By Geoff Bansen

UPDATED – September 27, 2015

PHILADELPHIA (CBS) — With Pope-mania ensuing in Philadelphia this weekend, there is also another cool event happening tonight, also of a heavenly variety. A lunar eclipse is taking place, this one with a ‘super’ twist.

As you may already know, a lunar eclipse occurs when Earth moves between the sun and a full moon, with it’s shadow covering up our cratered comrade. What makes this eclipse so special you ask? For just the 5th time since 1900, a lunar eclipse will coincide with the “Supermoon,” the title given when the full moon is at it’s closest distance to Earth. The moon will be both 7% closer and about 30% brighter it is slightly closer, a subtle difference to the human eye but still discernible.

The eastern half of the United States will be able to witness every phase of the eclipse from start to finish. The early stages will begin at 8:40 p.m. with the total eclipse lasting from 10:11 p.m. to 11:23 p.m.

Unfortunately, cloudy skies may spoil this rare show for the Delaware Valley. Stargazers will then have to wait a while for the next one as this lunar eclipse will be the last visible anywhere on Earth until 2018. The next eclipse of any kind will be a much rarer solar eclipse in 2017. As for the next Supermoon eclipse? Don’t hold your breath; it won’t occur again until 2033!