DE9015494U1 - Celestial globe - Google Patents

Description

tat i_ o TJ-^-&iacgr;-^&Lgr;&Lgr; D-8000 MUNICH

Weber & Heim - ¹ ' Hofbrunnstrasse

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European Patent Attorneys Fax: (0 89) 7 91 52

Celestial globe P 261

The invention relates to a transparent celestial globe.

As is well known, a celestial globe is used to depict the starry sky on a spherical surface. The visualization of the starry sky in the form of a sphere is based on the impression (which does not correspond to reality) that all astronomical objects (celestial bodies) are located on the inner surface of a hollow sphere, in the middle of which the observer is located. This apparent hollow sphere is divided by the horizon into two hemispheres, the sky above the horizon that is visible at the moment of observation and the area that is invisible to the observer, including the stars that have already set or have not yet risen.

The daily rotation of the earth around its axis results in the impression (which does not correspond to the actual circumstances) that this celestial sphere rotates around its own axis, namely around the so-called celestial axis that runs through the north celestial pole, the observation point on the earth (center of the horizon circle) and the south celestial pole.

Although the moon, the sun, the planets and the fixed stars are at very different distances from the earth and thus not on the inner surface of an imaginary hollow sphere, even the closest of these celestial bodies is so far away from the earth that the human eye loses any impression of perspective. A celestial body is too

at the same time always at the same place on this apparent celestial sphere, regardless of where on Earth the observation is made. The parallax that occurs is so small that it can only be detected with optical aids.

Although celestial globes do not represent the actual astronomical conditions, but only reflect the apparent impression that the human eye receives when observing the sky, they serve both purely decorative and very practical purposes. In principle, they can be used to demonstrate the apparent daily movements of the stars, including the apparent course of the sun through the zodiac, which depends on the season, for example, with their different heights above the horizon and with the different rising and setting positions, deviating from the east-west direction. Celestial globes therefore serve in general to illustrate astronomical processes. In this context, they also serve as a model for teaching the basics of astronomical navigation. Planetariums also depict the apparent astronomical processes described.

Celestial globes depict the starry sky in mirror image, corresponding to an observation of the apparent celestial sphere from the outside. They can also have astronomical auxiliary lines on their surface in the form of a coordinate network, including the celestial equator, the north and south celestial poles, the zodiac, etc. Celestial globes made of both transparent and opaque material are known. The division into the visible upper and invisible lower celestial hemispheres can be indicated by a horizontal ring corresponding to the horizon and fixed outside the rotating sphere.

As with terrestrial globes, a distinction is made between rolling globes and rotating globes. The former are freely movable spheres that can be rotated around any axis within a frame, e.g. with a different alignment of the celestial axis. However, the rolling globe is only partially suitable for demonstrating the daily apparent rotation of the celestial sphere with the stars around the celestial axis, as it does not have a fixed axis and both the rotation around the celestial axis and the alignment of the same can only be achieved manually with insufficient precision.

Rotating globes, on the other hand, are mounted on a fixed axis that corresponds to the celestial axis. In some known designs, the inclination of this axis is adjustable, so that the position of the observer, which results from the geographical latitude, can be simulated here as with a rolling globe - albeit with much greater precision. (Inclination of the celestial axis against the horizon = geographical latitude.)

The disadvantage of the known designs of celestial globes described in these demonstrations and simulations of astronomical phenomena is that they require a certain degree of abstraction from the user. This abstraction is necessary because, in contrast to the situation in real sky observation, the known celestial globes are a hollow sphere.

The fixed horizontal ring that is present as the "horizon" in some known versions of celestial globes outside the rotating, spherical part only provides approximate information about which stars are above the horizon. In order to achieve at least a certain degree of precision in the corresponding statement,

the observer's eye must be at the height of this outer horizon ring and, to a certain extent, aim at the horizon plane on the globe's surface. But even then, the stars below the horizon remain just as visible as those above the horizon.

The object of the invention is therefore to create a celestial globe of the type mentioned at the beginning, which allows the stars located above the horizon to be reproduced more clearly without disturbing influences.

