TESSERACT -- Antique Scientific Instruments -- Astronomy

Lunar / Solar Calendar Disk

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PERPETUAL CALENDAR / LUNAR CALENDAR, English, 19th century, made of brass 1-1/2" (3.7 cm) in diameter. One side has a rotating disk marked "Day of the Month For Ever," with a smiling sunface and a ring of month dates. This reads against a fixed ring of weekdays. The other side has a volvelle marked "Moon¹s Age, Phases, and Southings," with circular scales of twice-12 hours, date of the lunar month, and weekdays. An eccentric circle indicates fullness of the moon. In fine condition, this is an uncommon form of lunar / solar calendar. We note a variant version, undoubtedly by the same maker, marked as a tidal calendar "High Water and Moon¹s Age" (Tesseract Catalogue 38, item 58). (8088) $750.

Innovative Telescope in Silver Plate

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SPLENDID MINIATURE TELESCOPE WITH COMBINABLE EYE LENSES AND SOLAR CAP, English, c. last quarter 18th century, signed "J. Bleuler, London." Constructed with tubes and fittings of Sheffield silver plated copper and brass, this little telescope opens from 2-3/4" to 6" (7 - 15 cm) with three drawtubes. The main tube is finished with black enamel over copper. Giving erect images, the optics are a greenish triplet achromatic objective, two swiveling eyelenses useable singly or in combination, and a slip-on solar filter / dust cap. It is signed on the largest drawtube, and numbered 1, 2, 3 on the smallest. Condition is very fine noting a few scratches to the enamel. It is complete with the original cylindrical wood carrying case bound in red Morocco leather. The innovative maker of this unusual telescope was John Bleuler (1757 - 1829) of Ludgate Hill, apprenticed to Shuttleworth, made free in the Spectaclemakers Company in 1779. (8028) $2200.

Carl Zeiss circa 1930

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OFFICIAL CARL ZEISS PLANETARIUM PHOTOGRAPHS, German, c. 1930, the 14 original silver print photographs measuring 5" x 7" (13 x 18 cm), and variously bearing "Carl Zeiss, Jena" stamps, code number stamps, and/or applied printed descriptions. Depicted are planetaria, equipment, and activities. Most sites are in Germany; there are dramatic views of the powerful modernist architecture of the Weimar Republic applied to planetarium buildings. One unforgettable image shows Mussolini departing the Mailand (Milan) "Ulrico Hoepli" planetarium at its dedication on 20 May 1930. (8038) $1150.

"The Optical Paradox"

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THE DIVIDED TELESCOPE -- AN OPTICAL ILLUSION, probably Austrian, c. late 19th century. Lacquered brass sighting tubes, with plain glass "lenses", are mounted through rectangular wood pillars, on a steel column and cast iron base. An air gap is present between the two ends of the "telescope". An observer sees very clearly through the instrument, even when an opaque obstacle is placed in the air gap! A sliding wood panel reveals the secret -- a sequence of four plane mirrors which direct the light down, across, and back up to the viewer. Overall dimensions are 12-1/2" x 15-1/4" x 2-1/2" (32 x 39 x 6 cm), and condition is fine. George Adams terms this "The Optical Paradox, or Double Perspective." A similar device is illustrated by G. L'E. Turner in Nineteenth Century Scientific Instruments (1983), along with an engraving by Tissandier showing such a telescope in use, the observer looking directly through a massive stone! A simple device, but quite uncommon, this the first example we have seen on the market. (8018) $2700.

Celestial Navigation Slide Rule

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UNUSUAL ASTRONOMICAL SLIDE RULE, German, mid-20th century, signed "Gebr. Wichmann." The 11-3/4" (35 cm) long white plastic rule has slider divided with a full calendar scale, cursor with time scales for German summertime (6pm - 6am) and middle-European wintertime, and main plate with diagonal scales. The reverse has a lookup table (corrected to 1948) with readout against a 30 - 64 degree scale on the cursor. In excellent condition with slight warping, this celestial navigation rule is complete with the original card case and instruction sheet. (8027) $650.

