Kolkata: Late on Tuesday night, people across the country will get to see a partial lunar eclipse, which will last for approximately three hours. Starting at 1.31am on July 17, the eclipse will peak at 3am, when the shadow will be darkest, said experts. The eclipse will be visible from all parts of the country for its entire duration. “The shadow will be composed of two cone-shaped parts, one nested inside the other,” said Debiprasad Duari, the chief of MP Birla Planetarium. “The outer part of the earth’s shadow, called penumbra, is formed when the sun’s rays are partially blocked. The central part of the earth’s shadow, the umbra, is formed when all direct sunlight is blocked from reaching the moon’s surface. A partial lunar eclipse occurs when only part of the moon passes through the umbra,” Duari explained. According to experts, the moon will appear dim red in colour due to the little sunlight scattered on its surface. “According to scientists, the magnitude of the partial lunar eclipse will be 0.65, which means that during the peak, 65% of the moon’s diameter will be under the earth’s shadow,” Duari added. Unlike a solar eclipse, this event can be seen with the naked eye, without protective lens. Experts said those who are keen to witness the celestial event must not let this opportunity slip as there will be no proper lunar eclipse in India until May 26, 2021.