Week 1 Flashcards
(20 cards)
T/F, on average the hottest day of the year is when the sun reaches the highest point in the sky?
False. Though the light is most direct at that time, the earth’s atmosphere holds in the heat gained. This means that the months following this date will be hotter (july and august)
T/F, A star rises in the southeastern sky, later it will rise in the north western sky?
False. The rotation and orbit of the earth wouldn’t allow it. Though the sun shifts places in the sky, it always rises in the east.
What is the astronomical name for the time in Greenwich England?
Universal Time.
Alaska has an altitude of 61.2 degrees north. Provo has an altitude of approximately 40 degrees north. Would Polaris be higher in the sky in Alaska, or Provo?
Alaska. Our latitude in the Northern Hemisphere is equivalent to the Altitude of Polaris.
A star rises at 12 o’clock midnight. When will it rise 10 days later?
40 minutes earlier. Stars rise an average of 4 minutes earlier per night.
On a given night, we see different stars at different times of the night. Six months later, we see a different set of stars. Explain why these two changes occur.
During the course of the night, stars shift position, set, and rise, due to the position of the earth. Six months later, you’ll see a new set of stars because the earth has rotated around the sun.
What are two factors that contribute to temperature, not including weather?
The tilt of the earth allows either the northern or southern hemisphere to have the most direct sunlight, which gives us alternating seasons.
The earth’s atmosphere can hold in heat, which greatly effects temperature.
If you read about the North Star in an ancient text such as the Old testament, would it be referring to our current Polaris?
No. Because of the wobble of the earth, or the procession of the equinox, the Star due north of the earth’s pole changes every thousand years or so.
Altitude
Measurement from the horizon northward, to the location in the sky.
Celestial Equator
The Earth’s projected equator onto the night sky (or celestial sphere).
Equinox
Where the celestial equator crosses the ecliptic.
Celestial Pole
Projection of the Earth’s poles onto the celestial sphere.
Declination
Angular measure north or south of the celestial equator.
Right Ascention
Measurement of a star’s position along the celestial equator beginning at the vernal equinox. Measured in units of time.
Right Ascention and Declination are measurements that will not change over time like altitude and azimuth.
Right ascention/Azimuth - horizontal
Declination/altitude - Vertical
Meridian
A line going from pole to pole crossing through the zenith.
Diurnal Motion
Nightly movement of the stars.
Solstice
When the sun reaches it’s highest or lowest point in the sky.
Ecliptic
The path of the sun in the sky.
Zenith
The point in the sky directly overhead.
Azimuth
Measurement from north to east. Altitude and Azimuth are used to locate objects in the night sky in relation to your immediate location. Once the stars move, their altitude and azimuth changes.
