DE102008010844A1 - Manual direction finder for locating e.g. elliptic plane, has video camera positioned at semicircular edge of ecliptic plane and continuously shooting western sky with ecliptic appearing as line - Google Patents

Abstract

The direction finder has a reference system consisting of a horizontal base plate, a vertical semicircular ring, and a device for finding a direction of a setting sun. A position of an ecliptic plane is derived from an individual vertical plane. A video camera is positioned at a semicircular edge of the ecliptic plane and continuously shoots western sky with an ecliptic appearing as a line. An image is simultaneously showed on an image screen to an individual observer or a large observer circle, so that the observer determines whether crescent is viewable or not.

Description

In the Islamic countries Both lunar and solar calendars are used. The lunar month does not start with the astronomical conjunction of the moon and the sun, but with the Erstsichtung the "new light." He also ends with the sighting of the following crescent moon. The determination of the Islamic holidays and pilgrimages is exclusively based on the lunar calendar Perception of the fine crescent moon with the naked eye. Beginning and end of Fasting Ramadan, for example, after appropriate discovery the crescent moon set. It must be that of any observers witnessed sighting be blessed by the Kadi. Because the crescent moon is very narrow on the first day, often erroneous statements, the one big one Cause confusion and a wrong termination of the holidays can result. Due to the local and time-changing astronomical conditions of visibility of Neulichts abuts the elaboration a uniform lunar calendar to great difficulties. The im Device described below allows the untrained observer the rapid and targeted searches for the new crescent moon in the western sky, and, in the case of non-sighting, the To have certainty that he is watching in the right direction and that the next lunar month has not started yet.

Similarly the observer before sunrise the waning moon in the east to Purpose of assessment and predicting when the next lunar month will begin.

Astronomical foundations

The Moon path lies in a plane, which makes an angle of approx. 5 °, 15 with the Plane of the Earth's orbit (ecliptic) forms. From the observer on the earth seen, the new crescent moon is in a "prism" of about 10 °, 50 opening, with an "upper" and "lower" half of 5 °, 15 on both sides the ecliptic. The crescent moon is only exceptionally in the ecliptic, when the moon at the time of the conjunction of the ecliptic pierces what causes a solar eclipse. The new moon always remains "close" to the ecliptic, so looking for the sickle in the western sky on the Finding the ecliptic plane is traced back in the sky. This forms with the vertical at the time of sunset a certain Angle, which depends on the latitude and the declination of the Sun dependent is.

The Finding the location of the ecliptic at sunset and sunrise is the task of the presented below simple locating device.

The instrument

• 1. Eine kleine Version, die hier ausführlich beschrieben wird; der Beobachter sitzt an einem Tisch, auf dem das Gerät aufgebaut ist und kann sitzend in den Himmel schauen. Diese Version wird als mobil angesehen, da das Instrument leicht zu transportieren ist;
• 2. Eine größere Version, basierend auf dem selben Prinzip; der Beobachter steht und das Gerät, mit größeren Abmessungen, wird aufgebaut ca. 10 m von ihm entfernt. Diese Version wird an einem festen Ort eingerichtet.

The instrument is made in two different sizes:

• 1. A small version, which is described in detail here; the observer sits at a table on which the device is built and can look sitting in the sky. This version is considered mobile because the instrument is easy to carry;
• 2. A larger version based on the same principle; the observer stands and the device, with larger dimensions, is set up about 10 m away from it. This version is set up in a fixed location.

It can also different miniature versions in the form of simple protractors or subjects be built where a line is attached to the ecliptic inclination angle display.

principle

By the earth's rotation changes the location of the ecliptic plane for an observer standing on the ground constantly. To determine the position of the ecliptic, it is sufficient to have two intersecting Determine straight lines that lie in the ecliptic.

at Sunrise and sunset can be "materialized" in a simple way Straight is the direct ray, which is the observer with the sun combines. The second is in the plane, the sunrise or sunset the sunlit hemisphere separates from the "night hemisphere": the terminator level. The second straight line is parallel to the ecliptic plane and forms with the vertical at the point of observation, at the time of sunrise or sunset, a certain angle, that of the date and geographical Width depends. This Angle is for the 21st of each month for geographical Widths between -65 ° and + 65 ° calculated and tabulated.

