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5 Fqmrx Vunited STATES PATENT OFFICE R. HUNTINGTON. :SPHERICAL TRIANGLE CALCULATOR. APPLICATION FILED DEC.2I, 1918. 1,538,730. I Patented May 4, 1920. ? Z 5 fqmrx vUNITED STATES PATENT OFFICE. ROBERT HUNTINGTON, OF ROSEIBANK, NEW YORK. SPHERICAL TRIANGLE CALCULATOR. 1,338,730. Speci?cation of Letters Patent. Patented May 4, 1920. Application ?led December 21, 1918, Serial No. 267,745. To all whom it may concern . In the separate views, the same part is . Be it known that I, ROBERT HUNTINGTON, designated by the same reference character. a citizen of the United States, and a resident Referring to the drawing in detail, 1 is an of Rosebank, Staten Island, in the county of axis which represents the axis of the earth. Richmond and State of New York, have in A nut 2 is ?xed to the axis 1, and an arm 3 60 vented certain new and useful Improve is ?xed rigidly to the nut 1 by soldering, ments in Spherical Triangle Calculators, of welding, or other suitable process or means. which the following is a description. The arm 3 extends at right angles to the My invention relates to a device of the axis 1, and is connected rigidly at its outer class of mechanical calculators and has as its ends with an equatorial or hour angle circle 65 principal~ object the provision of means 4, which is thus in a plane at right angles whereby the solutions of all problems of the to said axis, arm 3 being substantially a character occurring in spherical calculations, diameter of the circle 4. Mounted on axis 1 ' including its application to nautical astron is a latitude circle 5. The plane of the cir 15 omy, may be obtained with a minimum of cle 5 is at right angles to that of circle 4, 70 computation. l and also is held parallel to the diameter 3. Asecond object of my invention is the Slidably mounted on the latitude circle 5 is production of a device which, when the a meridian circle 6. lThe circle 6 has two given ship’s latitude, declination of heavenly verniers, such as 7, thereon ~"180 degrees 20 body to be observed, and hour angle have apart, which cooperate with a scale on the 75 been set on the device, will enable the opera latitude circle 5 and in the line of the zeros tor to read the ‘zenith distance of the said of said verniers are two pivots, such as 7*‘, heavenly body and true azimuth thereof. on which are mounted a circle 8 which is It will be seen that the said quantities to be the zenith distance circle. One of the points 25 obtained-by the use of my device are those 7“ is assumed as the ship’s position in using 80 required by the vMarcque Saint Hilaire my calculator in the solution of problems. modi?cation of the Sumner method of ?nd it is unnecessary, however, that circle 8 ex ing the ship’s position. tend through the full 360 degrees of arc, A further object of my invention is to and it is made to extend only from one pivot provide mechanical means whereby the equa to the other through 180 degrees of arc. 85 tion for the altitude of a given body may be Pivotally mounted on the axis 1 is a declina solved without computation. tion circle 9, also made to extend through Another object of my invention is to pro 180 degrees of arc. vide means whereby the amount of computa The details of the connection between axis 35 tion necessary in ?nding the ship’s position 1 and circles 5 and 9 are shown in detail in 90 by the Marcque Saint Hilaire method may Fig. 3, in which it appears that pins, such be reduced to a minimum. as‘ 29, are passed through the circles 5 and Further objects will be apparent to those 9 into the endsof the axis 1, thus forming skilled in astronomy ‘or navigation from a 40 pivots-for the circle 9. It is, of course, un study of the. following description and desirable that circle 5 should turn on axis 1 95 claims. with respect to the circle 4, and this is ‘pre In said drawing accompanying and form vented by the arm 3, the circle 4 lying out ing part of this application, I have illus side of circles‘5 and 6, as shown in Fig. 1. trated the preferred embodiment of my in 45 The zenith distance circle 8 is mounted so vention. 