US240705A - Semicircle for nautical observations - Google Patents

Description

(No Model). A O; M. HELLBERG.

semicircle for Nautical Observations.

No. 240,705. Patented April 26,1881.

WITNESSES: INVENTOR: Q56 W- JZAZ M'W BY *fl ATTORNEYS.

N. PETERS. PHDTD-LITHOGRAFNER. WASHINGTON. D. O,

ITE STATES 1 PATENT OFFICE- cHA'ELEs M. H'ELLB'ERG, OF JERSEY oI'rY, NEW JEEsEY.

SEMICIRCLE FOR NAUTICAL OBSERVATIONS.

SPECIFICATION forming part of Letters Patent No. 240,705, dated April 26, 14881,

Application filed October 15, 1880. (No model.)

To all whom it may concern:

Be it known that I, CHARLES M. HELL- BERG, of Jersey City, in the county of Endson and State of New Jersey, have invented a new and Improved Semioircle for Making Angular Measurements, of which the following is a specification.

The object of this invention is to provide an improved instrument for taking observations at sea, either at day or night, to determine the ships position.

The invention consists of a frame having an arc of one hundred and eighty degrees,suitably and adjustably mounted, in combination with a day and night binocular telescope and reflecting-glasses, said instrument being designed as a substitute for the ordinary sextant or quadrant.

Figure 1 is a perspective View of the device. Fig. 2 is a plan of the same, partly in section, and with parts broken" away to exhibit other parts. Fig. 3 is a sectional side elevation of the same.

Similar letters of reference indicate corresponding parts.

The quadrant and sextant in common use are of but little or no service at night, especially on a dark night, because they are provided with non-magnifying object-glasses and glasses. of small aperture. Hencein high latitudes in winter, when the sun cannot be seen for days, the ordinary sextant is of no value to the navigator.

The improved instrument consists of a suitable hollow case, A, preferably of ellipsoidal cross-section for the sake of strength, provided. with end strengthenin gencirclin g ribs, a a, and having sockets or openings 1) b made through it for the reception and free movement of the semicircular frame B, which consists of an are, c, of one hundred and eighty degrees, graduated in the usual manner with sextants, as shown at c, and having a toothed periphery, as shown at cl, for the engagement of the thumb-wheel G, that is journaled in a hanger, G, which depends from the under side of the case A. The frame B serves the same purpose as the arc in the ordinary sextant or quadrant, being lengthened into an arc of one hundred and eighty degrees for better ad a-ptation to the case A and telescope I. Said semicircular frame B is also provided with radial strengthening-braces ff, that converge to a central point. Fixed on the lower part of the brace f, and extending at right angles from either side thereof, is a reflector, D, that is designed to receive the rays of light from the observed object. mounted or pivoted so as to move in a vertical plane on a horizontal pin, g, that is supported in the lugs h h, which project upward from the top of the case A at the front thereof.

Bi gidl y secured on the top of the case A is a vernier, E, to facilitate the reading of the are c.

A straight forward arm or extension, F, from the bottom of the case A, supports on its outer end a reflector or horizon-glass, G, which is designed to receive the reflection from the reflector D.

Within the front end of the caseAis an annular groove, 1, within which is fitted a colored glass, H, to prevent the rays of light reflected from the horizon-glass reflector G into the binocular telescope I from injuring the eyes of the operator. Said glass His preferably set in place through a slot, 12, made for that purpose in the side of the case A 5 but it may be placed and held in position in any other well-known manner. The telescope I resembles an ordinary opera or field glass of good magnifying powers, and of large apertures for service as a night-glass, and it is set in the case A'so that it can be readily removed and used simply as a' telescope.

In taking an observation with this simi-circle the operator can use both eyes, and thus employ the full strength of his sight, and can Said semicircular frame B is see farther and more clearly than with the ordinary sextant-glass. The horizon can be clearly seen by the operator looking through the telescope I, even behind thehorizon-glass G.

This instrument can be used without night and day glassesin the same manner as the ordinary quadrant. It is intended chiefly for night observations.

The eye-plateK is provided with two minute orifices, m m, and hinged or pivoted, as shown, to the rear end of the case A. Lookingthrough the orifices mm, when the telescope is removed and the eye-plate K is closed, the operator can take a good observation in a clear day.

I do not confine myself to the use of the thumb-wheel O for moving the frame B, as obviously other and well-known devices may be used for this purpose, the wheel 0 being herein shown to indicate a manner of adjusting said frame B.

Having thus fully described my invention,I claim as new and desire to secure by Letters Patent 1. An improved semicircle for making angular measurements, constructed substantially as herein shown and described, consisting of case A, pivoted semicircular graduated frame 13,, Vernier E, reflectors D G, and binocular telescope I, operated as set forth.

2. In a binocular instrument for making angular measurements, the combination, with a pivoted adjustable semicircle,B,provided with a graduated arc, c, of the fixed vernier E, sub stantially as and for the purpose described.

CHARLES M. HELLBERG.

Witnesses:

I. I. STORER, (J. SEDGwIoK.

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