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How Is a Plossl Eyepiece Made?

Austrian G.S. Plossl developed the Plossl eyepiece in 1860. His design, which includes at least four optical elements, remained essentially obscure and unknown for about 100 years. Today, the Plossl eyepiece is highly regarded among astronomers because of their bright views and exceptional contrast.

Production
- Plossls are expensive to manufacture and cost more than other eyepieces.
  
  Good Plossl eyepieces are expensive to produce. They need high quality optical glass and use precisely matched concave and convex doublet surfaces within the eyepiece. Plossl eyepiece manufacturers use four (sometimes five) glass elements set in two symmetrical pairs. This design makes Plossl eyepieces susceptible to internal reflections, so they also require an internally blackened lens barrel, with thread baffles. Well-designed Plossls also have blackened lens edges. Manufacturers of high quality Plossl eyepieces also use anti-reflection multi-coatings on the optical glass. Plossls that do not included these elements in design are considered inferior.
Manufacturing
- A line of Plossl lenses was introduced in the marketplace in 1980 that were a leader in telescopic eyepiece market. Since then, other companies followed, developing and marketing their own lines of factory-produced Plossl eyepieces.
Lenses
- Telescopes lenses require more than just concave and convex lenses. Lenses used in telescopy are actually achromatic, meaning they are made of two layers of glass.

Astronomy