Moon and eclipses

Understand the phases and apparent size of the moon, view the moon's position, lunar orientation, and calculation of solar and lunar eclipses.

First look at the phases of the moon and the size of the sun and moon, and then go into positions, periodic events and eclipses.

Let’s look at the phenomena in life first →

• Why does part of the Moon seem to disappear?

  We stay on the earth and watch how the bright side of the moon turns towards us little by little as it orbits.

• Does the moment of the full moon come every same number of days?

  The moon phase chart tells us how the moon phase needs real period correction.

• The sun is so big, why does it look about the same size as the moon?

  The size of the disk in front of you depends on how big the object is and how far it is from you.

• The moon moves every day, how to calculate its direction and distance at the moment?

  Change the day so that the Moon's position is actually recalculated from the original book's periodic terms.

• The moon always faces us with the same side, so why can we see more edges?

  Let the lunar surface grid follow the changes of the real balance, distinguishing the viewing geometry from the moon's own swing.

• When does a crater on the moon get the sun?

  Move the sunrise problem on the earth to the moon and use the direct point of the sun to find the boundary between light and dark.

• The moon sometimes looks bigger. Is it closer to us?

  First calculate the perigee and apogee times, and then compare the corresponding distances.

• When the moon crosses the ecliptic plane, will a solar or lunar eclipse definitely occur?

  First calculate the moment when it crosses the orbital reference plane, and then distinguish its relationship with the moon phase.

• The moon sometimes goes very high. Can it be the same height every month?

  First calculate how far north or south the moon can go, and then consider where you stand.

• The moon passes in the direction of the sun every month, so why isn't there a solar eclipse every month?

  Look to see if the moon's shadow touches the earth, instead of just looking at "whether it's a new moon today."

• Why do lunar eclipses sometimes only dim and sometimes missing a large chunk?

  Let the moon actually walk through the penumbra and umbra to see which boundary is touched.