Lunar observation

The Moon may be observed by using a variety of optical instruments, ranging from the naked eye to large telescopes.

The brightness of a full moon as compared to a phase where a smaller percentage of the surface is illuminated tends to wash out substantial amounts of detail and can actually leave an afterimage on an observer's eye that can persist for several minutes.

Under good viewing conditions, those with keen eyesight may also be able to see some of the following features: Another interesting phenomenon visible with the naked eye is Earthshine.

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.

With large amateur telescopes, features as small as 0.6 miles (1 km) in diameter can be observed depending on atmospheric conditions.

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.

Due to the large apparent size of the Moon, lunar occultations are quite common and when a bright celestial object is involved, the result is an event that can be easily observed using the naked eye.

Four first magnitude stars, Regulus, Spica, Antares, and Aldebaran, are sufficiently close to the ecliptic that they may be occulted by the Moon.

Depending on one's location on the Earth, there are usually several occultations involving naked eye objects every year and many more that can be observed using binoculars or a telescope.

Claims of these phenomena go back at least 1,000 years, with some having been observed independently by multiple witnesses or some in the scientific community.

Nevertheless, the majority of transient lunar phenomena reports are irreproducible and do not possess adequate control experiments that could be used to distinguish among alternative hypotheses.

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.