Lesson 1: Observing The Night Sky Flashcards
Can you explain apparent motions of objects in the night sky?
Our planet is tilted 23.5 degrees. The earth completes one revolution around the sun every 365.4 days. Sun is directly above the equator at the vernal equinox(March 21), above the Tropic of Cancer on the summer solstice(June 21), above the equator on the autumnal equinox(Sept 23), and above the Tropic of Capricorn on the winter solstice(Dec 21).
Can you identify ten constellations and their bright stars?
Ursa Major Ursa Minor - Polaris Cepheus Cassiopeia Andromeda Pegasus Perseus - Algol Lyra - Vega Aquila - Altair Cygnus - Deneb
Reason for the Earth’s four seasons?
Earth’s axis is tilted 23.5 degrees from it’s plane of orbit around the Sun.
Issac Newton made what discovery involving concave mirrors?
They cause the light rays to converge to a focus point.
What is the optimum magnification for an eight-inch telescope?
(8X15) = 120x
What are the two main types of telescopes?
Refracting and reflecting.
True or False: Light changes direction when it changes mediums.
True
Which if the following terms refers to how clear the sky is: Turbulence Fluorescence Transparency Seeing
Transparency
Why can the Hubble Space Telescope (HST) produce better photographs than telescopes on Earth?
Light does not get distorted by the atmosphere.
What is a CCD?
A charge-coupled device.
Which of the following has the entire Electromagnetic Spectrum in the correct order for decreasing wavelength?:
1) violet, blue, green, yellow, orange, red
2) radio, infrared, visible light, ultraviolet, X-Ray, gamma
3) red, orange, yellow, green, blue, violet
4) gamma, X-Ray, ultraviolet, visible light, infrared, radio
2) radio, infrared, visible light, ultraviolet, X-Ray, gamma
What is a photon?
A tiny packet or bundle if energy.
True or False: all electromagnetic waves travel at 300,000 km/sec in a vacuum.
True: all electromagnetic waves travel at the speed of light in a vacuum.
What causes electromagnetic radiation?
Vibrating electrons in an atom. The electrons absorb energy and jump to a higher energy level; because this is highly unstable, the electrons will release energy and revert back to the lower energy state.
Complete the following formula: speed x time = ?
? = Distance
What are the three practical units of measurement for describing the distance from Earth to Proxima Centauri (the nearest star after the Sun)?
The astronomical unit (AU), the light-year, and parsec.
One parsec is equivalent to how many light-years?
3.26
True or False: light leaving the earth would take little more than one second to reach the moon, 400,000 km away.
True
The apparent daily motion of the Sun, Moon, and stars from east to west is caused by…?
Earth’s rotation.
True or False: Reflecting telescopes often suffer from spherical aberration.
True
What is a tiny bundle of electromagnetic energy called?
Photon
True or False: the amount of light collected by a telescope is proportional to the area of it’s aperture(the telescope’s opening).
True
How fast do radio waves travel?
300,000 km/s
On March 21, the Sun is directly above which location?
The Equator
True or False: the biggest telescopes in use today are refracting telescopes.
False: the biggest ones are reflecting telescopes.
Who was the first person to realize that mirrors could be used to construct a telescope?
Issac Newton
The distance from the earth to the Sun has been called…?
The astronomical unit (AU)
What causes the earth to have seasons?
The tilt of Earth’s axis allows direct sunlight to hit different places throughout the year.
True or False: The Hubble Space Telescope gives us much better images than Earth-based telescopes because it is much larger than Earth-based telescopes.
False: HST gives better images because light reaching it doesn’t have to travel through Earth’s atmosphere.
Which of the following electromagnetic waves has the most energy? Visible light Ultraviolet Radio waves Infrared
Ultraviolet
What is the best way to obtain astronomical data?
Use a telescope in space
Two types of telescopes are…?
Refracting and reflecting
True or False: all types if electromagnetic waves travel at the same speed in a vacuum.
True
TRUE OR FALSE: THE NUMBER OF TIMES YOU WILL ORBIT THE SUN IN YOUR LIFETIME WILL BE THE SAME AS THE NUMBER OF DAYS IN YOUR LIFE.
False: as a “passenger” in Earth, you orbit the Sun in the same amount of time that the Earth does. It takes one year for Earth to orbit the Sun, so the number of times you orbit the Sun in your lifetime will be equal to the number of years in your life, not the number of days in your life.
