Opposition surge from the retroreflective lunar soil brightens the area around Buzz Aldrin's shadow during Apollo 11 (photo by Neil Armstrong).. The opposition surge (sometimes known as the opposition effect, opposition spike or Seeliger effect [1]) is the brightening of a rough surface, or an object with many particles, when illuminated from directly behind the observer.

1993年4月23日 · The opposition effect, the sharp surge in brightness of an astronomical object observed near zero phase angle, which has been known for more than a century, has generally been explained by shadow hiding. The reflectances of several Apollo lunar soil samples have been measured as a function of phase angle in linearly and circularly polarized light.

Theory of Reflectance and Emittance Spectroscopy - January 2012

2019年8月9日 · The opposition effect is typically observed at phase angles less than approximately 10° and was thought for most of the time since its initial discovery to result solely from the hiding of the shadows of the rocks and other irregularities in the terrain. This phenomenon is known as shadow hiding, and this occurs when all shadows, from the ...

2024年12月16日 · The Opposition Effect derives its name from the fact that it significantly enhances the brightness of celestial bodies like the Moon and Mars when they are near the antisolar point in our sky. During opposition, these celestial bodies are in a position where the Sun, Earth, and the celestial body are almost in a straight line.

2018年4月15日 · The opposition surge refers to an addition sudden brightening at very small phase angles. The existence of such a surge was first noticed by Thomas Gehrels, in 1956, while studying the light curve of an asteroid. He coined the term opposition effect to …

The opposition surge (sometimes known as the opposition effect, opposition spike or Seeliger effect [1]) is the brightening of a rough surface, or an object with many particles, when illuminated from directly behind the observer.The term is most widely used in astronomy, where generally it refers to the sudden noticeable increase in the brightness of a celestial body such as a planet, …

2006年8月21日 · Two images of Saturn's A and B ring showcase the opposition effect, a brightness surge that is visible on Saturn's rings when the Sun is directly behind the spacecraft. This view is of the A ring. See Opposition Surge on the B Ring for the view of the B ring. The opposition effect exists because of two contributing factors. One is due to the fact that the …

where B 0 is the amplitude of the opposition effect, the h is the width of the opposition effect and g is the phase angle of the observation. This expression has been used to model the opposition effect down to phase angles as small as a few degrees. The size of the opposition effect B 0 is a function of the single-scattering albedo and the angular scattering function of the regolith …

The Opposition Effect of the Moon: The Contribution of Coherent Backscatter Bruce W. Hapke,* Robert M. Nelson, William D. Smythe The opposition effect, the sharp surge in brightness of an astronomical object observed near zero phase angle, which has been known for more than a century, has generally been explained by shadow hiding.