Describing the Universe

The electromagnetic spectrum and telescopes

What is astronomy?

Astronomy is quite valuable to us humans because of all the new things we have found or is still to be found. This has been a good advantage for us humans because we could predict when an asteroid will hit any of the planets or when is the next huge solar flare. With the help of astronomy, we could have an image on how the solar system was formed or we could see other new solar systems forming. We could also see a new star being born or an old star dying.


1. Identify the visible and non-visible parts of the electromagnetic spectrum.

2. Compare refracting and reflecting telescopes.

3. Explain how telescopes for non-visible electromagnetic radiation differ from light telescopes.

Astronomy Vocabulary

Electromagnetic Spectrum

The electromagnetic spectrum is all the possible frequencies of electromagnetic radiation wavelengths that cannot be seen by the human eye which are infrared waves, microwaves, radio waves, ultraviolet rays, x rays, and gamma rays. There are two types of wavelengths which are either invisible or visible by the human eye.

Visible EM Radiation

A visible electromagnetic spectrum would be white light because when it passes through the prism it is broken into a set of colors which creates rainbows. Visible radiation has a shorter wavelength than red and violet light.

Invisible EM Radiation

An invisible electromagnetic spectrum would be infrared waves, microwaves, radio waves, ultraviolet rays, x rays, and gamma rays which cannot be seen by the human eye but can be seen by using special instruments. Infrared radiation can be read by using a simple thermometer because the heat from thee radiation is read by the thermometer.

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Comparing the Refracting and Reflecting Telescopes

A refracting and reflecting telescope are both used to gather and focus on distant objects to collect information from them from a great distance. With the help of these telescopes, it helped astronomers explore planets, stars, and distant objects far out into space.

A Refracting Telescope is used to gather and focus light from distant objects. These types of telescopes use a special lens that bends light hat passes through and focuses the light and then magnifies it to the eyepiece. The only problem people have with these telescopes is the lens, since the lens has to be large to handle the great amount of strength and clarity required for it to create the image because the size of the lens is dependent to see distant objects.

The Reflecting Telescope is also used to gather and focus on far objects in space but this telescope uses mirrors which is cheaper to make and can be changed without affecting the telescopes image quality. These telescopes use two mirrors, when starlight enter the telescope he light is reflected onto the curved mirror and then reflected onto a second mirror under the eyepiece where you can see the image. These telescopes can be up to 10m in diameter which is the largest in the world.

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Invisible Light Telescope

Refracting and reflecting telescopes are used to collect and study visible light. Although visible light provides valuable information, it only represents a tiny portion of the electromagnetic spectrum. To see the rest of the spectrum, which consists of invisible colors, researchers need to use telescopes that are capable of detecting wavelengths that to the corresponding type of light. Invisible light telescopes usually detect Infrared radiation because it is the light we see from the sun.

Space Based Telescope

Light travels in waves and these are read by a type of telescope that observe the light by passing it through the tube of the telescope. It then reflectes on the second mirror which then bends the light waves upward to make the image. Space telescopes have been a big help to us human because ground-based telescopes cannot see as much because of the atmosphere. The Hubble telescope is in space and has been able to capture clear images than the ones taken on earth.