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Astrolabe - what is this device, how to do it yourself

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Our author's teaching materials on ornithology and birds of Russia:
In our online store at non-commercial prices (at the cost of production)
can to acquire the following teaching materials on ornithology and birds of Russia:

computer digital (for PC-Windows) Guide to birds of Russia, containing descriptions and images of 206 species of birds of the middle lane (drawings of birds, silhouettes, nests, eggs and voices), as well as a computer program for identifying birds encountered in nature.
application for smartphones and tablets Android Field guide to Russian birds (you can buy it in the Google Play store),
iPhone and iPad applications: Birds of Russia, Birds of Europe, Russian Birds Voices, Bird Calls: Birds of Europe, Bird Calls: Birds of North America: Decoys, Field Automatic Bird Voice Recognition (all of them can be downloaded from the AppStore),
pocket field guides Birds of the middle lane (160 species), Birds of Russia (278 species),
colored identification tables Migratory birds, Wintering birds,
identification books of the series "Encyclopedia of the Nature of Russia": Birds, Pets,
MP3-disks with the voices of birds (songs, calls, calls): Voices of birds of central Russia (343 species) and Voices of birds of Russia, part 1: European part, Ural, Siberia (BN Veprintsev's music library, 450 species).

Marsh warbler, or swamp robin (obsolete) - Acrocephalus palustris

Appearance. In the field, it is practically indistinguishable from reed warbler, although the uppertail is not reddish, but olive, the legs are light pinkish, the claw of the hind toe is shorter than the toe itself.

Vote. (Reload the page - F5 to listen to the voice again). The song is more musical, with canary trills, individual sounds are usually not repeated. Shout - a sharp "check-check-cherr".

Habitat. Inhabits weeds, coastal shrubs, forest edges and clearings.

Food. It feeds on insects.

Nesting places. Nests in bushes and tall grasses. But it is most numerous on the shores of reservoirs. It also nests on forest edges, clearings, in overgrown gardens.

Location of the nest. The nest is arranged far from water, in thickets of bushes, nettles and other plants, as a rule, no further than 2-3 m from the edge.

Building material of the nest. A suite of stems and leaves of cereals and other herbaceous plants, thicker on the outside and thin on the inside. The outer layer is loose, the inner layer is dense and made very carefully. The tray is often lined with bindweed hairy whiskers, horsehair, and sometimes wool.

The shape and size of the nest. The nest has the shape of either a basket, or a low cylinder with a rounded bottom, or a cone pointed at the bottom. The inner edges of the tray are tightened so that the diameter of the upper opening of the tray is smaller than the width of its inner cavity. The entire structure is suspended by its upper edges from several vertical stalks of grass or shrub branches, usually at a height of 0.3-0.8 m from the ground. Nest diameter 80-120 mm, nest height 50-130 mm, tray diameter and depth 40-60 mm.

Features of masonry. Clutch of 4-7 white or greenish-white eggs with deep violet-gray fields and various sizes of olive-brown surface spots and small blackish specks. Egg sizes: (17-20) x (12-15) mm.

Breeding dates. Arrives in May. Begins to lay eggs in the first half of June. Chicks hatch in the second half of June, and fly out of the nest in the first half of July. Departure takes place in August.

Spread. Distributed in the middle zone and in the south of the European part of Russia, in the Caucasus. In Central Europe - from May to October.

Wintering. Winters in Africa.

Description of Buturlin. From a distance, this bird cannot be distinguished from garden warbler... She has the same olive brown in the summer coloration top and whitish or yellowish bottom. The dimensions are approximately the same. Systematic differences lie in the wing formula, that is, in the ratio of the length of the flight feathers.

And in terms of lifestyle and habitat, these are well-differentiated birds. Already one singing enough not to mix the marsh warbler with the garden warbler. She, too, is a good songstress and is good at picking up other people's voices, but she connects all sounds together in a hasty, even as if choking, tongue twister. All the “words,” both his own and those adopted, are strung together one after the other (but also repeated 3-4 times), and the singer chirps, whistles and chirps sometimes for a very long time, as if not daring to stop. The singing warbler pose is very interesting. Stretching out, inflating the neck with a pea and opening his beak incredibly wide, the singer is shaking all over with strain and excitement. Indeed, if you listen to the warbler very close (for example, hiding in a bush), then you are involuntarily surprised by the strength of the voice of this small and gentle bird. But you move a little in your ambush - the singer suddenly becomes silent and, sharply shouting: “Chrek. chrek. ”, Sneaks into the thicket further away. In different localities, the imitative sounds in the song of marsh warblers are not the same.

