Astronomy. My first Year Notes
written by Kirstie Calderon Lewis
My own notes of Astronomy First Year lesson 1 - 9. All notes from the lessons and my own work on Astronomy. Important information for quizzes and essays can be find within the notes.
Last Updated
05/31/21
Chapters
9
Reads
916
Lesson Two
Chapter 2
Telescopes
• A telescope is an optical instrument that magnifies a distant object and makes it appear brighter.
• By examining the colour of light from distant galaxies with the 100-inch-wide Hooker telescope, then the biggest one in existence, an American astronomer Edwin Hubble was able to conclude that the universe is expanding, initiating the branch of astronomy called cosmology, which studies the origin and evolution of the universe. More information about Hubble can be found here.
• The earliest telescopes had two lenses at opposite ends of a tube. At the far end of the tube is the light-gathering lens, called the objective lens. This lens is convex. The positive lens.
• To make them appear sharp, you need another lens at the near end of the tube, called the eyepiece. The negative lens.
• This was the design of the first Muggle telescope, invented by Hans Lippershey, a Dutch eyeglass maker, in 1608.
• Galileo Galilei, a famous astronomer, improved on that design. He found that by making the objective lens less curved, he could improve the magnifying power from three to 20, making it a more useful astronomical tool.
• He used it to discover the four largest moons of Jupiter, which are therefore called the Galilean moons.
• He also discovered that Venus has phases like the Moon, confirming Copernicus’s belief that the Earth revolves around the sun rather than the other way around.
• Any telescope whose eyepiece is a negative lens is now called a Galilean telescope.
• Galilean telescope narrow field of view allow being able to see a small part of the sky.
• Johannes Kepler found that if the eyepiece is also a positive lens, you can see much more of the sky. This is called an astronomical telescope; everything appears upside down.
• All three types of telescopes have been altered and improved in order to enable the user to adjust the focus.
• In the terrestrial telescope, the magnifying power can be adjusted too - the farther apart the two lenses of the eyepiece are, the greater the magnifying power. With the astronomical type, you have to change the eyepiece in order to change the power, but astronomers are prepared to do that rather than have an extra lens, which absorbs a bit of the precious light they need for their observations.
• Telescopes that use only lenses are called refracting telescopes.
• Modern refracting telescopes use several lenses in the eyepiece to solve that problem, but in 1688, Isaac Newton solved it by using mirrors instead of lenses – he invented the reflecting telescope, so called because mirrors reflect light – so telescopes that use his design are called Newtonian telescopes.
• Telescope magnifies distant objects is called the telescope’s power. the weaker the objective lens or mirror is and the stronger the eyepiece is, the more powerful the telescope will be.
• Advantage of making the objective lens or mirror bigger is that it improves the resolution of the telescope. How close together two points of light can appear to be and still be seen as two distinct points instead of one. The observed closeness of two points of light is measured as an angle, not a straight-line distance.
• The ancient Greeks divided the circle into 360 degrees.
• Someone with average vision can, at best, distinguish two points of light about 1/20th of a degree apart with the naked eye. However, astronomers have a need to see objects that appear much closer together than that. Rather than writing many tiny fractions of a degree to describe the observed closeness between two stars, they use even smaller units known as arcminutes and arcseconds.
• A degree is divided into 60 arcminutes and an arcminute is divided into 60 arcseconds.
• The biggest one so far is the Keck telescope, 10 meters in diameter
• The problem is that movement of the air makes the stars appear to move around (and twinkle too), making it hard to achieve a resolution much better than one arcsecond no matter how big the telescope is. Large modern telescopes solve this problem by using what is called adaptive optics, in which the mirror deforms hundreds of times per second to compensate for the apparent movement of the stars.
Satellites
• A satellite of a planet is an object that is in orbit around the planet. Moons are natural satellites, whereas an artificial satellite is a man-made object launched into orbit by means of a rocket.
• Muggles have what is called a GPS (Global Positioning System) that uses satellites to locate the position of a receiver.
• Satellites are also used for communication, like telephone, television, internet transmission, looking at photograph of the Earth, to examine clouds, temperature and rainfall to make accurate weather forecasts, and to put telescopes above the atmosphere.
