Where:

Frosty Drew Observatory

When:

Friday September 18, 2015 at 7:30 p.m.

Cost:

$1 Suggested Donation per Person

Tonight's forecast is calling for mostly clear skies with possible periods of fog. The 25% waxing crescent Moon will be with us until 9:45 p.m. offering up stunning views of the thin crescent and Earthshine. The phenomenon Earthshine happens when the Moon is in a crescent phase and sunlight reflecting off of Earth illuminates the shadow side of the Moon. Aside from the chance of fog, tonight looks to be an excellent night.

We plan to open the Observatory and Sky Theatre at 7:30 p.m. In the Observatory, telescopes will feature Saturn and the crescent Moon to start. Once darkness sets in, we will direct our views towards blazing star clusters, stunning nebulae, and striking binary star systems. In the Sky Theatre a showcase of celestial objects we photograph at Frosty Drew Observatory will be featured. We will stay open until the fog chases us out or the night slows down. We will post a “Closing up” message when we call it quits.

Though fog is in tonight's forecast, we may see overall clear skies. If fog can stay out we will be in for a great night. Following us on Twitter (@FrostyDrewOBSY) or Facebook will get you updates on conditions at the Observatory and a final “Closing up” message when we decide to pack it in. So stop in and have a quiet late summer night out under the stars at Frosty Drew Observatory, tonight.

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Weekly Happenings
Scott MacNeill

Tomorrow night (Saturday, September 19), International Observe the Moon Night (InOMN) returns to Frosty Drew Observatory. InOMN is a global celebration for the Moon that thousands of universities, museums, libraries, and science institutions take part in. Throughout the year at Frosty Drew Observatory, we usually bag on the Moon. It is quite bright as it reaches gibbous and full phases and overall brightens up Earth's atmosphere to the point where dim celestial objects become unobservable. Though we often forget how amazing the Moon is, how awesome it looks in the telescope, and what it means for all of us here on Earth. So tomorrow night, we will make up for all that complaining with a night dedicated to just the Moon. Stop in an have a true lunar geek-out with us! Read about it

On Sunday, September 27, 2015 we are in store for an awesome night as three notable events are happening together! First, it is the Harvest Moon, probably the most popular full Moon of the year. Secondly, it's also the yearly lunar perigee, which is the point in the Moon's orbit around Earth that it is closest for the year. This makes it a Supermoon. Third, a total lunar eclipse is taking place and it's the fourth eclipse of the current Lunar Tetrad (four total lunar eclipses consecutively). Add in all those specifics and this is truly a rare event!

Lunar eclipses happen when the full Moon passes into Earth's shadow, effectively blocking direct sunlight from illuminating the lunar surface. Since the Moon is tilted 5.1° from the Ecliptic (plane of the solar system and path the Sun takes through the sky), the Moon does not always pass through Earth's shadows during its full phase. Earth's shadows are called the Umbra (full shadow) and the Penumbra (partial shadow). Sometimes, the Moon passes into the penumbra, called a “penumbral lunar eclipse”, during which we will see a slight dimming of the Moon on either the top or bottom hemispheres. Though the lunar eclipses we remember and those we see so many photos of are when the Moon passes into the Umbra and into full shadow.

We often hear total lunar eclipses referred to as a “Blood Moon” or a “Red Moon”. These common names have gained in popularity due to the deep shade of red the Moon takes on during a total lunar eclipse. This happens as a result of Earth's atmosphere, which scatters blue light. The blue side of the visible light spectrum has a much shorter wavelength than the red side, making it vulnerable to scattering by molecules in Earth's atmosphere. This is why the sky is blue. Notice when viewing the Sun on a hot humid summer day at sunset, it is much more red than it is during the day? This is because light from the Sun, visibly on the horizon, has to pass through more atmosphere than it does at midday resulting in an increase in the scattering of blue light. The red side of the spectrum passes through Earth's atmosphere largely unhindered by the molecules that scatter the blue light. When the Moon is in total eclipse or inside Earth's umbra, some sunlight passes through Earth's atmosphere and onto the Moon. Though most of the blue wavelengths have been scattered and remain in Earth's atmosphere with the red wavelengths passing through and illuminating the Moon. Anything that increases the density of Earth's atmosphere, volcanic ash, wildfire smoke, etc will increase the darkening of the Moon during an eclipse making it appear a deeper shade of red.

Frosty Drew Observatory will be open for the stunning lunar eclipse starting at 8:00 p.m. on Sunday, September 27th. Visibly, the eclipse will start at 9:07 p.m. as a partial eclipse, which will appear as a growing chunk missing from the western side of Moon (left side from our view). Total eclipse will begin at 10:11 p.m. and continue until 11:23 p.m. It is during this time that the Moon will appear a crimson red. Once total eclipse ends, partial eclipse will continue until 12:27 p.m.

Mark your calendars for this event as it is the last total lunar eclipse for us in the USA until January 2018. So grab a lawn chair, your family and friends then head out to Frosty Drew and catch the last total lunar eclipse of the current lunar tetrad. Read about it.

-Scott