Moon phase on September 20, 1989

Waning Gibbous, 69%
🌖 Waning Gibbous
Wednesday, September 20, 1989 · at noon (Brasília)
Illumination: 69% Age: 20.4 days Cycle: 69%

On Wednesday, September 20, 1989 the Moon was in its waning gibbous phase, with 69% of its disk illuminated and an age of 20.4 days since the last new moon. The lit part starts to shrink. The Moon rises a few hours after dusk and is still in the sky when day breaks.

Moon data for this date

Moon at noon Brasília time (UTC-3)
Phase🌖 Waning Gibbous
Illumination69%
Moon age20.4 days
Day of the weekWednesday
Last new moonAugust 31, 1989 at 02:45
Next full moonOctober 14, 1989 at 17:32 (in 24.2 days)
Next new moonSeptember 29, 1989 at 18:47 (in 9.3 days)

The Moon on the surrounding days

Compare the phase and illumination over the three days before and after. Click a day to open its page.

← September 19, 1989 September 21, 1989 →

About the waning gibbous

The lit part starts to shrink. The Moon rises a few hours after dusk and is still in the sky when day breaks. The phase name comes from the Moon's position in its 29.53-day cycle: on September 20, 1989 it had completed 69% of the cycle that began with the new moon on August 31, 1989.

Looking for another date, such as a birthday? Use the Moon phase on the day I was born tool, see the Moon phase today page with the lunar calendar, or find the day of the week of September 20, 1989. For sun times, check sunrise and sunset.

Frequently asked questions

What is the Moon phase on September 20, 1989?

On September 20, 1989 the Moon was in its waning gibbous phase, with 69% of the disk lit (calculated at noon Brasília time).

How old is the Moon on that date?

The age is the time since the last new moon: 20.4 days of an average 29.53-day cycle.

When is the next full moon after that date?

The next full moon after September 20, 1989 falls on October 14, 1989 at 17:32 Brasília time.

When is the next new moon after that date?

The next new moon after September 20, 1989 falls on September 29, 1989 at 18:47 Brasília time.

How is the Moon phase calculated?

With Jean Meeus's astronomical formulas for the instants of new, quarter and full moon. The age comes from the time since the last new moon and the illumination is (1 − cos(2π × cycle fraction)) / 2.

Is the phase the same everywhere in the world?

Yes, the phase and the illuminated percentage are the same across the planet at any given instant. Only the orientation changes: in the southern hemisphere a waxing Moon is lit on the left, in the northern one on the right.