Friday, December 25, 2009

Opera Glasses - High Fashion, Spyware Or Optical Instrument?

By Jeff Bridges

If it wasn't for the Dutch optician Hans Lipperhey, we might not have had either binoculars or opera glasses today. He first started manufacturing simple binoculars in 1608. These were not much more than two telescopes connected by a central bridge, but they led to many further modifications and improvements. His early binoculars had a magnification capability of x3. Within less than a year the Italian mathematician and inventor Galileo Galilee made another drastic stride forward by increasing the magnification ability of telescopes to x30.

Binoculars gave a much wider field of view than telescopes, but since they had 2 convex lenses, the picture that you saw was inverted. It wasn't until 1617 that Anton Schyrle added an additional lens to re-invert the image. In 1758 John Dollond of England invented the achromatic (color free) lens and thereby solved the problem of color distortion.

Another major step forward was the development of prismatic binoculars by an Italian by the name of Ignazio Porro - a gunnery officer. Prismatic binoculars had a much wider field of vision than before and offered dramatically improved magnification abilities as well.

Opera glasses are mentioned for the first time in London newspaper advertisements dating back to 1730. These were not binoculars, but small Galilean telescopes. They were both used decoratively and to watch opera with. The bodies were often inlaid with gems, mother of pearl, ivory, enamel and other types of decorations.

We find references to binocular opera glasses for the first time in Vienna during 23. They were still really not much more than two tiny telescopes connected by a bridge. You had to focus the telescopes individually by expanding the tubes.

These very soon became as much a fashion item as an optical instrument. The designs became more elaborate and had to be worked on by painters, goldsmiths and other artists to create the ultimate fashion accessory. Theater goers not only used this to watch the stage, but also to scrutinize other people in the audience - presumably to see who else had opera glasses!

Within a few years the design was improved to make it possible to simultaneously adjust both lenses. This led to an immediate increase in the popularity of this type of glasses. They also turned into much appreciated gifts - as is apparent when looking at the inscriptions encountered on many opera glasses dating from that period.

Although there are nowadays a multitude of different types of opera glasses on the market, they fall into two categories: monocular and binocular. Within those categories you get all the colors of the rainbow and all the styles and materials you can think of. You even get opera glasses with handles and reading lights. One of the more unusual types is one with a jealousy glass - so you can unobtrusively watch someone else in the audience!

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