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Telescope Timeline

By Aiden Soo
  • 3500 BCE

    Discovery

    Phoenicians cooking on sand discovers glass.
  • 424 BCE

    Making glass spheres

    Aristophanes uses a glass sphere filled with water to start fires. Lenses would not be used to study the stars for 2000 years.
  • 1400

    Farsightedness are developed

    convex lenses to correct farsightedness are developed.
  • 1500

    nearsightedness are developed

    concave lenses to correct nearsightedness are developed.

  • First documented creation of a telescope

    In the Netherlands, Hans Lippershey discovers that holding two lenses up some distance apart bring objects closer. He applies for a patent on his invention. This is the first documented creation of a telescope. The idea is independently developed by Jacub Metius and Sacharias Janssen. The patent to Lippershey is denied

  • irst person to make a drawing of the Moon through a telescope

    -Thomas Harriot (1560 – 1621) English astronomer, mathematician, ethnographer, and translator becomes the first person to make a drawing of the Moon through a telescope, on July 26, 1609, over four months before Galileo.

  • builds several telescopes of his own and turns them toward the heavens.

    Galileo, after simply hearing that the device was invented, builds several telescopes of his own and turns them toward the heavens. He dared to publish his findings and was nearly burned at the stake for it. There are other earlier recorded astronomical uses including viewing stars with Lippershey's own first telescope during its demonstration and Thomas Harriot's views of the moon not long after.

  • Johannes Kepler switches from a concave eyepiece to a convex eyepiece.

    Johannes Kepler switches from a concave eyepiece to a convex eyepiece. This not only allowed a larger field of view, but it allowed for the projection of images (such as the sun) onto a flat white screen. Although the images are inverted, Kepler demonstrates how a third convex lens turns the images right-side-up again. The use of a third lens also degrades the images, so this form of the telescope is not widely used.

  • The term "telescope" is coined by Prince Frederick Sesi

    The term "telescope" is coined by Prince Frederick Sesi at a reception where Galileo is demonstrating his instruments.

  • Rene Descartes

    Rene Descartes demonstrated that speherical lenses cannot produce pinpoints of light. He studies elliptical and hyperboloidal lenses and demonstrates that different combinations of hyperboloidal lenses or elliptical lenses will produce a pinpoint of light and a sharper image.

  • Robert Hooke

    Robert Hooke demonstrates how to shorten the tube by using three or four perfectly flat mirrors to reflect the image back and forth in a shorter tube. A 60-foot long telescope can be reduced to 12 feet long, greatly simplifying support and stability.

  • Johannus Hevelius

    Johannus Hevelius realized that the longer the telescope was, the closer together the different colored points of light would be at the focal point, yielding a sharper image. He constructs a telescope 140 feet long which probably gave very sharp images, but it was almost impossible to keep the two lenses aligned because the supporting structure (usually a long tube) could not be made rigid enough.

  • Christian Huygens

    Christian Huygens suggests getting rid of the supporting structure and mounting the objective lens on the top of a long pole. These were called "aerial telescopes" because they were open to the air. They were also much easier to build and use. At the same time, Huygens developed a compound negative eyepiece using two air-spaced convex lenses. This arrangement cancelled out some of the chromatic aberration that occurred in a single lens eyepiece.

  • Chester Moor Hall

    Chester Moor Hall develops an achromatic lens. Two pieces of glass with different indices of refraction can be combined to produce a lens that tends to focus most colors at a very close (though not exact) point. Red and Green neatly blended at a point, but blue-violet still missed that point by a small amount. The result was a much sharper image with violet halos around brighter objects. Refractors are suddenly popular again.

  • James Short

    The Scottish Instrument maker James Short invents the first parabolic and elliptic, distortionless mirror ideal for reflecting telescopes. Short accomplished this in a very practical manner: Since parallel rays nearer the center of a spherical mirror overshoot the marginal rays coming from the edge of the mirror, why not just deepen the center to bring all the rays of light to the same point of focus? James Short built over 1,360 telescopes. All had speculum mirrors.

  • John Dolland

    John Dolland improves upon the achromatic objective lens by placing a concave flint glass lens between two convex crown glass lenses. This triplet uses the natural differences between the refractive indices of the two types of glass to cancel out chromatic aberration even more. Some historians claim that the triplet was introduced in 1765 by Peter, son of John Dollond. Many excellent telescopes of this kind were made by him.

  • Sir William Herschel

    Sir William Herschel constructs a forty foot long telescope with a four-foot diameter mirror. Reflector telescopes have become popular again because they can be built with enormous mirrors, capable of gathering hundreds or even thousands of times more light than a refractor. Today we call them "light buckets."

  • H. Dennis Taylor

    H. Dennis Taylor, optical manager of T. Cooke & Sons of York, makers of astronomical telescopes, designed and patented the revolutionary, and now famous, triplet design