Tools of Astronomy

Radiation and the Electromagnetic Spectrum Electromagnetic Radiation (ER) is a form of energy that is emitted and absorbed by charged particles and exhibit wave-like behaviour All energies in the Universe may be described on the electromagnetic spectrum. ER possesses electric and magnetic field components All ER travel at the speed of light (c = 3.00 x 108 m/s)

Light behaves like a wave Light behaves like a particle

Electrometric Spectrum

Using and Calculating Wavelength ER is classified by their wavelength (distance between wave crests) and is described by lambda (λ)

Using and Calculating Wavelength ER is also classified by their frequency (number of waves that pass a given point per second) and is measured in Hertz (Hz; cycles per second)

Relating Speed, Frequency and Wavelength c = f λ c = Speed of light = 3.00 x 108 m/s f= frequency = measured in cycles per second; Hertz (Hz) λ = wavelength = measured in meters

Telescopes “Tele” - far “Scope” – to look An instrument that is used to observed remote objects by collecting ER.

1. Refracting Telescope Refraction refers to the bending of light Gather and focus light on a focal point (focus)

2. Reflecting Telescope Reflecting refers to bouncing rays of light Designed to allow for very large diameter objectives

Interferometry and the Effect of Technology A family of techniques / instruments / surveyed information that may be combined and superimposed to uncover relationships between different types of ER

Hubble Space Telescope Was launched in 1990 Named after Edwin Hubble (astronomer responsible for confirming the existence of galaxies outside of the Milky Way) 2.4-meter aperture telescope Able to detect near UV light, visible spectrum, and near IR

Hubble Space Telescope Within weeks of launch, images observed back on Earth were of poor quality The primary mirror had been incorrectly mounted The problem was corrected in 1993 with the addition of another mirror

Chandra X-ray Observatory Launched July, 1999 Named after Subrahmanyan Chandrasekhar (astrophysicist; Nobel Prize winner for describing processes significant to the structure and evolution of stars) Able to detect X-ray radiation

Try This Finish frequency/wavelength worksheet p. 769 Q:1-4