Chapter 2: Discovering the Universe for Yourself Flashcards
(41 cards)
What is a constellation?
A region of the sky with well defined borders.
What is the cellestial sphere?
The illusion of the stars appearing to be close to one another on a sphere that encompasses the earth.
What is the north celestial pole?
The point directly over the earth’s north pole.
What is the south celestial pole?
The point directly over the earth’s north pole.
What is the celestial equator?
A projection of earths equator into space, making a complete circle around the celestial sphere.
What is the ecliptic?
The path that the sun follows as it appears to circle around the celstial sphere.
What is the local sky?
The sky as seen from where you are standing.
At what angle does the ecliptic cross the celestial equator?
23.5 Degrees as that is the tilt of earth’s axis.
What is the zenith?
The point directly overhead of an observer.
What is the meridian?
An imaginary half circle stretching from the horizon die south, through the zenith, to the horizon due north.
What is an azimuth?
The direction of an object in the local sky that is measured in degrees clockwise from due north.
How many arcminutes are in a degree?
60’
How many arcseconds are in an arcminute?
60”
What makes a star circumpolar?
The star remains above the horizon all day.
What measurement is the altitude of the celestial pole in your sky equal to?
Your latitude on earth.
Why do we have seasons?
The tilt of earth’s axis results in more direct sunlight for longer periods of time during the summer and less direct sunlight for shorter periods of time during the winter.
What is precession?
The gradual wobble that alters the orientation of Earth’s axis in space.
How long is the lunar cycle?
29.5 days
If the moon is at it’s highest point at midnight, what phase is it in?
Full moon
If the moon is at it’s highest point before dawn, what phase is it in?
Waning Gibbous
If the moon is at it’s highest point at sunrise, what phase is it in?
Third quarter
If the moon is at it’s highest point at mid-morning, what phase is it in?
Waning Crescent
If the moon is at it’s highest point noon, what phase is it in?
New moon
If the moon is at it’s highest point at mid-afternoon, what phase is it in?
Waxing crescent
