US940166A - Separating-prism telemeter. - Google Patents

Description

A. KO'NIG.

SEPARATING PRISM TELEMETER.

APPLICATION FILED APR.28, 1908.

940, 166. Patented Nov. 16,1909.

2 SHEETS-SHEET 1.

A. KUNIG. SEPARATING PRISM TELEMETER. APPLICATION FILED APR.28, 1908.

940,166. Patented Nov. 16, 1909.

2 SHEETS-SHEET 2.

UNITED srnrns PATENT OFFICE. I

ALBERT KGNIG, OF J ENA, GERMANY, ASSIGNOR TO THE FIRM 0F CARL ZEISS, OF JENA,

' GERMANY.

SEPARATING-PRISM TELEMETER.

Specification of Letters Patent. Patentd Nov. 16, 1909.

Application filed April 28, 1908. Serial No. 429,613.

To all whom it may concern:

Be it known that I, ALBERT KoNIG, a citizen of the German Empire, and residing at (larl-Zeiss strasse, Jena, in the Grand Duchy of Saxe-Weime'r, Germany, have invented a new and useful Separating-Prism Telemeter, of which the following is a specification.

The invention relates to telemeters having two objectives, a common ocular and a separating prism system. Two such kinds of separating prism telemeters are known: the coincidence telemeter in the narrower sense of the word and the symmetry telemeter according to our application for patent, filed June 23, 1906, Serial No. 323,164. The invention extends to both the said kinds, but only where the instrument has a horizontal base line and the entrance pupils elevated so as to enable observations being made and measurements taken over some obstacle sheltering the observer.

The invention consists in a general arrangement for such telemeters, which is very simple and retains the approved arrangement of the ordinary instrument, having non-elevated entrance pupils, for those parts, upon the position of which the accuracy of the measurement depends.

A coincidtence telemeter with separating prism system and elevated entrance prisms has been already touched upon in the patent specification 661968 (page 2, column 1, lines 50 to 54) in connection with the detailed explanation of a telemeter, whose base line is also horizontal and whose single objective has a vertical direction 'of axis and lies be: low the level of the entrance prisms. With reference to the arrangement of the coin- 1 cidence telemeter with elevated entrance prisms incidentally mentioned, there is nothing set forth except that the separating prismsystem serves at the same time for reerecting the image s (page 2, column 1,

lines 37 to 89). The simple solution of the same problem is according to the present invention. based upon a lens inverting system erecting the images projected'by the objectives. 'By such a system an astronomical telescope is in general elongated by a length equal to four times the focal length of the system. If in the present instrument this length, which extends from the image plane of the objectives to that of the ocular, be.'given a downward direction for the whole or a greater part of the way, it supplies in itselfin suitably choosing the focal length of the inverting lens systemthe required difference in level between the exit pupil and the entrance pupils. From that it follows, however, that all those optical parts, which have influence upon the relative position of the images produced by the objectives, that is to say, in all cases the objective prisms and theseparating prism system as well as the objectives, preserve the same identical level and can be assembled in a rigid tube system as in the ordinary instrument with non-elevated entrance pupils. But the position of the separating prism system can deviate so far from the ordinary one as to permit'uniting of the optical axes by this system also in a vertical plane. The united axis need then only be deflected once again by reflection, to make it horizontal and available as the ocular axis.

In the annexed drawing: Figure 1 is a perspective diagram of a coincidence telem eter constructed according to the invention. Fig. 2 is. a similar diagramof another coincidence telemeter. Fig. 3 is a diagram of a symmetry telemeter. Fig. 4 is a diagram of anothersymmetry telemeter. Fig. 5 is a longitudinal vertical section through a coincidence telemeter, in which the optical arrangement shown in Fig! 2 is made use of.

In the example Fig. 1 two optical square prisms a are arranged in front of the objectives b. The separating prism composed of two prisms c and d cemented together defleets the two optical axes in their horizontal plane and combines them in the common focus of the objectives which lies in the upper margin of the silver film (indicated by cross-hatching) serving as the separating surface. In this arrangement of the separating surface the under half of the inverted image projected from the right objective is combined, in the plane through the focal point at right angles to the combined axis, with the upper half of the inverted image projected by the left objective into an inverted total image. In measuring, the under partial image is moved in a horizontal direction, for which purpose a refractin' prism e movable along the axis is providecI. The combined axis emerging from the separating prism is deflected downward by a reflecting prism f and passes then through the inverting lens g. The reflecting prism it provided with a ridge gives it finally the horizontal emerging direction, in which a Ramsden ocular consisting of the field lens 2' and the eye lens is is arranged. The sum total of all reflections through the prisms of hinder image field, which may coincide with the hinder surface of the prism h, the movable partial image originating from the right objective lies above.

The separating prism system Z m of the second coincidence telemeter, Fig. 2, consummates the combination of the optical axes in a vertical plane. The common focal point, being also the combination point of the axes, lies in the lower edge of the separating surface, and' this edge lies in the exit surface of the separating prism. The prism m is provided with a rid e, so that the two partial images correspond to one another in respect of right and left. The prism n in front of the ocular differs from the prism h in Fig. 1 not only by lacking a ridge, but

also by its position, by virtue of which the emerging section of the optical axis remains in the vertical plane of the former sections. The observer sees in the upper half of the field of. view the movable partial image coming from the right objectlve.

The symmetry telemeter Fig. 3 is provided with a separating prism 0 p, whioh combines the axes in the horizontal plane, the combined axis, however, being immediately de flected downward by a reflecting surface on the prism p, which-corresponds to the reflecting surface of the prism f in Fig. l. A simple reflecting prism 9 gives the axis then the horizontal direction of emergence. In thev field of view of the observer the two partial images abut on one another in a Witnesses:

movable image .is affected with the horizontal inversion. J

As in the construction Fig. 5 the optical parts according to Fig. 2 are employed, this figure needs nofurther explanation.

. The separating prisms shown and described belong to the same class. Separating prisms of any class may besubstituted for them. Also instead of the inverting lens consisting of three-parts cemented together a more composite inverting lens system may be employed.

I claim:

1. A horizontal separating prism telemeter with elevated entrance pupils, comprisin two objectives reflecting p'risms .for suitably deflecting the optical axes individually, a separating prism system, an ocular, an inverting lens system arranged with vertical axis between the separating prism system and the occular, and means for moving one of the image's projected by the objectives.

1 2. A horizontal separating prism telemeter with elevated entrance pupils, comprisring two objectives, two optical square prisms, a separating prlsm system adapted to combine, in a vertical plane, the two optical axes vproceeding from the objectives and the optical square prisms, an inverting lens system placed on the combined optical axis, a. reflecting prism adapted to deflect the combined axis intoa direction parallel to the base line, an ocular and means for moving one of the images projected by the obj ectives. u

ALBERT KONIG.

. PAUL KRr'ioER, Farrz SANDER.

Images