P7 Page 3

Question 0

What are the two angles used to measure the positions of the sky?

Answer 0

Declination- Celestial latitude, measured on degrees.

Right ascension- Celestial longitude,measured in degrees or time.

Question 1

To measure stars, what two fixed positions do astronomers use?

Answer 1

The pole star- A star that doesn’t seem to move because it is directly above the North Pole( and spin axis) of Earth.

The celestial equator- An imagery plain running across the sky, extending from the Earth’s equator.

Question 2

The closer to the Sun, the faster or slower the planet orbiting?

Answer 2

Faster

Question 3

What is the retrograde motion?

Answer 3

When a planet seems to change direction and go the other way for a bit , making a loop or a squiggle in its track before carrying on normal.

Question 4

Why does the retrograde motion occur?

Answer 4

I happens because both the planet and Earth are moving around the sun- So were are seeing the motion of the star relative to Earth.