ASTR 129 Introductory Astronomy I

Recommended Activity #5

 

Name: ____________________________

 

Use words, sketches, and/or diagrams to answer the questions below. Make sure you know how figure out the answer to any question like this about the phase of the Moon and how it’s linked to the time of day; don’t just memorize all the possibilities. Figure 3.2 might be helpful in answering these questions.

 

  1. If you see the Moon rising (in the east) at about the same time as the Sun sets in the west, what is the PHASE of the Moon?

    2. FULL MOON rises at sunset and sets at sunrise (it is 180 degrees away from the Sun in our sky).

  2. If you see the Moon while you are walking into Astronomy class in the late afternoon, (a) could it be a FULL Moon? (b) Could it be a NEW Moon? (c) Could it be First Quarter? (d) Could it be Third Quarter? For each question, explain why or why not.

    3. (a) NO - full moon doesn't rise until about sunset
    (b) YES and NO. The new moon would be "up". However, since we would be looking at the shaded side of the moon against the bright daytime sky, you would not be able to see the new moon.
    (c) YES - The first quarter moon rises at noon and sets at midnight, so it would be prominent high in the southeastern sky while you are walking into class.
    (d) NO - third quarter moon sets at noon, so you wouldn't be able to see it in the late afternoon.

  3. If you saw the Moon setting (in the west) while you are walking into astronomy class in the late afternoon, which PHASE would it be?

    4. The moon would be just a little bit west of the sun, so it would be a waning crescent phase. It would be kind of hard to see in the daytime unless you were looking for it.

  4. What time does the First Quarter Moon rise? What time does it set?

    5. rises at noon and sets at midnight (it is 90 degrees away from the sun)

  5. If you see the Moon low in the western sky an hour or two after the Sun sets, what is the PHASE of the Moon?

    6. It would be the waxing crescent phase, which is often the most beautiful phase of the moon. Since it is east of the sun, you can see it low in the west after sunset, while there's still a little bit of glow in the sky. It looks just like our state flag!

  6. When you look at the First Quarter Moon, which half is lit up, the right half or the left half? Which direction is that, North, South, East, or West?

    While facing the first quarter moon, you will see it's right half lit up. This is the western half (the "terminator" line between day and night runs roughly north-south). This is useful for finding directions when it's too cloudy or bright to see the north star or make out familiar constellations.