• The Hubble telescope, named after Edwin Hubble, is one such telescope orbiting Earth. It is about 2.5 meters wide, so it should be able to resolve two stars that are 0.05 arcseconds apart. But when it was launched in 1990, its resolution was more than one arcsecond! Astronauts was sent up in 1993 to correct the problem. Resolution improved to the expected 0.05 arcseconds. Many important discoveries, including finding distant galaxies and black holes.
• Satellites also house other tools like cameras, radars, and remote sensors, tools to collect and analyse space particles and carry people. They house other tools like cameras, radars, and remote sensors, tools to collect and analyse space particles, and more that give us other important information. Some of them also carry people, which serves to arouse public interest in space travel and increase the prestige of the country that launches them. The space race between the United States and the Soviet Union during the Cold War between those two nations is a prime example.
• Sputnik - The first satellite, a Russian word meaning “fellow traveller” - was launched in 1957 by the Soviet Union.
• United states launched their first satellite, four months later, Explorer 1.
• The Soviet Union had already launched their second satellite, which carried a dog named Laika.
• The Soviet Union launched their third satellite, which carried the first man into outer space – Yuri Gagarin, grandfather of Professor Gagarina.
• The Americans responded in 1958 by creating the National Aeronautics and Space Administration (NASA) to catch up with the Soviet Union in the space race.
• The United States finally won the space race in 1969 when they landed two men, Neil Armstrong and Buzz Aldrin, on the Moon.
• The soviet Union launched a woman into space, in 1963 Valentina Tereshkova, spend three days in space.
• Twenty years were to pass before the Americans first launched a woman into space, Sally Ride. NASA no longer takes gender into consideration in evaluating candidates for space travel.
• Spacecraft have orbited other celestial bodies besides Earth and our moon; in fact they have orbited all the planets, some of their moons (like Saturn’s biggest moon Titan), and some asteroids and comets, and have given astronomers much information about them.
Space Agencies in Other Countries.
• Several European countries contribute to the European Space Agency, and there are space agencies in numerous other countries including Canada, India, Japan, and China. Sometimes they go it alone.
• China National Space Administration first landed a rocket on the far side of the Moon on January 3, 2019
• Wizards have actually worked under cover with those other space agencies, but not in NASA. In 1790 MACUSA, the American equivalent of the British Ministry of Magic, passed Rappaport’s Law, an edict enforcing total segregation between magical people and No-Majs (the American name for Muggles).
• Canada invented the Canadarm, a robot that is attached to an artificial satellite and used to deploy, maneuver, and capture payloads.
Space Shuttles
• In the early 1980s, NASA began a program called the Space Transportation System, using artificial satellites, called space shuttles.
• They were used to launch numerous other satellites, interplanetary probes, and the Hubble Space Telescope to conduct science experiments in orbit and to participate in the construction and servicing of the International Space Station.
• There were two accidents on space shuttles, which killed a total of 14 astronauts. The program was terminated in 2011.
• Since then the United States has been relying on the Russian spacecraft Soyuz to transport astronauts and supplies to and from the International Space Station.
• The United States is working on a couple of new programs, which are on schedule for first flights in 2019 and 2020.
• The first unmanned flight was docked with the International Space Station on March 3, 2019 and brought supplies to the three astronauts on board.
Radar
• Radar as a device used by the military to detect enemy planes and missiles.
• Radar is a detection system that uses radio waves or microwaves to determine the range, angle, or velocity of objects.
• Besides military: air and ground traffic control, locating landmarks and ships at sea, ocean surveillance, monitoring the weather, geological observations, and (our subject of interest) radar astronomy.
• Many astronomical objects have been studied by radar: the Moon, Venus, Mars, Mercury, the four biggest moons of Jupiter, Saturn’s rings and its largest moon, Titan, and a few nearby asteroids and comets.
• Astronomers get information about the surface of these objects, which we wizards then find useful in our study of how they affect our magic.
Rovers
• A rover is a vehicle designed to move across the surface of a planet or a moon.
• Rovers have only been landed on the Moon and Mars, and all of them but one - Yutu, a Chinese lunar rover. Were launched either by the United States or Russia. One of those rovers, called Curiosity, launched by the United States.
• If a rover can be driven from the Earth, the driver can decide at any moment what is the most interesting place for it to visit.
