02 Naked Eye Observations Study Set
The faintest star that can be seen by the naked human eye (with normal vision) is much brighter than the faintest stars seen by the Hubble space telescope. To approximately what order of magnitude is this true? (How much brighter is the star we can see?
10,000,000,000 times brighter
How long as stars in the sky at mid northern latitudes?
12 hours for those that rise directly east and set directly west. More for stars that rise in the north and less for those that rise in the south.
The first catalogue of stars was created by Hipparchus, who categorized the stars by brightness in a system of magnitudes, how many magnitudes were there to begin with?
6
In modern times, like state boundaries on a map, the sky is separated into __ carefully delineated areas defined by the _________ located within its boundaries.
88; constellation
What is a constellation?
A pattern of stars forming fan abstract image in a region of the sky including all stars within that region
What is the celestial sphere?
A useful mental model for understanding how the stars move through the sky.
How might stars in the Southern hemisphere appear to an observer standing on an isolated hill in North America?
An observer in North America would not be able to see many of the stars in the Southern hemisphere.
Many of the brightest stars are known by a proper name given to them by early astronomers. In what language are most of these names as they are known today?
Arabic
If the star directly above you stays fixed all night and the stars do not rise or set, where are you?
At one of the poles
What causes the stars to move in circles across the night sky over the course of a night?
Because the Earth is constantly rotating the stars appear to rotate around it in the opposite direction.
Which planets (other than Earth) can be seen using only the naked eye?
Mercury, Venus, Mars, Jupiter, and Saturn.
If all of the stars rise straight up, cross the sky directly from west to east, and are in the sky for exactly 12 hours, where are you?
On the equator
Star A has a magnitude of 2 while Star B has a magnitude of 5. Which star is brighter?
Star A
Why do stars appear to twinkle when we look at them from Earth?
The air in Earth's atmosphere is unstable and changes the direction of the light that passes through it several times per second. As a result, we on the surface see changes in brightness that we call twinkling.
Why is it that some stars appear to have color while other simply appear to be white?
The color receptors in our eyes are not sensitive enough to detect color in fainter stars and as a result only the brightest stars in the sky appear to have color.
Why do some stars appear brighter than others as seen from the same spot on Earth?
The inherent brightness of each individual star differs.
Why do the planets not appear to twinkle like stars do?
They are closer to Earth and as a result appear larger, meaning their light is not as distorted as it passes through the atmosphere.
Light pollution has negative effects not only on stargazing but also on the behaviors of certain bugs and other animals. What action is necessary to decrease light pollution in a city?
Use a different type of lighting that directs light towards the ground.
How many naked eye stars are there?
a few thousand
