SU67877A1 - Instrument for determining the direction of the astronomical meridian - Google Patents

Description

In the production of topographic surveys, it is necessary to determine the direction of the astronomical meridian to determine the magnitude of the magnetic declination. The known methods for determining the direction of the astronomical meridian can be divided into three groups.

1. Very accurate ways that require the use of a theodolite and a chronometer, as well as knowledge of astronomy. These methods are time consuming and are associated with the production of calculations. A major step forward is the Krasovsky Vinogradov method, which allows one to determine declination by a theodolite without a chronometer and without calculations using special tables.

2. Sufficiently accurate methods that require neither a theodolite, nor a chronometer, nor special knowledge of astronomy. Such methods include determining the direction of the astronomical meridian by the sun by the gnomon, as well as by the plumb line during the upper climax of the Polar Star. Topographers usually use the gnomon. But this method takes almost a whole working day, and sometimes 2-3 days, if the sun turned out to be closed after midday on the first day of observation, and the next day became overcast. The use of a plumb line at the time of the upper climax of the Polar Star during the summer months is not possible, therefore, this method is not applicable at the time when the greatest number of topographic surveys are made.

3. The methods are very fast and do not require any tools or special knowledge. Such methods include the method of prof. N. D. Pavlov, but it is extremely inaccurate. During their research, geologists and scouts conduct eye surveys, work with compass or rock compass with diopters, and magnitude of magnetic declination is taken either from the map or from a map or by requesting a geophysical observatory. In this case, it is assumed that the magnitude of the magnetic declination remains constant throughout the entire area of the survey, although in very many cases this is completely not true.

Topographers, working in areas where a triangulation network is already broken up or where there are astronomical points, easily and quickly set a menzula, using the azimuths of certain objects.

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But if a topographer has to make surveys where there is neither a triangulation network, nor astronomical points, and such cases are quite frequent, especially when photographing the rich areas, then establishing the direction of a true astronomical meridian without a theodolite turns into a difficult task.

According to the present invention, for determining the astronomical meridian, a device is proposed that enables geologists and topographers to determine magnetic declination without an expensive theodolite, without a chronometer, without calculations and without having special knowledge of astronomy.

Determining the direction of the astronomical meridian by the proposed instrument is made by observing the Polar and auxiliary stars (J.-B. Medveditsa or i; -Cassiopeia) and introducing the latter and the latitude of the observation site by adjusting the polar azimuth value. According to the invention, the device is made in the form of a horizontal board, rotatable around a vertical axis and equipped with a horizontal diopter and two inclined diopters suspended from the board and stabilized by a thumbnail. Diopters are designed to set the vertical polar and fix the direction of the astronomical meridian. To determine the polar azimuth at the moment of observation, the board is provided with a vertical circle, which serves to read the position of the ruler, which rotates in a vertical plane, perpendicular to the polar plane of the sight and is aligned with the observation line passing through the polar and auxiliary stars.

According to the second constructive version of the device, a tablet was used for determining the astronomical meridian as a board carrying a dioptre, and for determining the polar azimuth at the time of observation a cyctg (90-5) sin (90-f /) - cos (a-aO cos (QO-oQ

ctg x

regel, located in a plane perpendicular to the polarization polarization plane.

FIG. 1 illustrates a method for determining the direction of an astronomical meridian by the proposed instrument, FIG. 2 shows a general view of the proposed device, FIG. 3 modified design of the device.

If two free-hanging threads, for example, two plumb lines, are aligned with the direction to the Polar Star, then the vertical plane formed by these threads gives the Polar vertical at the time of observation. By applying a compass to this plane, the magnitude of the magnetic declination is counted along its northern end, which should be corrected by the polar azimuth value in the following way.

The magnitude of the polar azimuth can be calculated; in the manner indicated in FIG. 1, where Z is the zenith, M is the polar star, P is the pole of the world, F, if cf is the geographical latitude of the place of observation, F, and a is B. Ursa Major; ZPN - the astronomical meridian; ZMS - polar vertical; WNE horizon; angle PZM - polar azimuth; ZMP angle - Polar polar parallactic angle.

Suppose that the parallactic angle of the polar () HaiM is known. Then the azimuth of the polar is calculated by the known formula:

. sin and sin C, ..

sin, (1)

sin with

which in this case takes the form:

sln k sin px

(2)

sin (90 - to) where the p-polar polar distance or arc of the PM.

Then the angle can be calculated by the formula:

ctg a sin C - cos B cos c

(3)

ctg 5

which in this case takes the form: sin (a-a.)

