The Moon is a slim 11% crescent on July 17
NASA’s Daily Moon Guide says the Moon is in its waxing crescent phase, with the next full Moon due on July 29.
By Poppy Nakagawa · Culture Writer
2 min read
The Moon is back on the night-sky comeback trail, but only just. On Friday, July 17, NASA’s Daily Moon Guide lists it as a waxing crescent, with 11% of the lunar surface visible from Earth.
That means skywatchers will see a thin bright slice rather than a showy lunar disc. The new lunar cycle is in its third day, so the Moon is beginning to show itself again and should become easier to spot over the next few nights.
Do not expect a detailed lunar sightseeing session just yet. With so little of the Moon lit, binoculars or telescopes will not reveal craters, mountains or other surface features tonight, according to the guidance.
When the full Moon arrives
The next full Moon is scheduled for July 29. That is when the whole face of the Moon visible from Earth will be illuminated.
Until then, the lit portion will continue to grow through the waxing crescent stage, then move toward the first quarter and waxing gibbous phases before reaching full brightness.
Why the Moon keeps changing shape
NASA explains that the Moon takes about 29.5 days to complete one orbit around Earth. During that trip, it passes through eight main phases.
The same side of the Moon faces Earth throughout the cycle. What changes is how much sunlight is reflected from the lunar surface toward us as the Moon moves around the planet.
That shifting sunlight is why the Moon appears to grow from a faint crescent into a half-lit Moon, then a full Moon, before shrinking back down and beginning the cycle again.
The eight Moon phases
New Moon: The Moon sits between Earth and the sun, leaving the side facing Earth dark and not visible to the eye.
Waxing Crescent: A narrow strip of light appears on the right side in the Northern Hemisphere.
First Quarter: The right half is illuminated, creating the familiar half-Moon look.
Waxing Gibbous: More than half of the Moon is bright, but it has not reached full Moon yet.
Full Moon: The visible face is fully lit.
Waning Gibbous: The Moon begins losing light on the right side in the Northern Hemisphere.
Third Quarter, also called Last Quarter: The Moon looks half-lit again, this time with the left side illuminated.
Waning Crescent: A final slim glow remains on the left side before the Moon goes dark again.
This story draws on original reporting from Mashable.