plains. Many specimens of early Eskimo sketch maps on skin, wood, and bone have been found. Map cartography.
Written By: Charles F. See Article History. Fomalhaut was also known to the stargazers of ancient Persia as the star announcing the arrival of autumn weather. But unless you live in the southern states or points south, you can forget about seeing the faint stars that compose the rest of this constellation. Although now at their highest point above the southern horizon, more often than not they're too dim to penetrate the haze, which often lies near the horizon.
Fomalhaut usually appears as the one lone star in this very dull and unexciting region of the sky.
In fact, it is sometime referred to as "The Solitary One," because it lies in a rather empty region of the southern autumn sky. Yet it was also an important star to the ancients being one of the four "Royal Stars" of Persia, along with Aldebaran of the wintertime sky, Regulus of spring and Antares of summer. In November and December, when the winter stillness has fallen upon us, a glance toward the southwest will discover Fomalhaut, still placid and alone".
It's often described in various observing books as "reddish," though it is probable that the effects of our atmosphere are responsible for this impression, as this star is always seen at a low altitude for northern observers. Draw an imaginary line southward along the western right side of the Square of Pegasus and three times as far again beyond will bring you to Fomalhaut.
It's believed to be a young star, only about million years old, with a potential lifespan of only a billion years.. Compared to the Sun, it's more than twice as massive, about 16 times more luminous, and more than one and a half times larger. It's one of our closer neighbors in space, at 25 light years away. Fomalhaut is now making headlines because of a recently announced discovery: A new planet has been photographed circling around it.
Back in , a photograph taken by the Hubble Space Telescope provided a detailed visible-light image of a narrow, dusty doughnut-shaped ring around Fomalhaut about 23 billion miles wide. The geometric center of the disk is offset nearly 14 billion miles from Fomalhaut, and offered strong evidence that an unseen planet might be gravitationally tugging on the ring. And last May, University of California, Berkeley, astronomer Paul Kalas was finally able to confirm the existence of that planet in the first ever visible-light snapshot of a world outside of our solar system, a feat announced yesterday.
The planet, now known as Fomalhaut b, orbits its parent star once in years at a distance of 11 billion miles. And Kalas thinks there might yet be other planets in orbits between Fomalhaut b and the star; possibly even a planet that could host liquid water on the surface. The James Webb Space Telescope, a large, infrared-optimized space telescope, scheduled for launch in , might just be able to bring such a planet or planets into view.
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Let us know at community space. All Topics About Us More. The celestial sea covers over a quarter of the horizon, from southeast to southwest. Shown is the evening sky from mid-northern latitudes for this time of year.