Elementary Astronomy Ch. 1 – Flashcards
Unlock all answers in this set
Unlock answersquestion
Aster
answer
Star
question
Nomie
answer
Naming, Organization
question
How many "stars" can the naked eye see on a clear night?
answer
~6000
question
Do stars change relative position to each other?
answer
No
question
What direction do the stars seem to travel from the equator?
answer
Perpendicular to horizon
question
Constellation
answer
Regions of sky, familiar patterns
question
What do constellations help do?
answer
Locate specific celestial bodies.
question
How many constellations do astronomers recognize?
answer
88
question
Winter Triangle
answer
Procyon, Sirius, Betelgeuse
question
Summer Triangle
answer
Vega, Deneb, Altair
question
Celestial Sphere
answer
A way to describe the universe surrounding Earth
question
Where are the Celestial Poles
answer
Directly above Earth's poles
question
Celestial Equator
answer
Divides Celestial sphere into two hemispheres
question
Right Ascension
answer
Longitude on Celestial Sphere
question
Right Declination
answer
Latitude on Celestial Sphere
question
Altitude-Azimuth Coordinate System
answer
Coordinate system thats universal. Altitude is the angle straight up from horizon, Azimuth is angle eastward from north along horizon.
question
Ecliptic
answer
Annual path of sun on celestial sphere. Annual path of Earth around sun.
question
What is the angle of deviance from perpendicular of Earth's axis from the ecliptic?
answer
23.5 degrees
question
What two measurements do we need to locate a "star"?
answer
Direction and Angular separation from some reference point
question
Rotation
answer
Earth's rotation around its own axis, causes day and night
question
Revolution
answer
Earth's orbit around the sun, causes seasons and years
question
Precesses
answer
Earth's axis forming a cone rotation over course of 26000 years
question
Moon's orbit causes...
answer
lunar phases, cycle of tides, eclipses
question
What causes seasonal changes?
answer
The tilt of Earth's axis
question
Summer Solstice
answer
Point of sun's path farthest north on ecliptic. June 21st
question
Winter Solstice
answer
Point of sun's path farthest south on ecliptic. December 22th
question
Vernal Equinox
answer
Sun crosses celestial equator while sun is moving north. March 20th
question
Autumnal Equinox
answer
Sun crosses celestial equator while sun is moving south. September 22nd
question
Day and night are of equal length
answer
Equinox
question
Longest day of the year
answer
Summer Solstice
question
Shortest day of the year
answer
Winter Solstice
question
Seasonal names of the solstices and equinoxes refer to which hemisphere?
answer
Northern. Southern hemisphere's seasons are exactly opposite.
question
Sidereal Days
answer
4 min. shorter than solar day. Measured in respect to stars fixed on celestial sphere.
question
Solar Days
answer
Measured in respect to the rotation of the Earth around its own axis.
question
Terminator
answer
Boundary between bright and dark regions of the moon.
question
Synodic period
answer
Phase cycle of the moon. 29 1/2 days long.
question
Sidereal Months
answer
Time it takes the Moon to complete one revolution with respect to background stars. About 27.3 days.
question
Synodic Months
answer
Time between consecutive new moons/ full moons. 29.5 days.
question
What moon phases can eclipses occur?
answer
New/ Full moon
question
Eclipse
answer
Moon, Sun, and Earth are aligned. Moon can be shadowed by Earth (Lunar Eclipse). Moon casts a shadow on Earth (solar eclipse).
question
Why doesn't an eclipse occur during every full/ new moon?
answer
Moon's orbit is tilted 5 degrees from ecliptic plane.
question
Penumbral Lunar Eclipse
answer
Moon appears dim
question
Partial Lunar Eclipse
answer
Part of the Moon enters the umbra of Earth's shadow and darkens
question
Total Lunar Eclipse
answer
All of Moon enters earth's shadow and becomes reddish. Lit by light bending around Earth's atmosphere.
question
Total Solar Eclipse
answer
Entirety of sun is covered by Moon.
question
Annular Eclipse of sun
answer
Moon is too far from earth to cover all of sun, so a ring of sun appears around moon.
