31.1 & 31.2 Flashcards
Refractor telescope
A Refractor uses a convex lens, which curves outward like a ball, to collect and focus visible light. The objective lens collects light and the eyepiece lens magnifies the image.
Reflector telescope
A Reflector uses mirrors to collect and focus visible light. When light passes through the open end of the reflecting telescope, it hits a concave mirror. Often times, a smaller mirror is used to reflect light onto a camera or eyepiece.
Focal point
The focal point of a lens or mirror is the point where parallel light rays converge to produce a clear image. This image can be enlarged with an eyepiece lens. The distance from a lens or mirror to its focal point is called the focal length. The magnifying power of a telescope is equal to the focal length of the objective or mirror lens divided by the focal length of the eyepiece lens.
Adaptive optics
In an adaptive optics system, light from the objective mirror strikes a small, deformable mirror before focusing. A sensor samples the light from the objective mirror to determine how distorted the images are. Then the deformable mirror surface is adjusted many times per second to reduce distortion.
Radio telescopes
Like visible light, radio waves are a form of electromagnetic radiation emitted by stars and other objects in space. Radio waves can be detected even during the day, when the Sun makes it impossible to see faint visible light from other stars, and on cloudy days when the light is obstructed.
Space telescopes
The Earth’s atmosphere absorbs other types of electromagnetic radiation, such as ultraviolet waves, X-rays, and infrared radiation. They produce images using wavelengths that are absorbed by the atmosphere.
Spectroscopes
Visible light from stars can provide information about the composition of the star, its surface temperature, and even how fast it is moving toward or away from Earth. The light produced by stars and other objects in space is made up of different wavelengths of visible light. A spectroscope uses a diffraction grating or prism to separate light into its component wavelengths. The separate wavelengths are called the spectrum of the star. The spectrum can be used to determine the temperature and composition of the star.
Main sequence
They found that the hottest stars produced the most light and energy. Main sequence stars include the broad band of stars from hot, bright stars in the upper left corner of the diagram to cool, faint stars in the lower right corner. All other stars generally fall in three areas on the HR diagram.
Giants and white dwarfs
When equilibrium ends, the core of the star contracts, the temperature rises, and the star becomes a giant star. As the core heats up, the outer layers of the star expand and cold.
Supernova
The collapse of the nucleus releases a large amount of energy and very fast-moving neutrons in the form of a supernova. A supernova is a gigantic explosion in which the temperature inside the collapsing star is 10 billion K and the atomic nuclei in the nucleus are divided into neutrons and protons.
Black holes
Very massive stars, 25 times more massive than the Sun, face a different extreme. In this case, the final collapse of the core continues beyond the neutron star stage and forms a black hole. A black hols is an area in space that is so dense that nothing can escape its force of gravity.
Granules
The photosphere has a grainy appearance. The individual grains are called granules and are about 1,000 km in diameter. The granules are the top of the convection cells. Bright areas are hot material that rises and dark areas are cooler material that sinks.
Sunspots
Sunspots are dark, cool areas in the photosphere where the Sun’s magnetic field has weakened. Temperatures in the center of the sunspot can be 2000 K colder than in its surroundings. Sunspots move as the Sun rotates.
How do constellations get their names?
Characters from stories,animals and tools.
What is the constellations name of the great hunter?
Orion’s belt
