Observing Space: Telescope

Different Forrms of Light; Types of Telescopes; Radio telescope; Telescopes in space; ISRO

Light is a form of electromagnetic wave. Each wave has some characteristic wavelength. Our eyes are sensitive to the light having wavelength between 400 nm to 750 nm and this light is known as visible light. There are other electromagnetic waves with certain wavelengths for which our eyes are not sensitive i.e. they are not visible to naked eyes.
 

DIFFERENT TYPES OF ELECTROMAGNETIC WAVES
Type	Wavelength range
Radio	> 0.1 m
Microwave	0.1 mm to 10 cm
Infra-red	0.4 mm to 750 nm
Light	750 nm to 400 nm
Ultraviolet	400 nm to 1 nm
X-rays	10 nm to 10−2 nm
Gamma rays	<10−2 nm

Different Types of Electromagnetic Waves

Telescope

To see the light radiations coming from space, we have various types of telescopes. Some of them are:

• Optical telescope: These are used only to see visible radiations coming from space.
• X-ray, gamma-ray or radio telescopes: These are used to see radiations other than visible radiations emitted from heavenly bodies in space.

Optical telescope

It is of two types

• Refracting telescope

A refracting telescope with two convex lenses is show…