NASA said a total lunar eclipse will be visible over the night sky in various countries for the second time in 2022 on Tuesday. .A blog post said a portion of the eclipse will be seen in eastern Asia, Australia, the Pacific, and North America. Weather records show the eclipse will be fully visible in Calgary. .NASA Marshall Space Flight Center astrophysicist Alphonse Sterling said eclipses happen once every one-and-a-half years on average. The blog post said people should take advantage of it because the next one will not happen until 2025. .An eclipse occurs when Earth casts a complete shadow called an umbra over the Moon. Earth’s shadow is categorized into two parts: The umbra, the innermost part of the shadow where direct light from the sun is fully blocked, and the penumbra, the outermost part of the shadow where some light is restricted. .During a total lunar eclipse, the moon and the sun are on opposite sides of Earth. Lunar eclipses are possible when the orbits align, so the moon is behind Earth relative to the sun..The blog post said a partial eclipse will begin at 2:09 a.m. MST, with totality commencing at 3:16 a.m. and ending at 4:42 a.m. It said the partial phase will resume after, lasting until 6:49 a.m. .Another feature of the eclipse will be the moon’s red hue during totality. The red color occurs because of the refraction, filtering, and scattering of light by Earth’s atmosphere. .The scattering is a phenomenon called Rayleigh scattering, which is named after British physicist Lord Rayleigh. .Light from the sun collides into the gases of Earth’s atmosphere and because of its shorter wavelength, blue light is filtered out, but red light is not because of its longer wavelength. Some of the red light is refracted, as it passes through Earth’s atmosphere and ends up shining on the Moon. .The degree of redness of a fully eclipsed Moon can be influenced by atmospheric conditions from volcanic eruptions, fires, and dust storms..Marshall astrophysicist Mitzi Adams said astronauts on the Moon during the eclipse would see a red ring around a silhouetted Earth..The blog post concluded by saying no special eye protection is needed for viewing this eclipse. While it can be observed with the unaided eye, a pair of binoculars or a telescope can enhance the view.