Handheld Reflecting Telescope, in Fishskin Case

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MINIATURE GREGORIAN TELESCOPE, English, c. third quarter 18th century. Measuring 7-1/4" (18 cm) overall, complete with turned brass end cap, the instrument has bright speculum metal mirrors, two-element erecting eyepiece system, and external screw focussing to the secondary mirror. Craftsmanship is excellent, and it gives superb images even in daytime. The telescope is contained in its wonderful original shaped case of wood lined with green velvet and covered in black fishskin. Condition is very fine throughout, noting a bit of rubbing to the original lacquer finish on the brass, and loss of one small semicircular end to the case. The miniature Gregorian telescope is known in very few examples; we have had one by Stedman of London (Tesseract Catalogue 52 Item 7), and one unsigned (Catalogue 40 Item 6). A splendid example. (8013) $4950.

Five Planetary Deities

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SET OF FIVE PLANETARY "VUES D'OPTIQUE," German for the French market, third quarter 18th century, each print trimmed to 17" x 12-1/4" (43 x 31 cm) and mounted in a mat 23" x 18-1/2" (58 x 47 cm) overall. The prints are beautifully engraved, with original hand coloring, and depict each planet as a deity overseeing his attributes, with much complicated iconography in the scenes. Along the top each is labeled in French, reading backwards for viewing correctly in a zograscope (see Tesseract Catalogue 83 Item 29 for an example of this parlor viewer). Along the bottom are labels, reading forwards so one can easily identify and select the print, in four languages (Latin, French, Italian, and German). All these labels are complete, but the engraver's name was lost in trimming away the plain margins for mounting. Present are: -- The Moon -- the "second planet" -- the print numbered 222 -- Mars -- "third" -- 223 - -Mercury -- "fourth" -- 224 -- Jupiter -- "fifth" -- 225 -- Saturn - "seventh" -- 227 Condition is fine, the mats showing some soiling and wear, the prints exceptional in their color and design. With all their planetary and divine symbolism, they are the most interesting vues d'optique we have seen. These prints are the work of Georg Balthasar Probst (1732 - 1801), working in Augsburg, Germany, as artist, engraver, and publisher. He was one of an extended family of printers, productive from the late 17th to the late 18th centuries. His views would have been sold individually and displayed at home or by itinerant performers using viewing boxes. The dramatic perspective of the scenes gave an enhanced three-dimensionality when viewed through the lens. (8054) $3950./the set.

Important American Diamond-Ruled Grating

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		ORIGINAL ROWLAND / BRASHEAR DIFFRACTION GRATING, IN GEARED MOUNTING, American, 1895, signed by hand with a diamond stylus, directly on the speculum surface "Plate prepared at the Astronomical and Physical Instrument Wrks. of Jn. A. Brashear, Allegheny, Pa., USA; AE; Ruled on Rowland's Engine, Johns Hopkins University, Baltimore, Md., USA, 1895; 14438 lines to one inch, 568+ to 1 m/m." This remarkable grating is ruled directly on a 2-1/2" (6 cm) square block of speculum metal, with a polished and ruled area 1-3/8" x 1-7/8". It is mounted vertically in a carrier which is rotatable by circular rack and pinion on a substantial base with three leveling feet, all the mounting made of handsome clear lacquered and blackened brass. A glass cover slide protects the grating, which shows some rubbing to the surface, but which produces very good spectra. Condition is very fine throughout.

Henry Augustus Rowland (1848 - 1901), an extraordinary physicist / engineer, made landmark progress in the design and manufacture of ruled gratings, his ruling engines being the best in the world for several decades. John Alfred Brashear (1840-1920) was a mechanical genius who produced numerous superb telescope objectives, and who excelled at creating extremely accurate surfaces (uniform to 1/5 of a light wave!) on speculum metal plates for Rowland's gratings.

A fine example of an original grating, this one graded "superb" by these master makers. (8057) $2400.

Uncommon Globes from Chicago

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AN AMERICAN GLOBE PAIR, c. 1910, each 10" (25 cm) diameter globe signed "Atlas School Supply Co., Chicago, Manufacturers of Globes." The terrestrial gores are color lithographed and dense with detail, and include isothermal lines, important undersea cables, and wireless communications. The celestial gores are printed in blue, with numerous stars with their astronomical letter and number identifications, and with the traditional constellation figures finely printed in pale bronze. Each globe is mounted in a bent wire semi-meridian, which is inserted into an 11-1/2" (29 cm) tall turned wood base with applied distinctive decor of winged torches (?) and sunflowers (?), gold painted throughout. Condition is good noting some browning to the paper, a couple of small scratches, and some flaking to the gold. Possibly of Masonic provenance, an interesting American globe pair. (7029) $2200.