1 that it moves on a spherical surface imme 100 In said drawing, diately inside the equatorial circle 4, while Figure 1 is a perspective view of a device the‘ declination circle 9 moves on a spherical embodying my invention; ' surface‘ immediately inside of the latitude F 'ig. 2 is a detail view illustrating more circle 5. There is a Vernier carried by the 50 fully several of the verniers and pivots of declination circle 9 and this cooperates with 105 the device shown in Fig. 1; aiscale on the equatorial circle 4 to indicate Fig. 3 is a detail view partly in section, the angular distance between the plane of on the line 3—3 of Fig.‘ 1 and illustrating the meridian circle 6, and the declination further details of construction of the device circle 9. Also there are two connected ver 56 shown in Fig. 1. niers 11 and 12 sliding one on each of the 110 1,338,730 declination and zenith circles respectively, circle 5, giving the corresponding hour an 65 these two circles being graduated in degrees gle on equatorial circle 4. - of arc to cotiperate with said verniers. Ver It will be understood that circles 4, 5, 8 nier 11 indicates the angular distance along and 9 v~are all graduated throughout, al- - - j the declination circles between the equato though only a small section of each of these rial circle 4 and the point of intersection of scales is shown in the drawing. 70 the declination circle 9 and the zenith dis As an illustration of the class of problems tance circle 8. The vernier 12 indicates the which may be solved by the use of my in angular distance measured on the zenith dis vention, I will now describe the method of 10 tance circle between the pivot of the zenith operation infsolving three problems which distance circle 8 and the intersection of the fre uently come up in navigation: ' 75 plane of the zenith distance circle 8 and the iven ship’s latltude (usually found by declination circle 9. The equatorial circle dead reckoning) , hour angle of sun or other 4 is graduated from 0 to 180 degrees, the heavenly body, and declination thereof, to 15 zero being in a line in or parallel to the ?nd zenith distance, true azimuth and cal - plane of ship’s meridian circle 6. Latitude culated altitude as required in Marcque 80 circle 5 and declination circle 9 are grad Saint Hilaire’s method. Set ship’s latitude uated from zero at the plane of the equa to latitude on circle 5 by shifting vernier 7 torial circle 4 to 90 degrees at the poles to proper point on’ 5; set calculated hour 20 or a line through axis 1. Zenith distance angle on circle 4 by vernier 18, set declina circle 8 is aduated from zero at the pivots tion on circle 9 by vernier 11. The zenith 85 7IL on vernlers 7 to 90 degrees at the center. distance ma now be read on circle 8 by ver The details of construction of verniers 11 nier 12. e altitude is the complement and 12 are illustrated in detail in Fig. 2, in of the zenith distance. The azimuth is read .25 which 13 is a spacing block intermediate the on one of the roses 15. The difference be two verniers and 14 is a pin shown in dotted tween the calculated altitude as obtained 90 lines only passing through the vernier and above and that obtained by observation of the block. The verniers 11 and 12 are con the sun, star or other heavenly body, is the nectedjby the pin 14, but can swivel there error in the position of the ship as assumed '30 on. Consequently, the verniers can accom in the direction‘ of the plane including the modate themselves to an possible position ship and the body, and should be set oil on 95 of the zenith distance an declination circles the chart either toward or from the body and do not hinder the movements of these observed. ' - q ' ' circles. ' To calculate the great circle course and 85 ' In order to indicate the true azimuth of a distance, set one vernier 7 carrying a com celestial body, I provide compass roses pass rose to the latitude of the point of de 100 ’ 15—15 whose centers lie in the prolonga parture on circle 5; set the difference in the tion of the axis of the zenith distance circle. longitude between the points of‘departure 'As shown in Fig. 1, roses 15 are mounted on and destination on circle 4 by vernier 18; 40 blocks, such as 16, carried on ship’s merid move vernier 11 on circle 9 to latitude ‘of - ian circle 6, so that zenith distance circle 8 destination. The distance is then read in 105 may swin freely beneath said roses. It angular units 'on the circle 8 by vernier 12, will be obvious that‘ the azimuth of a body and the true initial Great Circle Course is in the plane of circle 8 can be read directly read on the compass rose.
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