Term
| what is the imaginary sphere that is centered on Earth and on which all the stars are observed on called? |
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Definition
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Term
| What is the Celestial Equator a projection of? |
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Definition
| the Earth's equator onto the celestial sphere |
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Term
| what is the most common coordinate system used in astronomy? |
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Definition
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Term
| In what units is Declination measured? |
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Definition
| in degrees (runs from 0 degrees to 90 degrees) |
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Term
| What units is Right Ascension measured in? |
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Definition
| in hours and ranges from 0 to 24 hours |
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Term
| Originally, what did "constellation" mean? |
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Definition
| loose groups of stars that indicated a specific picture or figure in the sky |
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Term
| What does "constellation" mean to modern astronomers? |
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Definition
| not just a figure, but an area in the sky |
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Term
| How many constellations are there? |
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Definition
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Term
| How do modern astronomers name stars? |
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Definition
| greek letters to indicate brightness |
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Term
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Definition
| the position directly above the observer |
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Term
| Why can't we see the stars during the day? |
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Definition
| because the sun is too bright, but the stars are always there |
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Term
| How do you center objects in a field of view with the Sky6 Software? |
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Definition
| place the cursor on the object and right click on the mouse. When the pop up menu appears, click "center". |
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Term
| How do you obtain info about an object with the Sky6 Software? |
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Definition
| place cursor on object and left click on the mouse. A new window with all info will pop up |
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Term
| What icons activate the equatorial and horizon reference lines with the Sky6 Software? |
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Definition
| the red globe (horizon) and the blue globe (equatorial) |
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Term
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Definition
| a particular group of stars that form simple images but are not constellations |
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Term
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Definition
| a change in direction of the axis of a rotating object |
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Term
| how long does it take for the earth's axis to precess? |
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Definition
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Term
| What star does the Earth's axis currently point too? |
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Definition
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Term
| Where will the Earth's Axis point in 13,000 years? |
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Definition
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Term
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Definition
| the apparent path that the sun makes in the sky |
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Term
| How long is the moon's cycle of phases? How long is the moon's complete cycle? |
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Definition
| each phase lasts approx. 3 to 4 days. The moon's complete cycle is approx. 29.5 days |
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Term
| What two things must occur for a lunar eclipse? |
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Definition
1. it must be a full moon
2. Moon crosses ecliptic |
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Term
| What are the names of the two parts of the Earth's shadow? |
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Definition
| the penumbra and the umbra |
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Term
| What is a saros and how long is it? |
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Definition
| a saros is a period of time that's passed before the same eclispes repeat themselves. It is 18 years, 11 days and 8 hours |
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Term
| What is the wavy line of the constellation chart? |
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Definition
| the ecplictic. it's the path of the sun |
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Term
| What is the celestial equator known as? |
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Definition
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Term
| What is the terrestrial system? what is it based on? |
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Definition
| a system used for Navigation on Earth; its based on LATITUDE and LONGITUDE |
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Term
| What are lines of latitude used to measure? Which way do they run? |
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Definition
| used to measure NORTH and SOUTH and they run EAST and WEST |
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Term
| Where is the Greenwich Meridan located? |
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Definition
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Term
| What is longitude used to measure? Which way does it run? |
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Definition
| used to measure EAST and WEST. Runs NORTH and SOUTH |
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Term
| How long does it take the Earth to rotate once it's axis? |
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Definition
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Term
| What is the Horizon system? What is it defined bY? |
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Definition
| it's local to the observer; doesn't involve geographical coordinates and is defined by AZIMUTH and ALTITUDE |
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Term
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Definition
| measured eastward, begins in the northern direction from 0* to 360* around in a circle where observer is standiing |
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Term
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Definition
| measured from 0* to 90*; it is + toward the zenith and - toward the nadir |
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Term
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Definition
| the position opposite to the zenith |
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Term
| What is the Equatorial System? |
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Definition
| uses RA and Declination; it is a coordinate system that refers to fixed points in the sky and Earth moves thru them |
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Term
| Which direction does RA increase? |
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Definition
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Term
| What is the International Date Line? |
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Definition
| runs approx. on the 180* of longitude; if crossed traveling WEST to EAST, date is decreased by one day. If crossed traveling EAST TO WEST, it's increased by one day |
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Term
| Coverting from UT to PST, what is the formula? |
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Definition
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Term
| Converting from PST to UT, what is the formula? |
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Definition
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Term
| The brightest star is designed what Greek letter? the second brightest? the third and fourth? |
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Definition
FIRST: Alpha
SECOND: Beta
THIRD: Gamma
FOURTH: Delta |
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Term
| When is the best time to observe a star? |
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Definition
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Term
| if a star is never in the zenith, when would be the best time to view it? |
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Definition
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Term
| what is the fraction of illumination? |
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Definition
| the fraction of the moon that we see from Earth |
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Term
| What are the four phases of the moon? |
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Definition
| The New Moon, the First Quarter, Full Moon, and Last Quarter |
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Term
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Definition
| approx. fifty minutes later each night |
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Term
| What is the apogee? Perigee? |
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Definition
| APOGEE: the moon is furthest from the earth PERIGEE: the moon is closest to the earth |
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Term
| The moon orbits the Earth at what tilt degree? |
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Definition
| 5.2* in respect to ecplictic |
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Term
| what is the eclispe season? |
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Definition
| the days before or right after the moon crosses the ecliptic |
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Term
| what are Inferior planets? |
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Definition
| the planets closer to the sun than the Earth |
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Term
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Definition
| when Mercury and Venus pass between the Earth and the Sun |
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Term
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Definition
| when the superior planets move against stars from west to east |
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Term
| what is retrograde moition? |
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Definition
| superior planets moving against stars East to west |
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Term
| what is retrograde motion a result of? |
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Definition
| the faster earth passing the slower planet at opposition |
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