Telescope

Telescope and it’s applications

Do you remember the time you’d sit on your bed pretending to steer an imaginary ship? Your younger siblings used to yell, “Aye, Captain!” while you did your best imitation of Popeye. You’d roll a newspaper and peer out of one end spotting a whale through your makeshift telescope. And then one fine day, you were thrilled (maybe not so thrilled!) to discover what exactly a telescope is? Well Watson, time for us to show to the young ones (siblings, kids or cousins) interesting things about the telescope!

What is a telescope?

It is an optical instrument designed to make distant objects appear larger. It contains an arrangement of lenses, or curved mirrors and lenses, by which rays of light are collected and focused. The resulting image gets magnified.

On the lighter note, it’s a tube with two lenses that makes you see objects that are faaaaar away (yep, that far, really!) and makes them look BIG (yep, that big too!). Without this tube, the objects would be just little dots in the sky or the sea. Since I know you’re already rolling your eyes at me, so I promise to be all so serious as I describe the telescope.

Telescope

Telescope

How a Telescope Works

When you hold a magnifying glass a few inches away from a notebook page, the words on the page appear magnified. When you look at a distant object through the same magnifying glass, you see an upside-down image of the object.

Astronomical telescope

An astronomical telescope makes use of two lenses, one of which works in each of these ways. The lens in the front of the telescope (the objective lens) produces an upside-down image of the object. The lens near the eye (the eye lens) magnifies that upside-down image. As a result, you see distant objects closer.

Telescope

Astronomical telescope

Optical telescope

An optical telescope however, gathers and focuses light from the visible part of the electromagnetic spectrum, to create a magnified image.

Telescope

Optical telescope

There are 3 primary types of optical telescope:

  • Refractors, which use lenses
  • Reflectors, which use mirrors
  • Catadioptric telescopes, which use a combination of both lenses and mirrors

These telescopes increase the apparent size of distant objects as well as their apparent brightness.

History

          The first optical telescope was basically constructed by the lens-grinder Dutchman, Hans Lippershey in 1608. Interestingly, Galileo Galilei is sometimes wrongly credited with its invention. He built the first astronomical telescope from a tube containing two lenses of different focal lengths aligned on a single axis in the following year.

Galileo's Telescope

Galileo’s Telescope

With this telescope, he made the first telescopic observations of the sky. He discovered lunar mountains, four of Jupiter’s moons and sunspots. We learnt that Saturn had rings and that the Milky Way was not a cloud but a collection of stars! It was a revolution in the scientific world!! The secrets of the heavens finally seen! Since then, telescopes have increased in size and improved in image quality. Computers are now used to take photographs of the observations made with the help of telescopes.

Now that we know what the lens / mirror tube is all about and who made it, why not also discover what it does?

Applications of telescopes

  • They are used by astronomers most importantly, to discover the cosmic world in great detail. The Hubble telescope was used to discover galaxies beyond our own.
  • Before GPS, radar and sonar, the humble telescope was used to spot land by navigators in a ship. It was also used by merchant ship sailors, explorers and pirates. (Arrrr!!).
  • Telescopes are basically also used by ornithologists (bird scientists) for spotting rare birds from far away.

I sometimes wonder how astonishing it must’ve been for astronomers – to peer through a telescope and glimpse the true beauty of the heavens! The explorers of the past have relied on this invention to help them sail through uncharted waters. The telescope truly changed the way we humans viewed the world!

Oh and before I sign off, do check out this cool kit at (link) to make your own telescope!

We love to assist our visitors, students, parents in their quest to learn science, you are welcome to leave your questions / comments. Chat with us, use contact us from here or on our facebook page (www.facebook.com/projectsforschool/). In conclusion, drop us an email for any other queries and we would certainly reply with an answer to your queries!!

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