The sky, moon phases, eclipses Flashcards
What is astronomical unit?
Average distance from earth to sun
1.5 x 10*8 km = 1 AU
What is light year?
It is a unit of distance, how far light can travel in one year
1 light year = 63240 AU
What is diurnal motion?
The daily motion of stars and other celestial objects due to the earth’s rotation around its axis from west to east
Terrestrial coordinates
Latitude: vĩ tuyến
Longtitude: Kinh tuyến
Celestial reference point
Right ascension: xích kinh east-west
Declination: xích vĩ north-south
What is Precession?
It is a change in the orientation of the rotational axis of a rotating body.
What are seasonal variations?
Changes in temperature and daylength
List the northern hemisphere special dates
Vernal Equinox (March 21) Autumnal Equinox (Sept 21) day=night, due E, due W Summer Solstice (June 21) day>night, NE, NW Winter Solstice (Dec 21) day
What is the Analemma?
It is the changing position of the Sun at the same time of day on different days of the year
List the phases of the moon
A: New moon B Waxing crescent C: First quarter D: Waxing gibbous E: Full moon F: Waning gibbous G: Third quarter H: Waning crescent Waxing: crescent moon early in the evening Waning: crescent moon early in the morning
How do you tell whether the Moon is waxing or waning?
When the Moon trails the Sun in the sky (is East of it) we have a waxing phase
When the Moon is ahead of the Sun in the sky (is West of it) we have a waning phase
What is Lunar Eclipses?
Moon passes into the Earth’s shadow at Full Moon
S-E-M
Total, partial & penumbra
What is Solar Eclipses?
Earth passes into the Moon’s shadow at New Moon
S-M-E
Total, partial, annular
What is total lunar eclipse?
“Blood moon”, full moon passes into the umbra of Earth’s shadow
What is partial lunar eclipse?
Moon is only partially engulfed in the Earth’s umbra
