Telescopes and Space Probes
How telescopes gather and magnify light, the difference between refractors and reflectors, and how space probes explore the Solar System, from fly-bys to landers.
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Two ways to explore space 🔭
We explore the Solar System in two ways: by looking out from Earth with **telescopes**, and by sending robotic **space probes** to visit other worlds. This module covers how a telescope gathers and magnifies light, the difference between the two main telescope designs, and the kinds of space probe we send and why.
The parts of a telescope 🔑
A few key ideas describe how any telescope works:
Match each part 🔗
- Objective
- Eyepiece
- Aperture
- Resolution
- The main lens or mirror that gathers the light
- The small lens you look through to view the image
- The diameter of the objective, setting the light gathered
- The ability to see fine detail and separate close objects
Refractors and reflectors ⚖️
There are two main telescope designs, and they gather light in different ways.
Lenses or mirrors? 🪞
Which type of telescope uses MIRRORS to gather light?
- A reflector
- A refractor
- A Galilean telescope
- A Keplerian telescope
Work out the magnification 🧮
An interactive activity.
Why aperture matters 💡
The **aperture** is the diameter of the objective, and it controls the telescope's **light grasp**. Light grasp is proportional to the diameter **squared**, so doubling the aperture gathers **four times** as much light. A larger aperture also gives better **resolution**, letting you see finer detail. That is why the biggest research telescopes are built with huge mirrors.
Why choose a reflector? ✅
Select the TWO advantages of a reflector over a refractor.
- It does not suffer from chromatic aberration
- It can be made much larger and more cheaply
- It can only ever be built very small
- It uses lenses and no mirrors at all
Telescopes in words 🧱
The main light-gathering lens or mirror is the _____, and the small lens you look through is the _____. The diameter of the objective is the _____; a bigger one gathers more light. A telescope that uses lenses is a _____, while one that uses mirrors is a _____.
Match each space probe 🛰️
- Fly-by
- Orbiter
- Impactor
- Lander
- Passes close to a body once, then flies on, like New Horizons at Pluto
- Goes into orbit to study a body over time, like Juno at Jupiter
- Deliberately crashes into a body, like the Deep Impact probe
- Touches down on the surface, like Philae on a comet
Name that probe 🚀
A probe that goes into orbit around a planet to study it over a long time is called what?
- An orbiter
- A fly-by
- A lander
- An impactor
Why send a robot? 🖍️
An interactive activity.
Through the telescope 🪜
An interactive activity.
Plan the exploration 🧭
An interactive activity.
Crewed or robotic? ✍️
An interactive activity.