Exploring the Planets: Telescopes

Refracting

Bending of light as it travels from one transparent medium to another

Reflecting

Light hits a surface and bounces back

Refracting glass lens telescope

Gathers and concentrates a beam of light through a series of glass prisms into one focus point

Reflecting telescopes

Uses a curved mirror to reflect a large beam of light into one focus point

Why reflecting telescopes are better

1. refractors can refract light differently based on wavelength 2. Refractors absorb some light, leading to lower resolution 3. Need large lenses that can be very heavy 4. Need 2 polished sides while reflectors only need 1

Keck telescopes

Huge reflective telescopes in Hawaii located high up on a mountain so they are above weather

Hubble telescope

Reflecting telescope located just outside earth's atmosphere that measures ultraviolet, visible and near-infrared regions of the electronegative spectrum

(Size) telescope=____light gathered=____resolution

Bigger, more, better

Resolving power

When better, it can distinguish objects closer together and see more detail

Atmospheric blurring

Air movement interaction with photons of light that can slightly distort an image we see from earth on a telescope

Radio telescopes

Capture radio waves and so are not effected by weather of atmospheric blurring, very large to pick up faint radio waves from deep space, have poor angular resolution

Interferometry

Using several widely spread radio telescopes pointing at the same place in the sky and capturing the waves with constructive interference to act as one giant telescope

Infrared telescopes

Give us an image when visible light is blocked eg a dust cloud obscures our view of a planet

Ultraviolet telscopes

Must be used in space as UV light does not reach earth's surface

X-ray telescopes

We must assign colour to different wavelengths becaue it does not produce any colour

Gamma telescopes

Cannot be focused with such intense energy so all images are blurry/coarse

James Webb space telescope

Orbits the sub 1.5 million km away and designed to study infrared parts of the universe, has a 6.5 m mirror