The marsh warbler in the European part of Russia is not found as far north as the garden warbler, but to the south distributed to the Caucasus and Crimea (intermittently). The northern border runs approximately through the middle course of the Volga and Ural rivers near Sverdlovsk. In Western Siberia, this warbler is distributed to the headwaters of the Yenisei River, and to the south through Central Asia to Iran. Wintering grounds are found mainly in Africa (to the very south).

This warbler is more attached to wet places and the banks of water bodies than the garden warbler. Beloved places Its summer habitat is dense willow thickets, usually stretching along the banks of small rivers or forming islands among damp flood meadows (often near oxbows and drying bogs). Here sometimes a couple from a couple nest at a distance of several meters, and, walking along the coast, you do not have time to pass one singer, as you are already approaching another. Frequent neighbors of marsh warblers are here shrike shrikes, lentilsand sometimes also reed buntings and hawk-warblers... Here, in the thickets, warblers find themselves rich food and rarely fly out of them, only to the water in reeds (for mayflies, caddis flies or to a watering hole) or to the edge of a flood meadow - to grab a gape fly.

The study nutrition marsh warblers (according to stomach contents) shows that they eat mainly naked caterpillars (up to 60 percent of food), then various mosquitoes, as well as small leaf beetles and ladybirds. By exterminating harmful leaf beetles, these warblers bring undoubted benefits, which are not destroyed even by their addiction to useful ladybirds.

Nest it is mostly nestled low, no more than a meter from the ground. Its one female Viet, it takes several days to build. A full clutch contains 5-6 testicles (18-19 millimeters long). Their main pale bluish or greenish background is covered with olive-brown small specks and deeper grayish spots. One female incubates and in the end it is so stubborn that sometimes you can even take it with your hand. While worrying about the nest, the birds scream hoarse “chrr. chrr. ”And dart very close in the branches. They bring many naked caterpillars and small dipterans to their chicks. Ten to twelve days after hatching, the chicks are already out of the nest, first on vertical stems above it, and then silently hiding nearby in dense thickets of grass, nettle or willow. Here they hide until they start flipping around.

The marsh warbler rarely makes two clutches in summer. In early September, she already flies away from the central strip, and by October departure ends throughout the European part of Russia.

Species descriptions taken from Keys to birds and bird nests in central Russia (Bogolyubov A.S., Zhdanova O.V., Kravchenko M.V. Moscow, "Ecosystem", 2006).

Our author's teaching materials on ornithology and birds of Russia:
In our online store at non-commercial prices (at the cost of production)
can to acquire the following teaching materials on ornithology and birds of Russia:

computer digital (for PC-Windows) Guide to birds of Russia, containing descriptions and images of 206 species of birds of the middle lane (drawings of birds, silhouettes, nests, eggs and voices), as well as a computer program for identifying birds encountered in nature.
application for smartphones and tablets Android Field guide to Russian birds (you can buy it in the Google Play store),
iPhone and iPad applications: Birds of Russia, Birds of Europe, Russian Birds Voices, Bird Calls: Birds of Europe, Bird Calls: Birds of North America: Decoys, Field Automatic Bird Voice Recognition (all of them can be downloaded from the AppStore),
pocket field guides Birds of the middle lane (160 species), Birds of Russia (278 species),
colored identification tables Migratory birds, Wintering birds,
identification books of the series "Encyclopedia of the Nature of Russia": Birds, Pets,
MP3-disks with the voices of birds (songs, calls, calls): Voices of birds of central Russia (343 species) and Voices of birds of Russia, part 1: European part, Ural, Siberia (BN Veprintsev's music library, 450 species).

