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The Great American Eclipse as seen in Tennessee
August 21, 2017 1:30pm local time.
By John Rubacha


Surreal, unreal and magical are the words I would use describe the Great American Solar Eclipse 2017.

By pure luck I was able to find a last-minute Holiday Inn Express motel in Campbellsville, KY.  I will not post the price I had to pay, but it was nice to have a real bed, Wi-Fi and plumbing.  At 3:00 am of the morning of the eclipse day, based upon weather.com, I made a decision to drive to the I-40 Smith County Rest Area in Lancaster TN.  This site was about 300 feet north of the centerline. 

I got there by 5:30 am and it was already packed with people who apparently slept in their cars overnight.  Also by pure chance, a "real interstate traveler" had pulled out and I got a nice parking space.

By 8:00 am, I had set-up my scopes and begin to offer views to an ever-increasing crowd of curious onlookers.  The TN state police had allowed cars to park in the grassy areas but eventually closed this location as they estimated over 5000 people were there.  I think the state police had also closed Interstate 40 in this area during totality!  The rest area staff had also turned off the power to the streetlights so they would not come on during totality.

More luck:  At about noon time some small Cumulus clouds started to form, but when the temperature had dropped these evaporated and the sky became a beautiful clear blue color and everyone knew we had lucked out on the weather.

Totality:  The last 30-60 seconds before 100% totality cannot fully be described as the Moon's shadow changes the ambient light and rapidly drops into a spectral color that I have never seen before.  It was almost like the Sun was being controlled with a giant dimmer switch.  Obviously things get dark, but with a blue-gray monochrome tint.  Green leaves and grass had become devoid of true color.  I almost felt like I was watching the world with black and white eyes.

Then at the first appearance of the solar corona, the crowd goes wild with a football touchdown cheer.  I then started my pre-programmed camera exposures, spent 2-3 seconds to check it was actually working, and went to watch the eclipse LIVE through the 8-inch Dobsonian scope and with my eyes.  The camera cannot capture the full range of light seen with the human eye through the scope.  I could see both the inner and outer corona and small prominences.  Some prominences were indeed deep H-alpha red, but others appeared almost orange.  I am not sure how the other colors appeared in the prominences, but the effect seemed real. 

The 2 minutes and 39 seconds passes by all too fast. 

Here are some photos I had taken of the eclipse and a few of the scopes and curious onlookers.  I am not in any of the pictures.  I had met lots of people from NY, NJ, Michigan, Arizona, and even a professional photographer from Sweden with an old time Pentax 6x7 film camera.

All exposures on the white Stellarvue 80 APO refractor were done with a DSLR controlled by APT (Astro Photography Tool v3.33).  Since I did not want to miss the eclipse by spending all my time trying to photograph it, APT comes to the rescue. 

There are over ten orders of magnitude of exposure levels during the eclipse.  I wanted to cover the diamond ring effect all the way through the outer corona.  This required (at ISO 100), about 1/4000 seconds through 4 seconds of exposure.  I spend about two months practicing trial exposures with the SV80 scopesand a solar filter to iron out problems in getting all this to work together. 

Of course, you cannot practice without a solar filter on the scope.  So the total eclipse becomes the "final exam" for all of your preliminary work and planning.  This is no repeat and try again tomorrow.  In my case and with more luck, it actually worked. 

I would consider this event an incredible success and a trial experiment for the next US eclipse in April 2024.
John Rubacha

Equipment and Pictures.

Two telescopes both with solar filters.  The large red Dobsonian telescope and filter was also used in May 1994 for the annular eclipse held for the public on the Purdue University Mall in West Lafayette, IN The smaller scope is a Stellarvue 80mm APO refractor at f6.0
Close up of the Stellarvue 80mm APO refractor.  At the time of 100% totality, the solar filter was removed for all images.

The Canon T5i was controlled with APT (Astro Photography Tool v3.33) to automatically bracket a series of exposures from 1/4000 seconds to 4 seconds. 

Unfortunately, each picture also required a one second “settling time” to minimize telescope vibration due to DSLR mirror flop and about 2 seconds of transfer time to process and send the raw and jpeg images into the laptop.  This extra time all comes out of your total budget of 159 seconds of totality.
A low-tech, but extremely useful reflector telescope.
An estimated several hundred people saw images through the home built 8-inch Dobsonian reflector with the large solar filter.  This allowed for a wide field view of the pending solar eclipse.  A few of us actually saw live totality views with filter removed.  For eclipses, the human eye will surpass the exposure range of any DSLR camera.

Many individuals also tried to capture images before totality with their camera phones.  Most people actually got decent images if they could hold the camera sensor steady and centered about one inch away from the eyepiece.
Eclipse Inner Corona.

Stellavue 80mm telescope at f6.  No solar filter.
1/125 second exposure time at ISO 100
Eclipse Diamond Ring Effect.

Stellavue 80mm telescope at f6.  No solar filter.
1/4000 second exposure time at ISO 100
Eclipse Outer Corona.

Stellavue 80mm telescope at f6.  No solar filter.
1/2 second exposure time at ISO 100
What appears to be a blue spot in the upper left, is actually the star Regulus in the constellation of Leo the Line.  At this exposure setting, the image of the star actually recorded.
Eclipse Solar Flares

Stellavue 80mm telescope at f6.  No solar filter.
1/1000 second exposure time at ISO 100