Here, a and a are the values of direct ascents, the magnitudes of the declinations of the Polar Star, and -B. Bears. Parallactic angle Polar / С ZM / - X. You can determine the angle K by measuring the angle ZMF.

If the ZMF angle is projected on a vertical plane, perpendicular to the vertical plane of the polar star, then this angle can practically be measured.

The measurement of this angle can be made using the plumb of a mountain compass. To do this, holding the mountain compass in outstretched hands, position it vertically and plumb to itself so that the plumb bob and then tilt the compass around its axis and align its long torus with the line mentally drawn from Polar to AB. Bears.

Thus, the measurement of the angle of inclination to the horizon of the line connecting Polar with AB. The dipper (auxiliary line) can give the polar azimuth value at the time of observation. To compile a table from which the azimuth of the polar can be determined at any time, it is necessary to proceed somewhat differently. Since the Polar performs a full circle during the day, the angle K varies from 0 ° to 360. We divide this circle into 120 parts with intervals of 3 °. For each of these positions, the value of the angle K will be successively equal to: 0 °, 3 °, 6 °, 9 °, ... 180 °,. . . 270 °,. . . 360 °. Each of these provisions will correspond to its polar azimuth, which is easy to calculate, depending on the formula (2), the corresponding angle values / C. For the given width, you can make a table in which the polar vertical azimuths will be located in the first vertical column, and the corresponding parallax angles of the polar polar column in the second vertical column. Then, in the second column of the table, to each value of the parallax angle, X must be added, after which these corrected angles must be recalculated in their projection onto the vertical plane. This table is subject to simplification, which is based on the fact that the polar azimuths during the day are repeated four times and the same for all Polar positions with parallax angles: from 90 to 180 ° from 180 ° to 270 °, from 270 ° to 360 ° and from 90 ° to 360 °. At the same time, the slope of the auxiliary line FM (Fig. 1), which varies from 0 ° to 360 °, can be measured in quadrants with greater convenience, i.e. from 0 ° to 90 °.

The result is a very simple table, in which the angle of inclination of the line connecting the two stars mentioned above, you can immediately get the azimuth of Polar. When using such a table, it is only necessary to consider which way, i.e., to the west or east, the line connecting both stars is tilted.

Since the early spring and winter B. Bears high in the evening, it is technically impossible to use it. For these seasons it is necessary to use another auxiliary star, for which the p-Kasoiopeia is the most convenient.

These tables make it possible to determine the azimuth of the Polar star without a chronometer at any hour of any day of the year at all eights for which they are calculated if the Polar is visible, and B-Dipper or 8-Cassiopeia.

The instrument for determining the direction of the astronomical meridian (Fig. 2) is made in the form of a horizontal board (rotatable on the vertical axis and tightly fixed) in the center of the circle, which is screwed onto an ordinary wooden photographic stand 2 that does not have iron screws. On board 1, two oblique diopters 3 and 4 are sublime, which are connected below by joint 5. Both diopters swing freely and are in a vertical plane, since at the top they rest on two tips 6 that enter freely into the slots, and at the bottom are drawn 7, having two swing centers. In front di407

Optre 3, slots 8 are at different heights; looking up at them through the horizontal diopter 9 in the board} you can observe the Polar star. The combination of this vertical plane with the Polar Star is first performed roughly, by hand-rotation of the board / instrument. After a rough pickup, the board is fixed with the arresting device 11, and then an accurate targeting of the Polar Star is made with a micrometric screw} 2. After that, slightly loosening the screw J3, tilt the ruler J4 and align it with the line passing through Polar and a-B. Bears. After fixing the screw 13, the angle of inclination of the ruler to the horizon along the vertical limb} / 5 is counted.

In the table on the page that corresponds to the latitude of the observation point, find the value of the angle of inclination of the ruler M, and on this angle the azimuth is Polar. Then, by rotating the micrometric screw 12, the board 1 is rotated by an angle equal to the Polar azimuth, this setting is made with an accuracy of 1. After that, the vertical plane passing through the diopters 3 n 4 is aligned with the astronomical meridian plane, and one can be done of the following operations.

1. Looking through the slit in the upper part of the main dioptra 3 and through the second diopter 4, placed at a significant distance from the device milestone, which together with the observation point gives the position of the astronomical meridian on the ground.

2. By freeing the arresting 17 of the compass of the compass 16 and letting the magnetic needle calm down, read the indication of its northern end and obtain the value of the magnetic declination.

It goes without saying that the board / instrument should be horizontal. To do this, there are two levels 10 on the board, and the board is aligned by hand by rearranging or shortening the legs of the tripod.

