How to Observe Moon Phases and Full Moons: A Practical Guide

What Causes the Moon's Phases

The Moon does not produce its own light. The Sun always illuminates one half of it, and as the Moon orbits Earth, the portion of that sunlit half visible from Earth changes, according to NASA's Science division. This produces the familiar sequence of phases over what the U.S. Naval Observatory (USNO) calls a lunation, averaging about 29.5 days.

USNO defines the four primary phases mathematically, based on the difference between the Moon's and the Sun's position in the sky: the gap is 0 degrees at new moon, 90 degrees at first quarter, 180 degrees at full moon, and 270 degrees at last quarter.

The Eight Phases, Explained

• New Moon — the sunlit side faces away from Earth, so the Moon is effectively invisible (0% illuminated, per USNO).
• Waxing Crescent — a thin sliver becomes visible as the dayside starts to come into view (NASA).
• First Quarter — half the disc is lit (50% illuminated, USNO); the Moon stands high in the evening sky.
• Waxing Gibbous — most of the dayside is visible and the Moon appears noticeably brighter (NASA).
• Full Moon — the entire near side is lit (100% illuminated, USNO), opposite the Sun as seen from Earth.
• Waning Gibbous — the lit portion starts shrinking again after full moon (NASA).
• Last (Third) Quarter — again half-lit, declining toward new moon (USNO).
• Waning Crescent — a thin curve remains before the cycle returns to new moon (NASA).

Step-by-Step: How to Watch the Moon

1. Check a moon-phase calendar or app for the current phase and that night's moonrise and moonset times.
2. Pick a phase other than full moon if your goal is to see craters and mountains: NASA's viewing guide notes that shadows along the terminator (the line between light and dark) make surface features far more visible than at full moon.
3. Start with the naked eye. Under clear, dark conditions you can pick out large impact craters such as Copernicus, Tycho and Aristarchus, NASA says.
4. Add binoculars with at least 7x magnification to resolve craters and major mountain ridges; above 10-15x magnification, a tripod helps keep the image steady, according to NASA.
5. Use a telescope for finer detail — crater chains and other surface features become visible, NASA notes.
6. Observe on different nights across the month. Because of libration, the Moon's slight wobble in its orbit, experienced observers can eventually see roughly 59% of the lunar surface, per NASA.
7. Keep a simple log of date, phase and visible features to track how the view changes over the roughly 29.5-day cycle.

Named Full Moons and the 2026 Calendar

Many cultures gave individual full moons their own names, a tradition that today mostly draws on Native American and European almanac calendars, according to the Royal Observatory Greenwich (RMG). RMG publishes exact full-moon times for London each year.

The Hunter's Moon is not tied to a fixed calendar month. WEB.DE explains it is defined as the first full moon after the Harvest Moon, which itself falls nearest the September equinox. Because the Harvest Moon landed on September 26 in 2026, the following full moon on October 26 became the Hunter's Moon; if the Harvest Moon instead falls in October, the Hunter's Moon shifts into November — something that will next happen in 2028, per WEB.DE.

WEB.DE also notes regional names for the same October full moon, including 'Weinmond' (wine moon), tied to the grape harvest in German-speaking regions, and 'Blutmond' (blood moon), whose origin is unclear and which it distinguishes from the reddish Moon seen during a lunar eclipse.

This Week's Moon

Across the week of October 19-25, 2026, the Moon is in its waxing phase, moving toward the October 26 full moon, according to the lunar calendar published by DESIRED.DE. That waxing stretch leads directly into the Hunter's Moon on October 26, 2026, as reported separately by RMG and WEB.DE.