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who came up with the magnitude scale? |
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what is the equation to determine the intesity ratio of two stars with different magnitudes? |
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subtract the larger magnitude (dimmer) from the smaller magnitude and enter it into calculator as 2.512 ^ (answer from subtraction) |
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what is the equation to determine the magnitude difference of two stars? |
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enter in calculator: LOG(dimmer star/brighter star) and multiple this by 2.512 |
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by their Greek letter for brightness in that constellation (alpha=brightest, beta=2nd brightest) |
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At what magnitude do we start to have difficulty seeing stars? |
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what's ano word for zenith? |
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what's ano word for zenith? |
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altitude above the horizon |
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it goes North to South and splits the sky east and west |
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90 degrees from the zenith |
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the distance light can travel in a year (about 10 trillion km) |
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how many arcminutes are in one degree? |
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how many arcseconds are in an arcminute? |
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what is one finger about equivalent to in degrees? |
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what is a fist about equivalent to in degrees? |
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what is a stretched out palm about equivalent to in degrees? |
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You live at a latitude of 73° N. What is the angle between the northern horizon and the north celestial pole? |
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Where in the sky (North, South, East, or West) would stars appear to be moving counterclockwise at the north pole? |
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Where in the sky (North, South, East, or West) would stars appear to be moving upwards (rising) at the north pole? |
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Where in the sky (North, South, East, or West) would stars appear to be moving in a rainbow-shaped motion at the north pole? |
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how much of the night sky is north of the celestial equator? |
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to what degree is our earth's axis tilted? |
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the "wobble" of the earth's rotation that occurs about every 26,000 years |
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the sun's apparent path on the sky |
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What DOES NOT contribute to the changes in the seasons? |
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the "distance" from the sun |
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What does determine the seasons? |
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the amount of sun and the angle of the sun (more direct sunlight/longer day=warmer) |
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the point when the earth is closest to the sun |
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the point when the earth is furthest from the sun |
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What three factors contribute to the Milankovich hypothesis? |
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Eccentricity of Earth’s orbit around the Sun (varies over period of ~100,000 years) • Precession (period of ~26,000 years) • Inclination of Earth’s axis versus orbital plane |
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what IS the Milankovich Hypothesis? |
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Changes in all three of the factors are responsible for long-term global climate changes (ice ages) |
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All planets in almost circular (elliptical) orbits around the Sun, in approx. the same plane (ecliptic) AND Sense of revolution: counter-clockwise |
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Which planets are almost never visible with the naked eye? |
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about when would you see Mars? |
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shortly after sunset or shortly before sunrise for a short while |
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about when would you see Venus? |
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for a few hours after sunset or before sunrise |
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The moon has an angular diameter of 0.5°. What is the moon's angular diameter in minutes of arc? |
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If you were standing on the moon, what phase would the earth be in? |
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the opposite of the moon (if it's a new moon, it's a full earth, etc.) |
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in what direction does the moon across the sky? |
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eastward (rises in the west) |
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at about what time does a last quarter (3rd quarter) moon rise? |
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The ____ moon is visible above the eastern horizon a couple of hours before sunrise. |
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how long is the synodic period? |
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29.5 days (how long it takes the moon to reach the same spot relative to the sun) |
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how long is the sidereal period? |
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27.3 days (how long it takes to orbit earth) |
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On a clear night when an observer in Los Angeles sees a first quarter Moon, an observer in London would see _____. |
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what is the lighter shadow the earth has called? |
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what is earth's darker shadow called? |
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if the entire moon enters the umbra we have a _____. |
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During a total eclipse, the Moon has a faint, red glow, why? |
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it's reflecting sunlight scattered in the Earth’s atmosphere. |
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what phase must the moon be in to have a total lunar eclipse? |
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would the sun be hidden behind the earth if you were standing on the moon during a total lunar eclipse? |
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true or false: the sun and moon have equal angular diameters? |
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what can be seen during a total solar eclipse? |
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the corona (chromosphere and prominence) |
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when the moon is closest to the earth |
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when the moon is furthest from the earth |
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what's another way of saying total solar eclipse? |
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when does an annular solar eclipse occur? |
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when the earth is at perihelion and the moon is at apogee |
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about how long is the saros cycle? |
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In early astronomy, it was almost universally believed that ____________. |
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the earth was at the center of the universe (geocentric) |
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What are some clues of ancient astronomy? |
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Stonehenge, the Mayans, the Anasazi, etc. |
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If the Earth's tilt were 13.5 degrees instead of 23.5 degrees, the path of the Sun would be |
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Not as far north in summer nor as far south in winter. |
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Just as the Sun sets, the shadows are: |
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Always the same length BUT pointed to a different compass point according to the season. |
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how many degrees does the moon's position change from one day to the next? |
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TRUE OR FALSE The full moon is never visible at noon. |
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The amount of time between two solar eclipses visible from the same location is about |
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Imagine that Earth did not turn on its axis. What would be true about the ecliptic? |
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It would still be defined and could be seen from all points on Earth, but only when they faced the sun |
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Imagine the earth did not turn on its axis what else would be true? |
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The day would be the same length as the year. |
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In one cycle of lunar phases, each crescent and gibbous phase has a duration of about how long? |
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If you could see the sun and stars during the daytime for several weeks, you would notice that the sun is doing what? |
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moving slowly eastward relative to the stars |
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About how many days must elapse between first-quarter moon and third-quarter moon? |
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TRUE OR FALSE During a solar eclipse, the moon casts a shadow on Earth. |
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The sun is about ____ times the diameter of Earth. |
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Earth is about ____times the diameter of the moon |
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What types of distances are typically listed in astronomical units (AU)? |
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distances in the solar system |
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A total solar eclipse occurs when the moon is...? |
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new and near the ecliptic |
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If the moon is at one of its nodes, it must be...? |
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Where is the sun in the winter? |
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a larger circle in Ptolemy's theory |
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a small circle in Ptolemy's theory |
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the planets' speeds vary because the circle is slightly off center in Ptolemy's theory |
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