The second of four eclipses in a lunar
eclipse "tetrad" will occur over the course of the wee
hours of October 8th. This tetrad of eclipses is unique in that each
will be visible from parts of North America. We experience a lunar
eclipse when the Earth passes between the sun and the moon causing
Earth's shadow to block the sunlight from reaching the moon. Often
these events take place but due to the timing we may not be able to
see them. This is the second of the four that will take place in 2014
and 2015.
There are five stages to an eclipse that occur over the course of about three hours. The first is the penumbral stage, where the moon begins to enter the Earth's penumbra, or outer, lighter edges of shadow. Viewers might not notice changes in the moon at this point as the darkening is very slight. The second stage is the partial eclipse where the moon begins to enter the Earth's umbra, or the darker part of the shadow. The darkening will start on the moon's eastern side. The total eclipse is the third portion and this begins once the moon is directly in the darkest part of Earth's shadow, or umbra. The moon will glow red during the total eclipse due to sunlight. The moon moves back into a partial eclipse, and then finally back to the final penumbral stage as it moves out of Earth's shadow. Two factors will affect how dark the moon will look during the total eclipse portion: how deep into Earth's shadow the moon passes, and what the atmospheric conditions are at the time. For example, if there is a lot of dust in the atmosphere, then the moon will look darker. For those of us on the East Coast we will be able to see the total eclipse stage occur around 6:35 AM on October 8th. For a chart of the viewing times for other areas in North America, consult the link in the "read more" section below.
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| A lunar eclipse over Merritt Island, Florida (NASA) |
There are five stages to an eclipse that occur over the course of about three hours. The first is the penumbral stage, where the moon begins to enter the Earth's penumbra, or outer, lighter edges of shadow. Viewers might not notice changes in the moon at this point as the darkening is very slight. The second stage is the partial eclipse where the moon begins to enter the Earth's umbra, or the darker part of the shadow. The darkening will start on the moon's eastern side. The total eclipse is the third portion and this begins once the moon is directly in the darkest part of Earth's shadow, or umbra. The moon will glow red during the total eclipse due to sunlight. The moon moves back into a partial eclipse, and then finally back to the final penumbral stage as it moves out of Earth's shadow. Two factors will affect how dark the moon will look during the total eclipse portion: how deep into Earth's shadow the moon passes, and what the atmospheric conditions are at the time. For example, if there is a lot of dust in the atmosphere, then the moon will look darker. For those of us on the East Coast we will be able to see the total eclipse stage occur around 6:35 AM on October 8th. For a chart of the viewing times for other areas in North America, consult the link in the "read more" section below.
It is not always possible to view
astronomical happenings due to weather, obstructed views, light
pollution and clouds. Luckily there are many good digital programs
that model the night sky for us. One that could be particularly
useful to teachers when having students observe and understand the
phase changes of the moon is Stellarium. Stellarium is free, open
source software that allows you to "view" the sky for any
location and time. Although you won't be able to use it to experience
the total lunar eclipse, you can observe the moon's phase changes in
addition to seeing stars, planets, constellation charts, etc. from
your own device. Stellarium software is even being used in some
planetariums. Another free way to explore the moon is by using the
moon option in Google Earth. Google Earth is useful for many
educational purposes. You can explore the virtual moon globe and zoom
into images of the craters and alien surface of our satellite.
Although neither of these digital options is the same as heading
outside with some binoculars on a clear night, they work well when
there are obstacles for preventing you or your students from doing
so. Happy sky-gazing!
Read more:
Moon and Sky Resources:
Stellarium free open source planetarium
software
Google Moon- images and links to using
Google Earth to navigate the moon
Sallie Ride MoonKam activities
Although the GRAIL MoonKam mission is
over, there are many fun activities to try here!
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