Ever wondered what the first binocular looked like? Well, they barely resembled what you see today.They have come a long way, just like other awesome stuff we have today. As you can imagine, they only got better as time went by and manufacturers had access to better materials and fabrication techniques. In that regard, let us look at the history of the binoculars, along with its cousin, the telescope.
In binoculars, manufacturers use a prism assembly to project an upright image, which would otherwise appear inverted, as it is the case with astronomical telescopes. While the binoculars and refracting telescope may have slight differences in their design, their development happened almost concurrently for a while.
Moreover, there was much more to their advancement than just the advancement of optical designs. Other factors that contributed immensely to their final design included huge leaps in manufacturing technology and fabrication of materials used in their design. A case in point is the precision brass tubing, which the pioneer manufacturers used to design early optic devices in the mid-1700s.
History of Binoculars [The Invention]
Hans Lipperhay was among the first people who are credited for publicly declaring they had invented a device that allowed objects at a distant to be viewed as if they were close by. On September 25, 1608, he received a letter he received an introduction letter that invited him to the States-General at The Hague.
He was supposed to present his invention, and get a patent. However, a week later, he received another letter from the State General that requested him to improve the device’s design so that a user could use it with both eyes. He did it and presented his binoculars on 4 October 1608, where a committee formed to examine the invention tested it on the tower quarters of Excellency.
When they reported on their findings on December 15, 1608, they said the device worked as the Hans Lipperhay claimed. However, they denied him the patent, saying others had made claims of the same invention. Quite a painful moment for him considering no one else had applied for a patent and demonstrated their idea of a binoculars.
Unlike the refracting telescope that had evolved to its modern configuration by the mid-1700s, the binoculars had to wait until 1894 to complete its evolution. The long wait was because of the extra complexity required to display optically transmitted images upright and compacting the mechanism. It was only after the modern prism was included in its design that the revolution was complete.
Features of Modern Binoculars
• Two telescopes,
• Erected images,
• Handheld design,
• Two telescopes with parallel optical axes,
• It has matched magnification.
History of Telescope
Galileo used a long and a high magnification telescope in his astronomical observation. His was the first practical telescope, that also led to advancement in astrology. The first telescope that he produced had a magnification of 3x-10x which he later advanced it to 20-30X. He published his observation about the moon of Jupiter, Milky Way and the constellation. Other observations that he made include the phases of Venus, the ring of Saturn and the sunspot.
This telescope was constructed by Christopher Scheiner in 1617 though it had earlier been proposed by Johannes Kepler in 1611. The telescope had a high magnification, inverted images, good field of view and longer length. In order to produce erect images, he introduced a single erecting lens.
A practical terrestrial telescope that had an erect image was later introduced by Anton Maria Schylrle in 1645 by using two elements erecting couplet. The telescope had an acceptable field of view and magnification. A two lens eyepiece telescope was later introduced that incorporated both eye lens and field lens in 1662 by Christiaan Huygens.
Some of the telescopes had additional field lens at/near the first intermediate image which this resulted to a five-lens eyepiece. Some evidence suggests that the four lens eyepiece was used in the late 1600 but fell out of favor till mid-1700.
That was because of advancement in achromatic objective in the mid-1700s. The modern design of the terrestrial refracting telescope that was available that time, also contributed to their disuse. Telescopes also began to use brass tube with a majority of them produced going for military and nautical purpose.
How Do Binoculars Work?
Different colors of light are bent at a different level as they go through the dispersing prism. The edge of the lens acts as a dispersing prism and as the light goes through it, different colors will be focused at different distances. Smaller objective lens can be used to limit the blur associated with a chromatic aberration in pre-achromatic telescope.
Chromatic aberration was believed to be fundamental and could not be corrected in the early 1700s. But the work of John Dollond and Chester Moor Hall led to the creation of achromatic objective.
Here, two lens having different dispersion properties were combined to form a single objective lens. This made blue and red light to focus on the same location and this minimized the blur even on large diameters.
What is the Function of Prisms in Binoculars
Chester Moor Hall who was the original inventor, commissioned 2 opticians James Mann and Edward Scarlet in 1733 each to make one lens element. Coincidentally both opticians subcontracted the work to George Bass.
At around 1750, George Bass discovered that different glasses had different dispersing power and invented an achromatic lens. He gave this information to Dollond who began a series of experiments using different glass types.
