Lunar Eclipse - Februry 20, 2008
Greetings Hopkins, NWC and NSO students. It was a perfect night for lunar
eclipse viewing in Minnesota. The temperature was -2F, the sky was crystal clear,
once these wispy clouds blew away, and the "seeing" was great because
there was no wind and a real stable atmpshpere. Under these wonderful conditions,
I set up the telescope and camera at the front of our house in Plymouth and
waited for the last lunar eclipse until 2010. The waiting was worth it, and
it was relatively easy to run outside to the front yard, take a few pictures,
and go back into the house and keep the camera warm. What is in this page is
a series of pictures that I took. I attached a Canon 10D camera directly to
the back of a Meade 10" Schmidt-Cassegrain Telescope with a focal-reducer
in between so I could maximize the light gathering power, but keep the Moon
images within the frame of the camera ... barely.
During the evening hours of February 20 (Wednesday evening), beginning at
7:43, the shadow of the Earth slowly crept across the face of the Moon. By 9:00,
the Moon was fully eclipsed, and stayed that way for 51 minutes. At the height
of the eclipse, Saturn could be easily seen to the left of the Moon, and Regulus
was above the Moon, making a very pretty triangle of celestial lights. Since
was the last lunar eclipse visible over North America until December, 2010,
I was thrilled to witness the event, especially since the previous lunar eclipse
over Minnesota was obscured by clouds..
The image above comes from SpaceWeather.com.
You can click on their site to get more details of this event, but by the time
you do that, the webpage will be covering other details of more current relevancy.
This particular geometry pictured above shows that the aligmnent is not quite
perfect, leaving the bottom of the moon near the edge of the umbra, which is
the darkest part of the shadow. As a result, the bottom of the Moon was lit
in a whiter shade while the rest of the Moon took on the traditional coppery
color. Remember, the coppery color of the eclipsed Moon is caused by the Earth's
atmosphere. While the Moon is in the shadow of the Earth, and you might expect
a completely darkened Moon, sunlight still leaks through the "rim"
on atmosphere surrounding the disk of the Earth. The atmosphere scatters the
blue light, but allows the red, yellow, and orange wavelengths to pass through,
bounce of the Moon, and be reflected back to the dark side of the Earth. During
different eclipses, the color of the Moon can vary between bright orange to
dark brown. These color variations are a direct result of global pollution from
large fires, volcanic eruptions, or other forms of atmospheric dirt. The dirtier
the air, the darker the eclipse. The cleaner the air, the brighter orange the
eclipsed Moon will be.
7:30 pm ISO 200, 1/1000 exposure
7:45 pm ISO 200, 1/1000 sec exposure
7:55 pm ISO 200, 1/1000 exposure
8:20 pm ISO 200, 1/500 sec
8:45 pm ISO 200, 1 sec exposure
8:55 pm ISO 200, 1 sec exposure
9:10 pm ISO 200, 1 sec exposure
9:20 pm. Saturn to the left, and Regulus above.
200 mm F2.8, ISO 200, 10 sec exposure
I have already created an Eclipse page
within the Astronomy online curriculum where you can go and learn the details
behind eclipses, why they are rare events, and why the color of the Moon is
red-orange instead of black.
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