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45 Cards in this Set

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How many stars are visible at any time from Earth?
3000
A grouping of stars creating an image.
ASTERISM
A region of the sky often containing one major image.
CONSTELLATION
The current north star.
POLARIS
The "map" of the night sky.
CELESTIAL SPHERE
Degrees north or south of the celestial equator.
DECLINATION
Similar to longitude on Earth.
RIGHT ASCENSION
Hours/minutes/seconds east of the Sun's position at spring equinox.
RIGHT ASCENSION.
Similar to latitude on Earth.
DECLINATION
The daily motion of Earth, from noon to noon.
DIURNAL
The length of time for Earth's daily motion, from noon to noon.
SOLAR DAY
Marked by the highest position of the Sun during the day.
SOLAR NOON
Causes day and night.
ROTATION
Length of one revolution.
365.25 days
Length of one rotation.
24 hours
Plane of Earth's path around Sun.
ECLIPTIC
The closest point of an orbit to the central object.
PERIHELION
The furthest point of an orbit to the central object.
APHELION
Causes the seasons.
1) TILT OF EARTH ON ITS AXIS
2) POSITION IN ORBIT
A day with approximately equal periods of light and dark.
EQUINOX
The day with the least amount of daylight.
WINTER SOLSTICE
The day with the most amount of daylight.
SUMMER SOLSTICE
The 12 constellations through which the Sun appears to move.
ZODIAC
The day where the Sun reaches the northernmost point.
SUMMER SOLSTICE
The day where the Sun reaches the southernmost point
WINTER SOLSTICE
The day where the Earth's orbit crosses the celestial equator.
EQUINOX
Time from one vernal equinox to another.
TROPICAL YEAR
A rotation or wobble of Earth's axis.
PRECESSION
Why is Polaris eventually no longer going to be the north star?
PRECESSION
Time for Earth to orbit once around Sun relative to fixed stars.
SIDEREAL YEAR
A year based on constellations.
SIDEREAL
A year based on seasons.
TROPICAL
Number of timezones on Earth.
24
Reason for timezones on Earth.
24 hours in rotation.
One complete lunar cycle.
LUNAR MONTH
Number of days in a lunar cycle.
29.5
Number of days in one rotation of the Moon.
29.5
Number of days in one revolution of the Moon
29.5
Time of year Earth is closest to the Sun.
JANUARY
Reason for leap year.
EXTRA 0.25 days/year
Another name for a lunar month.
SYNODIC MONTH
Period of time of Moon's position to complete one cycle compared to stars.
SIDREAL MONTH (27.3 days)
Why solar day is unequal to sidereal day
EARTH'S REVOLUTION
Why synodic moth is unequal to sidereal month
EARTH'S REVOLUTION
Why tropical year is unequal to sidereal year
PRECESSION