Dollond’s son named Peter saw a commercial advantage and patented the invention once the test lens was made in 1758. Chester Moor Hall challenged the patent twice but lost on grounds that the person profiting from the invention, is the one benefiting the public by it, and not the one who locks it in his desk.
This led Dollond to become the dominant manufacturer in late 1700s and his name became a synonym for the telescope.
Paper was used to make telescope throughout the mid-1700s. It was rolled into tubes with vellum or leather covering which provided some water resistance. Turned wood, horns or ivory was used to make a protective ring on the draw and the lens cells.
A famous one was an Italian paper telescope that was constructed with paper tubes decorated with vellum. It also had a Schyrle erecting system and was 850mm long with the main barrel having a diameter of 55mm.
Precision Brass and Tubing
It was until the end of the 1700s that high-quality brass become available. Although they were first used in the 1750s, and were first put to use in 1740. Preparation of brass for drawing was done by rolling a sheet of metal into cylinder. The cylinder was then wrapped around a mandrel that defines the diameter of the inner tube.
The cylinder abutting edge was silver soldered. The brass cylinder was then drawn by force through a steel die. To produce the desired thickness of the wall, a series of a die was being used.
History of the Binocular
Keplerian telescope and Galilean telescope were the two scopes that evolved into a binoculars in two different ways. The attempt to modifier them started in the 17th century, with both designs experiencing difficulties in focusing, alignment and magnification match. That made reproducible manufacturing almost impossible.
In early 1700s, small Galilean telescope called spyglasses with a magnifying power of 2-3X was common. Advancements were made in the field of view at the late 1700s by using large objective and achromatic objective. In 1823, Opera glasses were invented by J.F. Voigtlander.
He used a frame with two bridges to combine two achromatic spyglasses of opera glasses. Advancements were made by J.P Lemiere in 1825 who was from Paris. He improved this by adding a third bridge between the eye tubes and focusing mechanism. The focus of the early design was by turning the body of one telescope to drive the motion of eye tube.
Optical Improvement of the First Binoculars
It was until late 1800s that the quality of optics improved. Opera glasses was by now available with triplet eye lenses and triplet objective with a large diameter lens. This combination had a wider field of view and minimized chromatic aberration. The magnification here remained at 3X.
Highest magnifying Galilean binocular power was about 5-6X. These field glasses were Majorly used for military applications. It’s in the 1800s that the field glasses started using aluminum immediately it became available.
Field glasses and opera glasses have a simple optical system which is an advantage. However, they have a limited field of view and relatively low magnification inherent to Galileo telescopes.
This is a combination of two Keplerian telescopes with Schyrle erecting lenses. This configuration tended to be long because of a number of optical elements. Early attempts were made to construct this form of binocular in the 1600s, but faced challenges in magnification match, alignment and focusing.
The optical system was complicated because of long length and high magnification. The issues were worse with twin telescope than the Galilean binocular.
Porro Prism System
Attempts were made by Ignacio Porro in 1854 to fabricate prism binocular but failed due to the poor quality of glass. The association of Carl Zeiss with Otto Schott who was a glass maker resulted in the production of the high-quality prism. These prisms were important for Porro prism binocular. Ernst Abbe provided the optical design of the prism and was first sold in 1894.
It was in mid-1800s when Giovanni Amici added the roof surface to the prism which deviated light by 90 degrees. Erecting prism system that incorporated roof surface was introduced to binoculars in 1897 and was first used in pentaprism configuration.
Abbe Koening Erecting Prism
This kind of prism first appeared in the early 1900s, image erection was able to be obtained without optical axis being displaced. While still in use today, this prism is a precursor of the Pechan roof prism in modern roof prism.
It’s possible to build some asymmetric in this prism so as to provide an offset of the optical axis, this will be a great objective lens with a large diameter.
Sprenger Leman prism binocular slide 76
In 1898, Hensoldt introduced a more compact arrangement using leman prism. By 1907, production of binocular incorporating roof prism was done by Zeiss.
The Modern Binocular is Quite Advanced in Design
Handheld telescope and binocular development greatly relied on advancement of engineering and material fabrication techniques. Moreover, the design of a binocular is more complicated than that of the average telescope because of the need to project an upright image.
Modern design form of the terrestrial refracting telescope was achieved in little over a century, while it took nearly 3 centuries for binocular. Critical advances were made in manufacturing technology, mechanical design and optical glass.
The precision brass tube which was available in the mid-1700s played a critical role in optical instrumentation. Overall, the modern binocular has a lot to offer thanks to today’s manufacturing and material available.