Astronomy chapter 2
If we have a new moon today, when we will have the next full moon?
.2 weeks
The angular size of your finger at arm's length is about 1°. How many arcseconds is this?
60 x 60 = 3600 arc seconds
We cannot see a new moon in our sky because _________.
A new moon is quite near the sun in the sky
Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called _________.
Circumpolar
Longitude
Distance east or west of the prime meridian, measured in degrees
True or False? Earth is closer to the sun in summer and farther from the sun in winter?
False
Angular measurements
Full circle = 360 degrees 1 degree = 60' (arcminutes) 1' = 60" (arcseconds)
Meridian
Line passing through zenith and connecting N and S points on the horizon
Why do we see phases of the moon?
Lunar phases are a consequence of the Moon's 27.3-day orbit around Earth.
Waxing
Moon visible in afternoon-evening Gets "fuller" and rises later each day
Waning
Moon visible in late night/morning Gets "less" and sets later each day
phases of the moon
New Waxing crescent First quarter Waxing gibbous Full Waning gibbous Third quarter Waning crescent
During the time that a planet is in its period of apparent retrograde motion: _________
Over many days or weeks the planet moves westward relative to the stars rather than usual eastward relative to the stars
Latitude
Position north or south of equator
Which rise in the east and set in the west?
Stars Sun Moon Galaxies
Equinoxes
Sun rises precisely due east and sets precisely due west
If you are located in the Northern Hemisphere, which of the following correctly describes a relationship between the sky and your location?
The altitude of the North celestial pole equals your latitude
How would a star's parallax change as its distance from Earth increases?
The parallax shift decreases as the stars distance from Earth increases
Why do we have seasons on Earth?
The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.
How does the orientation of Earth's axis change with time?
The tilt remains about 23.5 degrees (so the seasons pattern is not affected), but Earth has a 26,000-year precession cycle that slowly and subtly changes the orientation of the Earth's axis
It's 9am you look up in the sky and see a moon with half its face bright and half dark. What phase is it?
Third quarter
The North Star (Polaris) is 50° above your horizon, due north. Where are you?
You are latitude 50 degrees N
Horizon
altitude = 0 degrees all points 90 degrees away from zenith
Zenith
altitude = 90 degrees the point directly overhead
Which is NOT using the term "angular size/angular distance" correctly?
angular distance between those two bright stars in the sky is about 2 meters
Lunar eclipses can occur only during a _________.
full moon
Summer solstice
highest path, rise and set at most extreme north of due east
Winter Solstice
lowest path, rise and set at most extreme south of due east
The brightest stars in a constellation
may actually be quite far away from each other
total lunar eclipse
moon passes entirely through umbra
penumbral lunar eclipse
moon passes through penumbra
Solar eclipses can occur only at ________
new moon
partial lunar eclipse
part of the moon passes through the umbra
Solar eclipses can be ____________
partial, total, or annular
Lunar eclipses can be __________
penumbral, partial, or total
constellation
region in the sky as seen from earth
Ecliptic
the path the Sun appears to trace around the celestial sphere each year
