Chapter 2 Flashcards
Declination is a measure of a star’s location relative to the
celestial equator.
Right ascension is a measure of a star’s location on the celestial sphere that is most similar to which measurement of location on Earth?
longitude
Your meridian is an imaginary arc on the sky that connects the
zenith and the north and south directions.
No matter where you are on Earth, stars appear to rotate about a point called the
celestial pole.
Circumpolar stars are stars that are
always above the horizon.
If the star Polaris has an altitude of 50°, then we know that our position on Earth is
latitude +50°.
At a latitude of +15°, how far above the horizon is the north celestial pole located?
15°
At which latitude is the north celestial pole located at your zenith?
+90°
At which latitude is the north celestial pole at your horizon?
0°
If you go out at exactly 9 P.M. each evening over the course of 1 month, the position of a given star will move westward by around 30 degrees. What causes this motion?
the revolution of Earth around the Sun
For an observer in the Northern hemisphere, on which day of the year does the Sun reach its southernmost point on the celestial sphere?
winter solstice
On a certain date, the constellation of Orion is centered on your meridian at midnight. Exactly 6 months later, Orion will be on your meridian at
noon.
which constellation of the zodiac would be nearest to the meridian at midnight in mid-November?
Taurus
which constellation of the zodiac would be nearest to the meridian at 6 P.M. in mid-March?
Aquarius
which time of the day or night will the zodiac constellation Taurus rise in May?
6 A.M.
Six months from now, at which time of day will the stars be in the same places in your sky as they will be at midnight tonight?
noon
Earth’s rotational axis precesses in space and completes one revolution every
26,000 years.
If Earth’s axis were tilted by 5° instead of its actual tilt, how would the seasons be different than they are currently?
Winters would be warmer.
If Earth’s axis were tilted by 30° instead of its actual tilt, how would the seasons be different than they are currently?
Winters would be colder.
We experience seasons because
Earth’s equator is tilted relative to the plane of the solar system.
During which season (in the Northern Hemisphere) could you see the Sun rising from the northernmost point on the horizon?
summer
The celestial sphere model places the stars
on the surface of a distant sphere that rotates around Earth.
At which of the following latitudes is it possible for the Sun’s rays to be perpendicularly incident on the ground at some point during the year?
20°
If tonight the Moon is in the waxing gibbous phase, in three days the phase of the Moon will be
full.
If there is a full Moon tonight, approximately how long from now will it be in the third-quarter phase?
1 week
The sidereal period of the Moon is closest to
27 days.
The Moon’s sidereal period is 2.2 days shorter than the period during which the Moon’s phases change because
Earth moves significantly in its orbit around the Sun during that time.
If a person on Earth views the Moon in a waxing-crescent phase, in which phase would Earth appear to a person on the Moon?
waning gibbous
which position must the Moon be located for a lunar eclipse to occur?
on the right side of the earth, by the shaded region
which position must the Moon be located for a solar eclipse to occur?
on the left side of the earth, facing the illuminated region
A partial lunar eclipse occurs when
the Moon passes through part of Earth’s shadow.
If you are lucky enough to see a total solar eclipse, you must be standing in the
Moon’s umbra, The darkest part of the Moon’s shadow
If you are observing a partial solar eclipse, you must be standing in the
Moon’s penumbra.
During which Moon phases can an eclipse (of any type) occur?
new and full
A type of eclipse in which the Sun appears as a bright ring is called a(n)
annular solar eclipse.