In section Nature in photographs also hosted thousands scientific photographs mushrooms, lichens, plants and animals of Russia and the countries of the former USSR, and in the section Natural landscapes of the world - photographs of nature in Europe, Asia, North and South America, Africa, Australia and New Zealand and Antarctica.

In section Methodical materials You can also get acquainted with the descriptions of the printed identifiers of plants in the middle lane, pocket identifiers of natural objects in the middle lane, identification tables "Mushrooms, plants and animals of Russia", computer (electronic) identifiers of natural objects, field identifiers for smartphones and tablets, developed by the ecological center "Ecosystem" , methodological manuals for organizing project activities of schoolchildren and field environmental research (including a book for teachers "How to organize a field environmental workshop"), as well as educational films on the organization of project research activities of schoolchildren in nature. Purchase all of these materials are available in our non-commercial online store. You can also purchase there mp3 discs Voices of birds of central Russia and Voices of birds of Russia, part 1: European part, Ural, Siberia.

Astrolabe and its purpose

Since ancient times, people began to need devices to help them navigate in space. They were necessary for navigators, travelers, clergymen, merchants to return home from distant wanderings, astronomers to study celestial bodies, coordinates of objects.

Ancient astronomers called an astrolabe a device for measuring the latitude and longitude of the point of finding objects, celestial bodies. He made it possible to determine the height of the location of the stars, the Sun above the surface of the planet Earth, and also, thanks to the data obtained, calculate the location. During travels, such a product served as the only reference point for determining coordinates, time of day. In short, the astrolabe has become one of the oldest measuring instruments invented by people in ancient times.

In different centuries, it has been used as:

  • clock,
  • rangefinder,
  • navigator,
  • counting machine,
  • reference book of coordinates,
  • atlas of trigonometric functions.

Astrolabe video review

Treatises in different languages ​​of the world were dedicated to her, poems were composed, pictures were drawn. Such an astronomical instrument was a valuable gift for kings, kings, sultans, aristocrats.

Origin story

It is surprising that the beginning of the construction of the device was the time of the geocentric vision of the picture, when it was believed that all celestial objects revolve around the Earth. But this did not prevent scientists from constructing a model of such an accurate device for measurements.

The basis of the name of the astronomical instrument is the word "astra". If translated from Greek - "star". The second part is translated as "capture". Many elements have Arabic terms. The reason is the long evolution of the measuring device.

Originally from antiquity

The development of astronomy, together with other sciences, is closely related to the history of Ancient Greece. It is believed that almost two centuries before the beginning of our era, the prototype of the product created by Hipparchus was used here. In the second century, a similar goniometric instrument was described by Claudius Ptolemy. He also made a device capable of determining the location of stars in the sky.

Who invented

Usually astrolabes were made from wood, an alloy of copper and zinc. It is unknown who invented the metal astrolabe. It is only certain that the first such device existed already in the 4th century. It was made, most likely, by the last ruler of the famous library of Alexandria, Theon of Alexandria.

Improvement

The Arabs quickly appreciated all the advantages of the design and expanded the scope of the astrolabe. They began to use it for mathematical calculations, predictions of astrologers. Western Europeans have been using the device since the 12th century. But the peak of his popularity fell on the Renaissance, when astronomical knowledge was considered the basis of education, and the ability to use an astronomical instrument was prestigious.

The decoration turned the device into a collectible at the royal courts. Models were decorated with inlaid with precious stones, decorated with gold and silver. Pointers were made like leaves, fancy curls.

Stereographic projection - turning a sphere on a plane

The operation of the astronomical device is based on stereographic projection. Any round object of the celestial sphere during planispheric projection remains circular on the plane, and the magnitude of the angles is preserved. This principle of depicting a sphere on a flat surface is an invention of the ancient Greek mathematician Apollonius of Perga.

How the astrolabe works

With the help of the device, the difference in readings between the horizon and the direction to a celestial object is recorded.Taking into account local time, special tables determine the latitude of the location of the point. Ancient items were hung vertically with a ring. Through an alidade equipped with diopters, the stars were observed, whose heights were measured on a scale. Later, the device turned into a geodetic device for measuring the magnitude of the angles of the horizontal plane, shooting plans of the area.

