The harvest moon is traditionally the full moon that occurs nearest to the autumnal equinox – September 23, 2015 this year. Sunday night, September 27th, this year’s harvest moon will pass through Earth’s shadow. This eclipse is especially rare, since it occurs when the moon is the closest to the earth – the so-called “super moon”. So, the full moon on September 27th will be the brightest and largest of the year. Beginning at 9:07pm the moon will enter the darkest part of the shadow – the umbra. For the next hour the full moon will increasingly be eclipsed – less and less of the moon will be directly reflecting the sun’s light as more of the moon enters the earth’s shadow.
The full moon will gradually seem to disappear. At 10:11pm, the entire moon will be inside the umbra. At this point, no part of the moon will be directly reflecting sunlight. The disk of the full moon will be visible – but dramatically reduced in brightness and with a distinctive color. Instead of the usual bright, white light of the reflected direct sunlight, the moon will be illuminated only by the red-orange light passing through the earth’s atmosphere – the light from all the sunsets around the globe. The total eclipse will last for over 70 minutes. At 11:23pm the moon will begin to begin to leave the umbra reversing the process. At 12:30am the full moon will be back in its majestic glory.
Saint Vincent College Observatory and Angelo J. Taiani Planetarium will host an open house on Sunday, September 27 from 9pm to midnight at the Sis and Herman Dupré Science Pavilion. Viewing will take place on the plaza at the front of the building. Weather-permitting, telescopes will be available to observe both the moon and other deep-sky objects.
You will want to take advantage of this opportunity to see a total lunar eclipse. The next time a total lunar eclipse will be visible in our region will be more than three and a half years from now - January 20, 2019. However, in the meantime, an even rarer solar eclipse will occur on August 21, 2017. While we wait for the next lunar eclipse, the moon will pass directly between the earth and the sun so its shadow will be cast along a path that will cross the United States. While the entire sun will not be blocked here in Latrobe, about 90% of the sun will be obscured by the moon. Travelling south to Kentucky, Tennessee, or South Carolina will be necessary to see the total eclipse that day. While this solar eclipse is still twenty-three months in the future, some are beginning to plan summer vacations to be in the path of the total eclipse.