Lesson 2 Flashcards
Which of the following best describes the modern definition of a constellation?
a region of the celestial sphere
Which of the following statements about the celestial equator is true at all latitudes?
It represents an extension of Earth’s equator onto the celestial sphere.
Which of the following correctly describes the meridian in your sky?
a half-circle extending from your horizon due north, through your zenith, to your horizon due south
If it is midnight in New York, it is
daytime in Sydney, Australia.
By locating the north celestial pole (NCP) in the sky, how can you determine your latitude?
The altitude of the NCP is the same as your latitude.
Why do we have seasons on Earth
As Earth goes around the Sun and Earth’s axis remains pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight.
When someone on Earth observes the Moon in the first-quarter phase, someone on the Moon facing Earth observes Earth in the
third-quarter Earth phase
If the Moon is setting at 6 A.M., the phase of the Moon must be
full
If the Moon is setting at noon, the phase of the Moon must be
third quarter
If the Moon is rising at midnight, the phase of the Moon must be
third quarter.
At approximately what time would a full Moon be on your meridian
midnight
In which direction does a quarter Moon rise?
east
Ashen light (or earthshine) is
sunlight reflected by Earth that illuminates the “dark” portion of the Moon.
All of the following statements are true. Which one explains the reason why there is not a solar eclipse at every new Moon?
The orbital plane of the Moon is tilted by about 5° to the ecliptic plane.
What conditions are required for a solar eclipse?
The phase of the Moon must be new, and the nodes of the Moon’s orbit must be nearly aligned with Earth and the Sun.
What conditions are required for a lunar eclipse?
The phase of the Moon must be full, and the nodes of the Moon’s orbit must be nearly aligned with Earth and the Sun.
In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse?
The Moon’s umbra must touch the area where you are located
If the Moon is relatively far from Earth, so that the umbra does not reach Earth, someone directly behind the umbra will see
an annular eclipse
What happens during the apparent retrograde motion of a planet?
The planet appears to move westward with respect to the stars over a period of many nights.
The point directly over your head is called
the zenith
An angle of 1 arcsecond is
less than the thickness of a human hair held at arm’s length
Suppose you use the Southern Cross to determine that the south celestial pole appears 40 degrees above your horizon. Then you must be located at
latitude 40 degrees south.
Suppose you are facing north and you see the Big Dipper close to your northern horizon, with Polaris (and the Little Dipper) above it. Where will you see the Big Dipper in six hours?
to the right of Polaris; that is, 90 degrees counterclockwise from its current position
It’s 6 A.M. and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon’s phase?
third quarter