In order to give the whole device greater stability, to the head of the clamping screw of the strut 408

is placed on the hook of a small bag filled with sand or stones.

A vertical plane pointing to the polar plane can be done with an accuracy of 7. The polar azimuth value is determined in any case with an accuracy of /. The combination of the vertical plane with the astronomical meridian is made with an accuracy of /. The reference point of the compass has an accuracy of no more than 10. Summing up all the errors, we get 20 if all the errors have the same sign. The average of several observations will significantly increase the accuracy of observations, especially since the above errors will not necessarily have one sign.

The device described above can be modified and simplified, if we bear in mind the topographer, working with a face-piece.

The metal frame is screwed to the tablet, namely, to its eastern or western edge, tightly folded metal, the strip (Fig. 3). In the northern half of this bar, a slit is made with the thread taut in it to obtain a horizontal diopter (not shown in the figure). In addition, conic grooves are made at the ends of the strip from above, into which the tips of both inclined instrument diopters are inserted. In this way, a vertical plane is obtained, which, when observed, is aligned with the vertical plane of the polar. The angle of inclination of the auxiliary line to determine the azimuth of the polar at the time of observation is measured with the aid of a kipregel 2 (Fig. 3). For this, the co-fender is positioned in the direction west-east and the angle of inclination of the auxiliary line is measured, aligning the upper edge of the pipe of the co-fender with this line. The angle of inclination is counted on the vertical limb 4 of the kipregel.

The rotation of the planchet / frame scale at an angle equal to the polar azimuth, i.e. the installation along the true meridian, is carried out in a double way.

If the micrometer screw of the binder has a drum with calibrated divisions, then the rotation is performed by rotating the screw to count its divisions. If it does not have a division drum, then to the north of the scale, at a distance of about 5 m, a small (30-40 cm length) horizontal rail is set, through which tablet 1 is rotated by a certain angle, measured by division reiki.

Since the vertical limb “pregel” closes a significant part of the pipe and therefore will interfere with the observation of stars, it is necessary to put a small metal ruler 5 15-20 cm long on the pipe 3 of the kipregel. This ruler has two supports 6 with half-ring springs at the ends, clamps which are put on the pipe 3 kipregel. Line 5, which is located, therefore, above the kipregel pipe, must be installed parallel to its optical axis. When determining the angle of inclination of the auxiliary line, the upper edge of the ruler is aligned with the observed stars.

One can be completely free from inclined diopters and from a bar with a horizontal diopter if one sees the Polar straight into the pipe of a kipregel, provided that the line of the kipregel is combined with the true meridian drawn on the brillon. However, when working not only at high, but also at mid-latitudes, it is technically impossible to observe Polar in a kipregel, even if there is a reversing prism in its eye.

In order to circumvent this obstacle, it is necessary to apply a kipregel equipped with a long-focus eye-window with a flip-up prism. The focal distance of this ocular is determined by the distance by which the observer’s zygomatic bone of the observer’s body must be moved away from the kipregel tube so that the star can be observed at a very close position of the ocular bipregel tube to its ruler.

Subject invention

Claims (6)

1. Instrument for determining the direction of the astronomical meridian observing the Polar and auxiliary stars (a-B. Medvedits or r-Cassiopeia) and introducing in position the last and latitude of the place of observation a correction for the magnitude of the azimuth (Polar), characterized in that it is made in the form of a horizontal board 1, rotatable around a vertical the axis and the horizontal diopter 9 and two horizontal / angled diopters 3 and 4 suspended by the core 7 mounted to the board and mounted for the vertical direction of the astronomical meridian; 2. The form of the instrument according to claim 1, characterized in that for determining the azimuth of the polar at the time of observation, the board / is provided with a vertical circle 15 for counting the position of the ruler 14 rotatable in a vertical plane, perpendicular to the polar plane of the polar and aligned at observations with the line passing through the polar and auxiliary star. 3. The form of the device according to claim 1, characterized in that the tablet is used as a board carrying diopters 5, 4 and 9 (Fig. 2). 4. The form of the device according to p. 1-3, characterized with the use of a cypregel to determine the polar polar azimuth at the time of observation, located in a plane perpendicular to the polar plane of sight. 5. The form of the device according to p. 3, 4, characterized in that the bobbin is equipped with a ruler mounted on its pipe, which is parallel to the optical axis of the pipe and is aligned when observed with its upper edge with the direction connecting the polar with auxiliary star. 6. In the device according to claims 1, 3–5, use a kipregel with a long-focus eyepiece and a inverting prism to observe the polar directly into the pipe of the kipregel. 409