Celestial Tools and Measurements

Celestial Sphere Imagine a sphere that surrounds our

planet in which all the stars are attached. This sphere is allowed to rotate freely around the planet.

Celestial Equator Located above the Earth’s

Equator

Coordinate Systems

Right Ascension East-West Measurement similar to

longitude Declination

North-South Measurement similar to latitude

Ecliptic Sun’s path relative to the Stars

The angle across the sky a star seems to move in reference to the background of stars between two observations that are 6 months apart.

The measurements are taken when the planet is on opposite sides of the Sun.

Parallax

The farther the star, the harder it is to measure because it doesn’t move very much.

Parallax

Refracting Telescope Uses a combination of lenses to created

a larger image.

Types of Telescopes

Reflecting Telescope Uses mirrors or other types of reflective

surfaces to focus the signals onto a receiver.

Types of Telescopes

Electromagnetic radiation can be described in terms of a stream of photons. These are massless particles each travelling in a wave-like pattern and moving at the speed of light.

Each photon contains a certain amount (or bundle) of energy. The only difference between the various types of electromagnetic radiation is the amount of energy found in the photons.

Radio waves have photons with low energies, microwaves have a little more energy than radio waves, infrared has still more, then visible, ultraviolet, X-rays, and ... the most energetic of all ... gamma-rays.

Electromagnetic Radiation

EM radiation from space is unable to reach the surface of the Earth except visible light, radio wave, and UV light

Astronomers can get above enough of the Earth's atmosphere to “see” the rest of the spectrum.

This is done by building telescopes on mountains, in airplanes, or in satellites.

Electromagnetic Radiation

Electromagnetic Radiation

Radiated by Objects at this temperature: More than 100 000 000

Gamma Rays

Pulsar

Typical Sources Accretion Disks around Black Holes

Gamma Rays

Technology

Gamma Rays

Fermi Gamma Ray Space Telescope

Radiated by Objects at this temperature: 1 000 000 – 100 000 000 k

X-Rays

Typical Sources Gas in Clusters of galaxies; supernova

remnants; stellar corona

X-Rays

Our SunStephan’s Quintet

Technology

X-Rays

Chandra X-Ray Observatory

ROSAT

Radiated by Objects at this temperature: 10 000 – 1 000 000 K

Ultraviolet Rays

New Star Formations

Typical Sources Supernova remnants; very hot stars

Ultraviolet Rays

M81Andromeda

Technology

Ultraviolet Rays

Hubble Telescope

Radiated by Objects at this temperature:

1000 – 10 000 K

Visible Light

Typical Sources Planets; stars; some satellites

Visible Light

Technology Hubble Telescope

Visible Light

Radiated by Objects at this temperature: 10 – 1000 K

Infrared

Typical Sources Cool clouds of dust and gas; planets

Infrared

Sombrero Galaxy

Helix Galaxy

Technology

Infrared

SOFIA

Space Infrared Telescope Facility

Radiated by Objects at this temperature: 1 – 10 K

Microwaves

Typical Sources Cool clouds of gas; including those

round newly formed stars; the cosmic microwave background.

Microwaves

Technology What are the

values of the Big Bang Theory?

How did structures of galaxies form in the Universe?

When did the first structure of galaxies form?

Microwaves

Wilkinson Microwave Anisotropy Probe (WMAP),

Radiated by Objects at this temperature: Less than 1 K

Radio Waves

Typical Sources Radio emissions produced by moving

electrons in a magnetic field.

Radio Waves

Technology

Radio Waves

Arecibo radio observatory

What is the Doppler Effect and how does it relate to stars?)  Why do some stars explode as supernova? What determines its

type of Supernova?   Explain the relationship between the type of death of a star and the

star’s initial mass and size.   Astronomers can learn many things about a star from its spectral

lines? Name three things they can determine from the spectral lines.

How would an increase in mass affect the basic properties of a star?   What is the purpose of the Main Sequence? (3 marks)

Quiz