Microscope and telescope Optical refracting Telescoping history Refracting Commentary

Zacharias Janssen, Hans Lippershey, Jacob Metius, Cornelis Drebbel optics

Microscope and telescope

• Zacharias Janssen,
• a street seller often in trouble
• and a counterfeiter of coins,
• or his father, or his son,
• or his neighbor Hans Lippershey,
• a spectacle maker,
• or Lippershey’s assistant—
• one of these people—
• invented the microscope,
• or, on similar principles,
• the telescope, or both.
• Other Dutch spectacle makers
• in Middelburg and Alkmaar
• including Jacob Metius
• and Cornelis Drebbel
• made similar claims.

Optical refracting

• The simple single-lens
• optical refracting microscope
• uses a convex lens.
• The compound
• optical refracting microscope
• uses two convex lenses.
• A magnifying glass
• is simple single-lens
• optical refracting microscope.
• The first optical refracting telescopes
• had a convex objective lens
• and a concave eyepiece lens.
• Kepler’s
• improved telescope
• had two plano-convex lenses.

Telescoping history

• The Dutch telescopes
• magnified distant objects
• three times.
• Galileo Galileli’s
• improved telescope, in 1609,
• magnified eight times.
• In 1610, Galileo
• observed the moons of Jupiter
• with one of his telescopes
• that magnified thirty times
• which he called a perspicillum
• or his occhiale or “eyepiece”
• and which in 1611
• Giovanni Demisiani
• called a telescope.
• In 1609, Galileo made
• a compound microscope
• that he called an occhiolino,
• his “little eye,”
• which in 1625 Giovanni Faber
• called a microscope.
• Isaac Newton in 1668
• built the first reflecting telescope
• using a curved mirror instead of lenses.
• Christiaan Huygens in 1733
• made an achromatically
• corrected microscope.

Refracting

• An eyeball bends light
• to a little retina.
• The lens in the ball
• angles the light.
• A line of refractions
• in the eye
• a series of refinements
• in the mind
• make a small scope
• seem large.