Light and Telescopes

Page
3

Slide 26

But, we receive GRBs from every direction !!

The fact that GRBs come from every direction imply that GRBs don’t come from our galaxy, but from other galaxies spread in every direction!

Slide 27

Radio wavelength observations are possible from Earth’s surface

Slide 28

The Very Large Array (VLA) in New Mexico

Slide 29

Different types of EM radiation require different types of telescopes

A refracting telescope uses a lens to concentrate incoming light

A reflecting telescope uses mirrors to concentrate incoming starlight

Slide 30

Analyzing Spectra: The Properties of Light

Visible Light is one part of the electromagnetic (EM) spectrum.

EM radiation is described as a wave with wavelengths in the range 1x10-15 m to 100 m.

Visible light is only a tiny small part of the entire electromagnetic spectrum.

Little bits of light are called photons.

Slide 31

Dividing Light Into a Spectrum

Astronomers separate out light into its individual components using a diffraction grating or using a prism - then they analyze each part independently!

Slide 32

81

blue 4600 A 81

Slide 33

blue 4600 A 81

green 5300 A 85

Slide 34

blue 4600 A 81

green 5300 A 85

yellow 5800 A 83

Slide 35

blue 4600 A 81

green 5300 A 85

yellow 5800 A 83

orange 6100 A 78

Slide 36

blue 4600 A 81

green 5300 A 85

yellow 5800 A 83

orange 6100 A 78

red 6600 A 70

The spectrum is continuous.

Slide 37

Spectra

Most light sources contain energy in lots of different wavelengths.

We can measure the brightness in various wavelength bands--the result is called the spectrum.

The spectrum (total character of light emitted) can tell us a lot about a source.

Slide 38