What parts does it consist of

The astrolabe of Theon of Alexandria, like all subsequent models, included:

  • frame of the entire structure,
  • disks - "tympans" containing the marks of the horizon lines, meridians, circles of equal heights and azimuths,
  • a system of celestial coordinates with a pole of the world, a zodiacal circle with a set of stars, whose position was fixed by pointers,
  • alidada with a vizier for observing the stars and celestial bodies,
  • The whole structure was fastened with an axis.
  • Different engravings on the scales made it possible to calculate the position of celestial bodies, different throughout the day and throughout the year.
  • Sometimes the models were equipped with scales with additional information.

What Astolabia is like

The design is similar to a "plate" with different grooves, small elements, gear, degree markings. At the heart of the classic astrolabe is a round disc with a high rim, a ring for accurate leveling. On the outside, on the limb, there is a scale digitized in degrees, hours, minutes. Most often, astrolabes were made in small sizes, so that it was convenient to pick them up and use them for navigation.

Where was it applied

The functions of the device are so diverse that it can be considered a stargazer's computer. Back in the 10th century, al-Sufi, in a treatise of 386 chapters, described almost 1000 options for the field of application of the astrolabe.

Perhaps the Arab scientist somewhat exaggerated the capabilities of the products, but with their help:

  • the coordinates were recalculated,
  • the direction vector was determined through the sight,
  • the time was specified,
  • horoscopes were built,
  • the depths or heights of earthly objects were measured,
  • trigonometric functions were calculated.

Other types of astrolabes

The designs of astronomical items were made according to the measurement purposes.

  • spherical,
  • shuttle-like,
  • observant,
  • linear,
  • sea.

Craftsmen also made universal designs.

How to use

In the wording of the definition of what an astrolabe is, there is no description of how measurements are taken correctly, because the process does not require special skill.

  • First, the height of the Sun or one of the brightest stars is measured. The ruler shows the result.
  • By rotating the "spider" mesh, the ecliptic points coincide with the image of the small circle of the celestial sphere.
  • When used correctly, a stereographic image of the sky appears on the front surface, allowing the scale to calculate coordinates.

Where you can see and buy an old instrument

You can see unique products in museums, private collections, observatories. The history of each of them is amazing. A wooden model has survived, made shortly before the overthrow of the Safavid ruler Soltan Hussein I. The Hermitage keeps such unique devices as a trophy astrolabe brought after the Russian-Turkish war of the 18th-19th centuries. The inscriptions on it are made in Persian and Arabic script, the numerical values ​​are written not in numbers, but in cursive.

The same instrument is on display in the London Museum, and the model of the 16th century is the property of Germany. Its author Johannes Pretorius decorated the product with engravings, details of mesmerizing beauty. Today, different models can be bought online, through souvenir shops, museums, from artisans, at virtual auctions.

How to make an astrolabe with your own hands

It is not easy to make an accurate measuring instrument on your own, because you need mathematical knowledge, drawing and calculation skills. After all, the reliability of the result depends on the accuracy of the specified parameters.

The simplest model of an astrolabe with your own hands can be made from cardboard. For manufacturing, you need to stock up:

  1. compass,
  2. protractor with an arc of 7.5 cm,
  3. plexiglass or a piece of plywood,
  4. brass strip 2-3 cm wide.

  • At the beginning of making an astrolabe, you need to cut out a disk with a diameter of 14-15 cm from plywood for a dial (dial). The markings will be two protractors glued to the surface of the circle.
  • Then prepare the target plate made of brass strip for installation. Its length should be 5-6 cm more than the diameter of the disc. Its ends, protruding beyond the edges of the disc, should be bent upward at an angle of 90 degrees, sawed through holes in them.
  • On the horizontal part, drill two wider slots through which you can see the readings of the dial.
  • They should be located symmetrically to the center of the plank. Attach the center of the finished target plate to the center of the disc using a bolt, washer, nut.
  • It should rotate freely in the horizontal plane. Glue the compass to the center of the sight.
  • For measurements, the targeting bar is directed towards the Sun, which should be visible through the slits of the bar on the sides.
  • The azimuth of the luminary is the ratio of the protractor markings in degrees to the compass north pointer.

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