• A signal does not arrive at its destination the instant it is sent; it travels at the speed of light, which is very fast, but if the distance between the source and the destination is too great, the delay makes driving a rover from the Earth impractical.
• A telescope is an optical instrument that magnifies a distant object and makes it appear brighter.
• By examining the colour of light from distant galaxies with the 100-inch-wide Hooker telescope, then the biggest one in existence, an American astronomer Edwin Hubble was able to conclude that the universe is expanding, initiating the branch of astronomy called cosmology, which studies the origin and evolution of the universe. More information about Hubble can be found here.
• The earliest telescopes had two lenses at opposite ends of a tube. At the far end of the tube is the light-gathering lens, called the objective lens. This lens is convex. The positive lens.
• To make them appear sharp, you need another lens at the near end of the tube, called the eyepiece. The negative lens.
• This was the design of the first Muggle telescope, invented by Hans Lippershey, a Dutch eyeglass maker, in 1608.
• Galileo Galilei, a famous astronomer, improved on that design. He found that by making the objective lens less curved, he could improve the magnifying power from three to 20, making it a more useful astronomical tool.
• He used it to discover the four largest moons of Jupiter, which are therefore called the Galilean moons.
• He also discovered that Venus has phases like the Moon, confirming Copernicus’s belief that the Earth revolves around the sun rather than the other way around.
• Any telescope whose eyepiece is a negative lens is now called a Galilean telescope.
• Galilean telescope narrow field of view allow being able to see a small part of the sky.
• Johannes Kepler found that if the eyepiece is also a positive lens, you can see much more of the sky. This is called an astronomical telescope; everything appears upside down.
• All three types of telescopes have been altered and improved in order to enable the user to adjust the focus.
• In the terrestrial telescope, the magnifying power can be adjusted too - the farther apart the two lenses of the eyepiece are, the greater the magnifying power. With the astronomical type, you have to change the eyepiece in order to change the power, but astronomers are prepared to do that rather than have an extra lens, which absorbs a bit of the precious light they need for their observations.
• Telescopes that use only lenses are called refracting telescopes.
• Modern refracting telescopes use several lenses in the eyepiece to solve that problem, but in 1688, Isaac Newton solved it by using mirrors instead of lenses – he invented the reflecting telescope, so called because mirrors reflect light – so telescopes that use his design are called Newtonian telescopes.
• Telescope magnifies distant objects is called the telescope’s power. the weaker the objective lens or mirror is and the stronger the eyepiece is, the more powerful the telescope will be.
• Advantage of making the objective lens or mirror bigger is that it improves the resolution of the telescope. How close together two points of light can appear to be and still be seen as two distinct points instead of one. The observed closeness of two points of light is measured as an angle, not a straight-line distance.
• The ancient Greeks divided the circle into 360 degrees.
• Someone with average vision can, at best, distinguish two points of light about 1/20th of a degree apart with the naked eye. However, astronomers have a need to see objects that appear much closer together than that. Rather than writing many tiny fractions of a degree to describe the observed closeness between two stars, they use even smaller units known as arcminutes and arcseconds.
• A degree is divided into 60 arcminutes and an arcminute is divided into 60 arcseconds.
• The biggest one so far is the Keck telescope, 10 meters in diameter
• The problem is that movement of the air makes the stars appear to move around (and twinkle too), making it hard to achieve a resolution much better than one arcsecond no matter how big the telescope is. Large modern telescopes solve this problem by using what is called adaptive optics, in which the mirror deforms hundreds of times per second to compensate for the apparent movement of the stars.
Satellites
• A satellite of a planet is an object that is in orbit around the planet. Moons are natural satellites, whereas an artificial satellite is a man-made object launched into orbit by means of a rocket.
• Muggles have what is called a GPS (Global Positioning System) that uses satellites to locate the position of a receiver.
• Satellites are also used for communication, like telephone, television, internet transmission, looking at photograph of the Earth, to examine clouds, temperature and rainfall to make accurate weather forecasts, and to put telescopes above the atmosphere.
• The Hubble telescope, named after Edwin Hubble, is one such telescope orbiting Earth. It is about 2.5 meters wide, so it should be able to resolve two stars that are 0.05 arcseconds apart. But when it was launched in 1990, its resolution was more than one arcsecond! Astronauts was sent up in 1993 to correct the problem. Resolution improved to the expected 0.05 arcseconds. Many important discoveries, including finding distant galaxies and black holes.
