~Telescopes

-Telescope: An optical instrument that magnifies a distant object and makes it appear brighter
-Astronomy's most important tool
-Used to discover Uranus, Neptune, and Pluto
-Muggle astronomers have used them to discover new asteroids, comets, stars, galaxies, moons, and even planets orbiting stars
-By examining the color of light from distant galaxies with the 100-inch-wide Hooker telescope, then the biggest one in existence, an American astronomer Edwin Hubble discovered that the universe is expanding, initiating the branch of astronomy called cosmology, which studies the origin of the universe.
-A truly invaluable tool
-Earliest ones had 2 lenses at opposite ends of a tube.
-The far end of the tube is the light-gathering lens(the objective lens). It's convex(like a magnifying glass) and called a positive lens.
-Other end of the tube is the eyepiece, which was a convex lens in earlier days(and a negative lens).
-First Muggle telescope invented by Hans Lippershy(a Dutch eyeglass maker) in 1608
-Made distant objects look 3x bigger
-2 years later, Galileo Galilei, a famous astronomer, improved on the design. 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. Used it to discover the four largest moons of Jupiter, which are 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 has a narrow point of view though
-Johannes Kepler discovered that if the eyepiece is also a positive lens, you can see more of the sky. This kind of telescope is called an astronomical telescope.
-Everything you look at is upside down but that doesn't matter much since you can adjust.
-Terrestrial telescope: telescope where the eyepiece has two positive lenses; the one closest to your eye turns what you see right side up again. Popular among people who want to see things on Earth(Ex: Ship navigators)
-All telescopes have been altered and improved so you can adjust their focus
-In newer models there're 2 tubes instead of 1: a wide tube that has the objective lens, and a narrower tube, which can be slid in or out, that has the eyepiece.
-In the terrestrial telescope, the magnifying power can be adjusted - the farther apart the two lenses of the eyepiece are, the greater the magnifying power is.
-With the astronomical telescope, you have to change the eyepiece in order to change the power, but astronomers will to do that rather than have an extra lens, which absorbs a bit of the light they need for their observations.
-Refracting telescope: Telescopes that only have lenses(since lenses refract light)
-In 1688, Isaac Newton modified the refracting telescope by using mirrors instead of lenses(a reflecting telescope, or Newtonian Telescope).
-Telescope power: the amount by which a telescope magnifies distant objects
-The weaker the lens/stronger the eyepiece, the more powerful a telescope is
-The amount of light a telescope gathers depends on the focus' area, not its diameter
-Squares of numbers
-making the objective lens or mirror bigger improves the resolution of the telescope
-The observed closeness of two points of light is measured as an angle, not a straight-line distance.
-Ancient Greeks divided the circle into 360 degrees. If 1 star is on the east horizon and 1 is on the west, it's a 180 degree angle
-A degree is divided into 60 arcminutes and an arcminute is divided into 60 arcseconds.
-If you double the diameter of the objective lens or mirror, you double the resolution
- The biggest telescope so far is the Keck telescope, 10 meters in diameter.

~Satellites

-Satellite: An object that is in orbit around the planet
-Moons are natural satellites
-Artificial satellite: man-made object launched into orbit. Many purposes.
-Muggles can track position of receiver with a Global Positioning System(GPS).
-Satellites are used for communication, photography, weather forecasts, and astronomy contributions.
-The Hubble telescope, named after Edwin Hubble, is a telescope orbiting Earth. About 2.5 meters wide, so it should be able to resolve two stars that are 0.05 arcseconds apart.
-When it was launched in 1990, the resolution was more than 1 arcsecond! A team of astronauts was sent in 1993 to correct a problem in the primary mirror, after which the resolution improved to 0.05 arcseconds.
-It's made many important discoveries since then such as distant galaxies, black holes, the rate at which the universe expands, and estimating more precisely the age of the universe.
-Some satellites carry people
-1st satellite called Sputnik(Russian for fellow traveler) launched in 1957 by Soviet Union
-4 months later, the US launched its 1st satellite(Explorer 1) and the Soviet Union launched a 2nd satellite(that carried a dog named Laika) during those 4 months
-Shortly after, the Soviet Union launched a 3rd satellite which carried the 1st man into outer space(Yuri Gagarin, grandfather of Professor Gagarina)
-Since satellites can be used to spy, the US created NASA(National Aeronautics and Space Administration) in response to the Soviets and to catch up
-US won Space Race in 1969 when they landed Neil Armstrong and Buzz Aldrin on the moon and brought them back down to Earth
-Soviet Union sent 1st woman into space(Valentina Tereshkova) in 1963 who spent 3 days in space
-Americans launched their 1st woman into space(Sally Ride) 20 years later
-Spacecraft have orbited all planets, and some moons and asteroids/comets and provided valuable information

~Space Agencies In Other Countries

-Several European countries contribute to European Space Agency
-There are space agencies in many other countries such as Canada, India, Japan, and China.
-China National Space Administration landed rocket on far side of moon Jan. 3, 2019
-Americans, Russians, Europeans, Canadians, and Japanese cooperated to build the International Space Station, which is also a satellite, and often houses people from more than one country at same time.
-Some wizards have worked undercover in space agencies(not NASA though, due to 1790 American Ministry equivalent edict enforcing total segregation between magical people and No-Majs(Rappaport's Law)

~Space Shuttles

-NASA began Space Transportation System in early 1980s
-Space Shuttle: Artificial satellites that are partially or totally reusable
-Used to launch numerous other satellites, probes, and the Hubble Space Telescope for research purposes
-there were 2 shuttle accidents, killing a total of 14 astronauts.
-program terminated in 2011
-US has been relying on Russian spacecraft Soyuz to transport astronauts/supplies to/from the Int.l Space Station

~Radar

-Radar: Detection system using microwaves or radio waves to determine weight, size, or velocity of objects
-bounces waves off objects and studies those reflected by object
-Besides military, uses include air/ground traffic control, locating landmarks/ships at sea, ocean surveillance, weather monitoring, geology observations, and radar astronomy.
-Astronomical objects studied by radar include: the Moon, Venus, Mars, Mercury, the four biggest moons of Jupiter, Saturn’s rings and its largest moon, Titan, and a few asteroids and comets.

~Rovers

-Rover: Vehicle designed to move across surface of planets/moons.
-Some designed to carry people
-Some are robots
-Used to study planet or moon they are planted on by taking pictures, readings of the atmosphere, or samples of rocks/dirt.
-So far, they've been landed on the moon and Mars
-All landed rovers launched by either Russia or US(except Yutu, a Chinese lunar rover)
-1 rover, called Curiosity, launched by the US, is currently looking for evidence of past/present life on Mars and generally trying to determine whether the planet could ever have supported life
-Can be driven from Earth but can be impractical if signal takes too long(4-24 min.s)

~Assignments

-A mandatory quiz, which will require external research for 1 of the questions
-An optional extra-credit essay requiring you to summarize information from a separate source