This task is solved by arranging a plane in the sphere cavity that automatically aligns itself horizontally and runs through the center of the sphere.

The basic idea of the invention is to create a visible dividing surface as a circular "horizon disk" between the upper and lower hemispheres of the celestial globe. In this way, a clear distinction is possible between celestial bodies that would actually be visible or invisible to an observer on earth. The invention has the advantage that, on the one hand, the visible celestial hemisphere is realistically visible above the horizon disk and, on the other hand, the rising and setting of celestial bodies can be realistically illustrated.

In principle, it is possible to mount the plane purely mechanically in the ball cavity so that it automatically aligns itself horizontally due to its own weight, independent of the ball rotation. A preferred embodiment of the invention consists in the ball cavity being half-filled with a liquid, with the liquid level forming the automatically horizontally aligning plane. In addition to being easy to implement, this has

furthermore, it has the advantage that the liquid can be colored so that the orbits of the individual celestial bodies below the horizon are optically distinguished from the orbits above the horizon.

The rise or set of stars at the horizon boundary can be observed particularly well because the liquid has a given transparency.

Alternatively, it is advisable for the liquid to be completely opaque.

A preferred embodiment of the invention consists in that particles are arranged floating on the liquid, which form the closed horizon plane. A dense, smooth surface is preferably produced by different particle sizes.

Another advantageous development of the invention consists in a disk floating on the liquid. This has the advantage that any movement of the liquid is dampened, for example when the globe is moved. The disk can also be printed or provided with a topography.

It can also be advantageous for the disk to be provided with a floating body which essentially takes up half of the spherical cavity. It is sufficient for the floating body to be supported on a liquid film.

The invention is further described below using an embodiment shown in the drawing.

The only illustration shows a schematic perspective view of a celestial globe.

A transparent celestial globe 1 is divided by a liquid level 3 of a liquid 2, the volume of which corresponds to half the hollow sphere volume of the celestial globe 1, into an upper, visible celestial hemisphere 4 and a lower, invisible celestial hemisphere 5. The liquid level 3 forms a "horizon disk". The outer boundary of this is the horizon 6. The connecting line between the north celestial pole 7 and the south celestial pole 8 forms a celestial axis 9, which runs through the common center 10 of globe 1 and liquid level 3. The center 10 corresponds to the location of an observer during a real celestial observation. Furthermore, apparent orbits of two celestial bodies (celestial bodies) 13,14 are depicted on two small circles 11,12 running perpendicular to the celestial axis 9. One celestial body 13 is above the horizon 6, the other celestial body 14 is below it. When the globe 1 rotates around the celestial axis 9, the celestial bodies 13,14 move on small circles 11 and 12 respectively.

For the sake of better clarity, the illustration does not show the celestial equator as a great circle running perpendicular to the celestial axis 9, nor does it show the east and west points, which result from the intersection of the celestial equator with the horizon 6, nor does it show other celestial bodies that are usually shown on a celestial globe.

Claims (8)

Protection claims P 1. Transparent celestial globe, characterized in that a plane which automatically aligns itself horizontally and runs through the center of the sphere (10) is arranged in the sphere cavity. 2. Celestial globe according to claim 1, characterized in that the spherical cavity is half filled with a liquid (2). 3. Celestial globe according to claim 2, characterized in that the liquid (2) is translucent. 4. Celestial globe according to claim 2, characterized in that the liquid (2) is completely opaque. 5. Celestial globe according to one of claims 2 or 3, characterized in that floating particles are arranged on the liquid (2), which form the closed plane. 6. Celestial globe according to claim 5, characterized in that the particles have different sizes. 7. Celestial globe according to one of claims 2 to 6, characterized in that a circular disk floats on the liquid (2), the diameter of which corresponds to the diameter of the spherical cavity. 8. Celestial globe according to claim 7, characterized, that the circular disk is provided with a floating body, the volume of which occupies almost the volume of half the sphere cavity, whereby the sum of the floating body volume and the liquid volume is half
Volume of the spherical cavity.