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"I set up about 20 miles
East of Denver, between Bennett and Kiowa. I started
shooting at 12:12 and took a shot every 15 seconds
for three minutes. After that I took a shot every 10
minutes till the sun hit the mountains. Celestron
C8, focal reducer, Nikon D-100, Vixen GP and Baader
(white) Solar filter."
- Photo by Bryan Wilburn, DAS |
At several seconds after 12:12 pm (19:19
UT), hundreds of observers across the Mountain time zone shouted as a
tiny dark notch appeared in the SE limb of the Sun, not far
from a large solar prominence. Some observers could even see
Mercury pass over the prominence in hydrogen-alpha light
slightly before first contact. For the next four or
more hours, the transit provided a stunning demonstration of
the huge size of Sol, our star; the predictable physics of
the planets' elliptical orbits, and the true meaning of the term
"solar system."
The
Mercury transit of November 8, 2006 will be remembered in
Colorado for its fine weather (clear and warm), high public
visibility, and excellent viewing.
This was the first transit to occur following the wide
availability of inexpensive hydrogen-alpha filter
telescopes, and it was fitting that the day was perfect for
using those instruments, which showed incredibly sharp views
of Mercury's dark side suspended above the roiling red,
orange and yellow super-heated gases of the Sun's upper
atmosphere (or chromosphere), fully 29
million miles beyond Mercury's orbit.
Special thanks to Mike Nelson of
Channel 7, Nick Carter of 9News, Chris Parente of WB2, the
Rocky Mountain News, the University of Denver, and others for helping us
promote the 2006 transit viewing.
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9News Weatherman Nick Carter checks out the image
splitter that allowed visual and video viewing of
the Sun. Photo by Brad Gilman, DAS
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University of
Denver's Historic
Chamberlin Observatory
Well over 200 visitors
observed the Mercury transit through the famous
20-inch Alvan Clark-Saegmuller refractor in the
observatory.The 20-in f/15
telescope was fitted with an 8-inch Baader solar
filter on a square plate that extended well beyond the
objective, providing shade for the finder scopes and
observers.
A beam splitter designed and
fabricated by DAS president Wayne Green allowed
visitors to view the actual photons coming from the
Sun (and the absence of photons from Mercury), while
a video camera fed another image to monitors elsewhere in
the observatory.
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In
constant operation since 1894, the Alvan
Clark-Saegmuller refractor is tied with five
others as the 7th largest telescope of its type in
the United States.
The telescope was oriented in the
"weights high' configuration to prevent viewers from
having to climb too high on the observing gantry.
Photo by
Ron Pearson, DAS |
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 There
was a constant stream of visitors to the observatory
throughout the afternoon.
Visitors gaze up at the
28-foot-long Clark-Saegmuller Telescope (above) while they wait their turn at the
eyepiece.
The first published observations
associated with the great refractor were those of
Dr. Herbert Howe, the first observatory director, who
observed and documented the Mercury transit of November 10, 1894.
See Ron Pearson's
article for more historical information.
Photo by Brad Gilman, DAS |
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Mid-afternoon view from the
balcony of Chamberlin Observatory -Photo
by Brad Gilman, DAS |
Observatory
Park
About 15 telescopes of
various sizes and types were set up and attended by DAS
members in Observatory Park near historic Chamberlin
Observatory. Herbert Howe's wife and several students
observed the 1894 Mercury transit through a 6-inch Grubb
refractor in the student observatory (at far right in the
above photo.) The Grubb is now mounted on the 20-inch
refractor in the main observatory.
"For most of the afternoon, I had a
24mm Panoptic eyepiece (120 X) on my 9 1/4-inch Celestron
Schmidt-Cassegrain (full-aperture Thousand Oaks glass
filter), providing a fine, close-up view of Mercury's
intensely black dark side as it crept across the face of the
Sun. Most of the 100 or so visitors I had were were more
impressed with the views of prominences and solar surface
texture through the hydrogen-alpha PST that tracked with the
SCT. There were many probing questions and lively
discussions, indicating that the transit was helping people
see the Earth, the Sun, and the Solar System in a new way."
- Darrell Dodge, DAS |
The 40mm Coronado Personal Solar Telescopes (PSTs)
provided an excellent view of the transit in the hydrogen
alpha wavelength, despite their small size. Larger
versions of the scope gave even better views, of course.
Photo by Ron Pearson, DAS |
 DAS
member John Anderson (white hat at left) explains the operation and use of his
home-built solar spectrograph, which displays the full
spectrum of visible light from the Sun, showing the dark absorption
lines associated with the various elements found on the Sun.
John's telescope set-up featured white,
hydrogen-alpha, and calcium wave-length images. He first saw
Mercury silhouetted against the Sun's chromosphere (upper
"atmosphere") at 12:12:05 pm MST.
Photo by Brad Gilman, DAS |
DAS member Jack Eastman's classic 6-inch Alvan Clark
refractor was fabricated several years before the first
Mercury transit that was viewed at Chamberlin Observatory,
in 1894.
Photo by Ron Pearson, DAS |
Hats were the order of the day under the totally
cloudless skies. The weather was more like September than
early November, with a record Denver high of 81 degrees F.
Photo by Ron Pearson, DAS |
This young girl had one of the last clear views of the
transit at Chamberlin Observatory as the sun began to dip
behind the trees on the West side of Observatory Park about
4pm.
Photo by Ron Pearson, DAS |
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Virginia Court
Elementary School
"The first contact was most
impressive to me, and I remember how fast Mercury
penetrated into the Sun. Within a few seconds one could
see it surrounded by red. After that first look we spent
all of our time cycling 300 children at Virginia Court
Elementary School past our three white-light-filtered
scopes and one hydrogen-alpha 40mm Coronado PST. -
Dennis Cochran, Vic Burhans, Pauline & Cliff Ide,
working with teacher Nathan Schwalen."
- Dennis Cochran, DAS
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fine transit sequence shows the gradual extinction
of Mercury's image (right side) as the Sun and Mercury dipped
lower in the sky, increasing the negative effects of
atmospheric turbulence and the volume of air and
atmospheric dust and water vapor through which the
event was imaged. The sun set before the transit was
over in Colorado. |
Deer
Trail Colorado: DAS Edmund G. Kline Dark Site
"Taken at the Edmund G.
Kline Dark Site with my 10" f4.5 Newtonian stopped down to
2.75" with a Thousand Oaks glass solar
filter. Olympus E-Volt-500 camera used. Composite of 52
images done in PhotoShop®"
Photo by Joe Gafford, DAS |
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