• Satellites also house other tools like cameras, radars, and remote sensors, tools to collect and analyse space particles and carry people. They house other tools like cameras, radars, and remote sensors, tools to collect and analyse space particles, and more that give us other important information. Some of them also carry people, which serves to arouse public interest in space travel and increase the prestige of the country that launches them. The space race between the United States and the Soviet Union during the Cold War between those two nations is a prime example.
• Sputnik - The first satellite, a Russian word meaning “fellow traveller” - was launched in 1957 by the Soviet Union.
• United states launched their first satellite, four months later, Explorer 1.
• The Soviet Union had already launched their second satellite, which carried a dog named Laika.
• The Soviet Union launched their third satellite, which carried the first man into outer space – Yuri Gagarin, grandfather of Professor Gagarina.
• The Americans responded in 1958 by creating the National Aeronautics and Space Administration (NASA) to catch up with the Soviet Union in the space race.
• The United States finally won the space race in 1969 when they landed two men, Neil Armstrong and Buzz Aldrin, on the Moon.
• The soviet Union launched a woman into space, in 1963 Valentina Tereshkova, spend three days in space.
• Twenty years were to pass before the Americans first launched a woman into space, Sally Ride. NASA no longer takes gender into consideration in evaluating candidates for space travel.
• Spacecraft have orbited other celestial bodies besides Earth and our moon; in fact they have orbited all the planets, some of their moons (like Saturn’s biggest moon Titan), and some asteroids and comets, and have given astronomers much information about them.
Space Agencies in Other Countries.
• Several European countries contribute to the European Space Agency, and there are space agencies in numerous other countries including Canada, India, Japan, and China. Sometimes they go it alone.
• China National Space Administration first landed a rocket on the far side of the Moon on January 3, 2019
• Wizards have actually worked under cover with those other space agencies, but not in NASA. In 1790 MACUSA, the American equivalent of the British Ministry of Magic, passed Rappaport’s Law, an edict enforcing total segregation between magical people and No-Majs (the American name for Muggles).
• Canada invented the Canadarm, a robot that is attached to an artificial satellite and used to deploy, maneuver, and capture payloads.
Space Shuttles
• In the early 1980s, NASA began a program called the Space Transportation System, using artificial satellites, called space shuttles.
• They were used to launch numerous other satellites, interplanetary probes, and the Hubble Space Telescope to conduct science experiments in orbit and to participate in the construction and servicing of the International Space Station.
• There were two accidents on space shuttles, which killed a total of 14 astronauts. The program was terminated in 2011.
• Since then the United States has been relying on the Russian spacecraft Soyuz to transport astronauts and supplies to and from the International Space Station.
• The United States is working on a couple of new programs, which are on schedule for first flights in 2019 and 2020.
• The first unmanned flight was docked with the International Space Station on March 3, 2019 and brought supplies to the three astronauts on board.
Radar
• Radar as a device used by the military to detect enemy planes and missiles.
• Radar is a detection system that uses radio waves or microwaves to determine the range, angle, or velocity of objects.
• Besides military: air and ground traffic control, locating landmarks and ships at sea, ocean surveillance, monitoring the weather, geological observations, and (our subject of interest) radar astronomy.
• Many astronomical objects have been studied by radar: the Moon, Venus, Mars, Mercury, the four biggest moons of Jupiter, Saturn’s rings and its largest moon, Titan, and a few nearby asteroids and comets.
• Astronomers get information about the surface of these objects, which we wizards then find useful in our study of how they affect our magic.
Rovers
• A rover is a vehicle designed to move across the surface of a planet or a moon.
• Rovers have only been landed on the Moon and Mars, and all of them but one - Yutu, a Chinese lunar rover. Were launched either by the United States or Russia. One of those rovers, called Curiosity, launched by the United States.
• If a rover can be driven from the Earth, the driver can decide at any moment what is the most interesting place for it to visit.
• A signal does not arrive at its destination the instant it is sent; it travels at the speed of light, which is very fast, but if the distance between the source and the destination is too great, the delay makes driving a rover from the Earth impractical.
