Lunar observation

Lunar nearside with major maria and craters labeled

Earthshine reflecting off the Moon. The bright region at left is directly illuminated by sunlight, while the rest of the Moon is faintly lit by sunlight reflected off the Earth.

Generally, the Moon can be viewed even with the naked eye, however it may be more enjoyable with optical instruments. The primary lunar surface features detectable to the naked eye are the lunar maria or "seas", large basaltic plains which form imaginary figures as the traditional "Moon Rabbit" or familiar "Man in the Moon". The maria cover about 35% of the surface. The contrast between the less reflective dark gray maria and the more reflective gray/white lunar highlands is easily visible without optical aid. Under good viewing conditions, those with keen eyesight may also be able to see some of the following features:

1. Bright region around Copernicus
2. Mare Nectaris
3. Mare Humorum
4. Bright region around Kepler
5. Gassendi region
6. Plinius region
7. Mare Vaporum
8. Lubiniesky region
9. Sinus Medii
10. Faintly shaded area near Sacrobosco
11. Dark spot at foot of Mons Huygens
12. Riphean Mountains

Another interesting phenomenon visible with the naked eye is Earthshine. Best visible shortly before or after a new moon (during the waning and waxing crescent phases respectively), Earthshine is the faint glow of the non-illuminated (night) side of the Moon caused by sunlight reflecting off the surface of Earth (which would appear nearly full to an observer situated on the Moon at this time) and onto the night side of the Moon. By the time the Moon reaches first its quarter however, the sunlight illuminated portion of the Moon becomes far too bright for Earthshine to be seen with the naked eye, however it can still be observed telescopically.

Binoculars are commonly used by those just beginning to observe the Moon, and many experienced amateur astronomers prefer the view through binoculars over that through higher-power telescopes due to the larger field of view. Their high level of portability makes them the simplest device used to see more detail on the lunar surface than what is visible to the naked eye.

The primary disadvantage of binoculars is that they cannot be held as steadily unless one utilizes a commercial or homemade binocular tripod. The recent introduction of image-stabilized binoculars has changed this to some extent; however, cost is still an issue.

A 10× pair of binoculars will magnify the Moon approximately as much as a 200mm camera lens can. The photos below were shot with a 200mm lens. The first photo was taken on 13 November 2016 at 6:20pm PST, observing the full Moon just hours before it would officially become the largest supermoon since 1948. The second photo was shot 24 hours later, and the contrast was enhanced to bring out details such as mountainous terrain. The next supermoon will not occur this large until the year 2034.

• 
  Pre-supermoon on November 13, 2016 (2016-11-13), at 6:20 pm PST, just a few hours before it would be officially called the "Supermoon of 2016"
• 
  Supermoon officially on November 14, 2016 (2016-11-14), at 7:19 pm PST

To some it may be more desirable to utilize a telescope in which case far more options for observing the Moon exist. Even a small, well-made telescope will show the observer much greater detail than is visible with the naked eye or small binoculars. As the aperture of the telescope mirror (in the case of a reflecting telescope) or lens (in the case of a refracting telescope) increases, smaller and smaller features will begin to appear. With large amateur telescopes, features as small as 0.6 miles (1 km) in diameter can be observed depending on atmospheric conditions.

Most astronomers use different kinds of filters in order to bring out the contrast of certain surface features. Simple neutral density filters are also common as they can cut down the amount of light reaching the eye by 60–95%, something that is helpful especially when observing a full or gibbous moon so the surface does not appear as washed out.

A number of observers employ different colored filters to determine colored transient events on the Moon. By quickly alternating filters of opposing colors in the telescopic light path, faintly colored areas on the Moon can stand out more by appearing to flicker on and off. A red area will appear brighter when viewed through a red filter and darker when seen through a blue filter. It is possible to alternate the filters manually however, this requires a certain dexterity of the hand and good coordination. A purpose built filter wheel is much more viable alternative, and this can be motorized, so the observer can devote all of their concentration to what is going on through the eyepiece. There are, however a number of features on the Moon that will appear to blink naturally, among them being the southwestern part of Fracastorius (crater), and a section of the western wall of Plato (crater). A special filter wheel called a "crater extinction device" is capable of measuring the brightness of an individual lunar feature to be measured according to the point where it ceases to be visible.