Observations of a Lunar Eclipse

A Total Lunar Eclipse photographed on Aug. 16, 1989 near Hillsdale, Kansas, USA. Series starts at about 8:45pm and runs past 11:00pm, central daylight time.
photo (C)1989/1999 ICSTARS Astronomy by Vic Winter.


Descriptions of the phenomenon of the eclipse

During a total lunar eclipse, the Moon will never completely disappear. Even when it is at its maximum, a small amount of sunlight is bent or refracted through our atmosphere and into the Earth’s shadow. The refractive properties of the atmosphere cause light from the blue end of the visible spectrum to be scattered, while light from the red end is more readily passed, and results a reddish cast to the Earth’s shadow.      


*Different Views of the Total Lunar Eclipse.

A total lunar eclipse’s colour depends on the clarity of the earth’s upper atmosphere. Hence, when the air is free of particulate matter,  a vivid eclipse will be seen. When the atmosphere is polluted with foreign particles, such as volcanic aerosols, we can see a darker total phase.        



*Black totality: Dust from eruption volcano                 *Reddish cast to the Earth’s shadow.      *Affect of volcanic eruptions : the light is so suspended high in Earth’s atmosphere, most of the scattered that almost no light reached the Moon.

Sun’s rays reflected from the Moon are blocked.

 The brightness of a total eclipse depends on the distance of the Moon from the center of the Earth’s umbra. Presumably, the umbra’s central area is less polluted with refracted sunlight, leading to darker eclipses, brighter eclipses are more apt to occur when the Moon passes near the umbra.

 Partial eclipses of the Moon are spectacular events that always draw wide attention among amateur astronomers. Observers can time the exact moments when the umbra first touches and last leaves the lunar disk, monitor the changing colors and any unusual irregularities in the umbra, and time when the umbra crosses over certain select lunar features.         

During the partial phases, the shadow’s color is either dark brown, dark gray or black if the shadow is isolated from the portion of the Moon still uncovered by the umbra. But isolating the telescopes’ field of view only on the eclipsed portion of the Moon will enhance subtle colors and tints, the leading and trailing edges of the umbra are frequently characterized as coppery red, although some eclipses have worn a distinct blue or green fringe.


* Different Views of The Partial Lunar Eclipse                                                             *Trailing Umbral-Edge, 3rd Contact

         Of all solar and lunar eclipses, it is most difficult to view penumbral lunar eclipses. Indeed, the Earth’s outermost shadow is so weak that a penumbral eclipse may come and go completely unnoticed.

         Some penumbral events are more impressive than others.  Shallow penumbral eclipse with a magnitude of less than 0.7 and half of the moon’s diameter within the penumbra, is difficult to detect and attract little attention from the astronomers. Deep penumbral eclipse with magnitude greater than 0.7, is typically visible with or without optical aid.

Many people make systematic observations of the Moon’s appearance during total lunar eclipse. This can be done by rating both its apparent magnitude and its luminosity. Others carefully keep track of the Moon’s progress through the umbra by timing the Moon’s passage over distant stars. Some use the short period of darkness to search for new comets or make observations of existing comets and variable stars that are otherwise lost in the Full Moon’s glare.


          * Lunar Occultations

         The farthest north or south one is from this central region, the shortest the occultation’s duration. Too far north or south, and the Moon will miss the star entirely. A captivating sight is visible along the northern and southern edges of an occultation’s region of visibility across the Earth and the Moon will appear to graze over the star, alternately covering and uncovering the point of light as the star passes behind lunar mountains and valleys.