obscuration
1.Deal with the causes of obscuration, not with the sun.
2.The period of time during which such an obscuration occurs.
3.Effect of Central Obscuration Interferograms Fitted with Zernike Circle Polynomials on Calculating Seidel Aberrations
4.In a word, the Tang Dynasty was the critical period in the transition of the art of the vocality skill from the ancient obscuration to the middle development, and its development in vocality art laid a solid foundation for the flourish of song art after the Song Dynasty.
