Total lunar eclipse to occur early Tuesday morning

Early morning sky watchers have a chance to observe a total lunar eclipse Tuesday morning depending on the amount of cloud cover over the area. The eclipse is set to begin at 1:33 a.m., according to NASA's website, with totality taking place at 2:41 a.m. The moon will be covered by Earth's shadow for a period of 72 minutes and the entire event is expected to last around three and a half hours. While the eclipse will be visible throughout North America, as well as other parts of the world, area residents may have some difficulty viewing the event. According to the forecast from the National Weather Service in State College, mostly cloudy skies are expected overnight tonight and there is a slight chance of snow showers, both of which could obscure the view for observers. A lunar eclipse can occur only during a full moon, and a total lunar eclipse, such as the one set to take place Tuesday morning, only occurs when the entire moon passes through Earth's umbral shadow, which prevents direct sunlight from reaching it. While the moon is within Earth's shadow it will appear a red-orange color. NASA's website explains that "although the physical mass of Earth blocks all direct sunlight from the umbra, the planet's atmosphere filters, attenuates and bends some of the sun's rays into the shadow. The molecules in Earth's atmosphere scatter short wavelength light (e.g., yellow, green, blue) more than long wavelength light (e.g., orange, red). This process, which is responsible for making sunsets red, also gives total eclipses their characteristic red-orange color. However, the exact color can vary considerably in both hue and brightness."For more on this story, see the Dec. 20th edition of The Daily Press.