Of the many titles conferred on Galileo Galilei, ‘The Father of Modern Observational astronomy’, is perhaps the most apt one in context of today’s topic – Telescopes. We all know that the credit of improvements to the telescope and the consequent astronomical observations goes to Galileo. Although the first telescope appeared in the Netherland, it was this grand master who took the invention to the next level.
Galileo redesigned the instruments with increasingly higher magnifying power. His first basic model was essentially a tube containing two lenses. The three-power instrument was refined to a version that could magnify objects approximately nine times. This video below is a great documentary that walks us through his innovation, its impact and his discoveries using this powerful instrument.
Observations using Galileo’s version helped us understand the concept of Earth and the planets circling the Sun. The core design of these telescopes was the refracting element. Refractors were used to bend (refract) light and the tube features a concave eyepiece lens and a convex objective lens. The biggest challenge that the inventor faced was finding clear and homogenous glass for the lenses.
Apparently that era saw glasses with little bubbles and greenish tinge due to the iron impurities. Thankfully we have moved past that era and today we can make our own reflector telescopes. Follow the 3-part video below to learn how to make one for yourself.