Of the Observers need only point to the point where the sun rises or falls goes down and the imaginary Scouring line in the sky with the sun going through Vertical plane forms the calculated angle. The angle is for the northern hemisphere to the south directed and vice versa for the southern hemisphere.

description

• 1. einem einstellbaren Stativ von ca. 40 cm Höhe mit eine Fußplatte aus Aluminium. Es ist versehen mit einer Wasserwaage und drei Einstellschrauben;
• 2. einer halbkreisförmige Grundplatte aus Plexiglas (Durchmesser: 50 cm), die auf dem Stativ durch ein Verbindungsstück aufgebaut und mit Hilfe der Wasserwaage und der Einstellschrauben in die Horizontale gebracht werden kann;
• 3. ein Halbkreisring aus Plexiglas (Durchmesser 50 cm), der senkrecht auf der Plexiglasgrundplatte als Vertikalebene auf dem geraden Rand aufgebaut wird, und mit eine Winkeleinteilung von 0° (Vertikale) bis 90° (Horizontale) versehen wird, die die Neigung der Ekliptikebene gegen die Vertikale anzeigt;

The instrument of the first version consists of three main parts:

• 1. an adjustable tripod of about 40 cm height with a foot plate made of aluminum. It is equipped with a spirit level and three adjusting screws;
• 2. a semicircular Plexiglas base plate (diameter: 50 cm), which can be mounted on the stand by means of a connecting piece and brought to the horizontal by means of the spirit level and adjusting screws;
• 3. a semicircular ring of Plexiglas (diameter 50 cm), which is perpendicular to the Plexiglas base plate as a vertical plane on the straight edge, and with an angle of 0 ° (vertical) to 90 ° (horizontal) is provided, the inclination of the ecliptic plane indicating against the vertical;

The Parts can be assembled and disassembled without effort. Besides, they can be transported in a light padded suitcase.

It can also different miniature versions in the form of simple protractors or subjects be built where a line is attached to the ecliptic inclination angle display.

observation

Of the Observer puts the mobile device on a table and sitting in a chair. He is aiming from the middle of the semicircular edge the sun rising or setting and screwing the base plate, directed to the point where the sun rises or goes down.

The "materialization" of the ecliptic plane An elastic thread is used between the observation point (Eye) and the point at the opposite lying straight edge, on the western horizon, where the sun goes down (or at the eastern Horizon, at the rising sun), stretched over the semicircular ring so that the plane formed by the thread represents the ecliptic plane. This level forms with the vertical at the time of sunset a certain angle. The elastic thread is over the Semicircular ring stretched in the place where the angular division of Inclination of the ecliptic corresponds. The observer only needs his Look in the direction of the imaginary Line of intersection of the ecliptic with the western sky. The crescent is in the range of 5 °, 15 above or below the ecliptic to search.

One Compass is attached to the straight edge of the Plexiglas base plate. The azimuth of the rising or setting sun can be read directly become.

A Video camera can be used at the semicircular edge of the base plate, instead of the Observer eyes, to be attached and to the western sky the line appearing ecliptic constantly film and the pictures project onto a screen. The observer can sit like this look at the canvas and see if the crescent moon is visible is or not.

comment

By changed the earth's rotation The so-defined position of the ecliptic constantly changes with time in particular in the approximately 45 minute time interval, the day after Emerge of the crescent moon separates the setting of the sun from that of the moon. Because the period of twilight is limited, the effect of the earth's rotation can be neglected in a first approximation. In a further step, a similar instrument is made, that takes this influence into account wearing.

Claims (1)

Manual direction finder for the rapid detection of the ecliptic plane and the new crescent moon after the conjunction, at the moment of sunset or thereafter, on the western horizon, with the naked eye, without astronomical instrument - automatically and with preprogrammed tracking - and for any location. It is characterized in that: - the reference system consists of a horizontal base plate with a device for finding the setting sun and a vertical graduated semicircular ring in the plane of the terminator. The position of the ecliptic plane is derived from the particulate vertical plane in which Zenith and the setting sun are located; - the setting of the ecliptic plane's zenith distance, which depends on the sun's date, time and latitude, at the time of sunset is done manually with the aid of tables (for time points after sunset, direction of azimuth and altitude / depth and zenith distances are also calculated using tables adjusted manually). The ecliptic plane is materialized with an elastic thread fastened at both ends of the direction finder and stretched over the annulus (terminator plane) corresponding to the zenith distance. The crescent moon lies in a range of +/- 5 °, 15 from the ecliptic and, after two days, up to about 24 ° from the sun; - With an additionally built, directed into the ecliptic video camera (optical axis in the direction of bearing), the observation is continuously recorded. The picture is shown to the single observer or a larger observer circle simultaneously on a screen.