Four-Eyepiece Telescope by Plossl

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		QUADRUPLE-EYEPIECE THREE-DRAW MONOCULAR, Austrian, early 19th century, signed "Plöfsl in Wien." Opening from 3-1/4" to 8-1/4" (8 - 21 cm) and constructed of silver plated brass and copper, this small telescope is fitted with a cemented doublet achromatic objective, and a wheel of four selectable eye lenses. The tubes are rolled and soldered, not drawn. It offers upright images of high magnification but with a small field of view. Condition is fine noting negligible dents and a tiny edge chip to the lens. There is no handle or mount. The original shaped wood case is lined in purple silk and bound in red Morocco leather. Georg Simon Plössl (1794 - 1868) trained with the Voigtländer optical firm in Vienna, founding his own workshop in 1823. By 1845 he employed no less than 36 workers, and was famous for the quality of his microscopes and telescopes. (8078) $1900.

Prague-Centered Projection with Celestial Volvelle

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THE URANOSCOPE OF PROFESSOR ADOLF MACH, Czech, c. early 20th century, signed "Uranoskop. Astronomicko-zemepisny ukazatel. Sestavil prof. Adolf Mach." Constructed on heavy card, 18-5/8" x 19-3/4" (47 x 50 cm), this unusual planisphere has a rotating volvelle of the heavens printed on starched linen, and a rotating brass index pointer, with readout against an outer hour scale divided every minute. Underneath the volvelle is a fixed map of the earth, printed in colors, utilizing a most remarkable projection centered on Prague. Condition is good with general light soiling and wear, and wrinkling to the linen. (8048) $950.

Miniature Telescope Outfit

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		English, mid-19th century, signed "Davis, Derby." The fine little telescope opens from 3-1/2" to 15" long, with six brass drawtubes. The main tube is bound in whale baleen, with a triplet objective lens and erecting eyepiece system with dust slide. Accessories include lens cover, interchangeable high-power eyepiece with solar filter on slide, and adjustable mount for screwing to post or tree. Condition is very fine, the brass cleaned. The maker was John Davis of Derby, working 1828-1873 according to Clifton. (6020) $950.

"King's Patent" Telescope in Sheffield Silver

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A LUXURY TELESCOPE IN SHEFFIELD SILVER, English, c.1800, signed "Kings Patent, Gilbert & Co., London." Opening from 14-1/4" to 46" (36 -116 cm), the telescope itself has a tapered main tube black-enameled with white floral and geometric decoration, three drawtubes, 2" (52 mm) apparently triplet achromatic objective, erecting eyepiece system, and dust slide. The 18" tall table stand has a tripod base with folding legs (which reverse for stowage), tapered central pillar, swiveling altazimuth mount, and telescope clamp. Construction throughout is of heavy silver over copper. Condition is fine and functional throughout, noting some inevitable chipping to the enamel on the main tube. And just where fine sharp outside edges and corners are exposed, the silver has worn through to show the copper, giving a lovely rich contrast to the instrument. The whole assembly fits in an old possibly original carrying case with brass fittings.

Sheffield plating is a process invented c. 1740, whereby a sheet of silver is fused to a thicker one of copper, and the laminate then rolled to thin it out. A further sophistication was patented in 1782 by J.L. Martin (Benjamin Martin¹s son), a process of drawing silver-plated copper telescope tubes directly by machine. This all became obsolete in the mid-19th century, with the advent of electroplating.

"Gilbert & Co." seems to have been a c. 1800 briefly held business name used by variously interconnected Gilbert family makers of navigational and optical instruments; Clifton records no less than six related Gilbert makers (through their total working range of 1719 to 1845), plus the following partnerships: W. & T. Gilbert; Gilbert and Gilkerson; Gilbert & Son; Gilbert & Sons; Gilbert & Co.; Gilbert & Wright; Gilbert, Wright & Hooke; Gregory, Gilbert & Co.; Gregory, Gilbert & Wright. Both Gabriel Wright and Henry Gregory held royal patents for navigational instruments, but we have not clearly identified this "Kings Patent". The present instrument is a beautiful example of the Gilberts¹ speciality of luxury craftsmanship of telescopes. (8025) $8950.

Demonstration, Experimentation & Calculation