How to Observe the Phases of the Moon

The phases of the moon have been observed and recorded by cultures throughout the world for thousands of years. The prominence of the moon in the sky as the second brightest object (after the sun) permits easy observation with the naked eye. The phases of the moon are divided into new moon, waxing, full moon and waning. The division between the light side and dark side of the moon is called the terminator. These phases are the result of the changing sun-earth-moon angle as the moon revolves around the earth.

Things You'll Need

• Pencil
• Log book

Instructions

1. Create a log to record observations. The log should have space to record the date and time of the observation, an empty circle representing the moon, and room to record any notes.

2. Each day/night, observe the moon. Record the date and time of the observation in the log. Shade in the moon diagram to match the phase observed.

3. Repeat the observations daily/nightly until one full cycle has been completed (about 28 days). If weather prevents observation, note it in your log for that day.

Tips & Warnings

• The moon is not in the same position in the sky at the same time each day. Altering the timing of observations will ensure the moon is visible (weather permitting) when the observations are made.

References

• Observing the Moon

Resources

• Phases of the Moon