Tom Thomson's Clouds (The Zeppelins) and Astronomy

 Sometimes in working on a puzzle, you must just plunge in and put a piece down and see what else fits. Such was the case with Tom Thomson's Clouds (The Zeppelins). That essential first guess piece was that Tom was looking southerly in the early evening from Canoe Lake.  

Clouds ("The Zeppelins") 1915 
Oil on wood 8 3/8 x 10 7/16 inches
Thomson's Paint Box Size 
National Gallery of Canada, Ottawa (4694)

Dots of White Oil Circled in another Image of 
Tom Thomson's Clouds (The Zeppelins) that
highlights the "random" white flecks of il 

The important second piece of the puzzle was to realize that Tom recorded exactly what he saw and that honesty is a big part of his genius. What are those white dots in the sky? With some artists, they would simply be flecks of random, white oil that got away. But not so with Tom, even though he was painting in the dark! The white flecks were stars illuminating the southerly sky with light just possibly completing a trip of 500 light-years or longer. 

I asked an astronomical friend for guidance. Paul Sheppard, from Brockville, Ontario was only given the first puzzle pieces as constraints: a southerly view from Canoe Lake in late April 1915 in the early evening of a full moon (another puzzle piece that I will get to explain in the next post). Paul and his astronomical friends discovered the following. 

Those white dots are indeed very large stars that are among the brightest in the night sky - amazing!

The accompanying video is from the "Tom Thomson Was A Weatherman" presentation. 

The result was a one-to-one correspondence between the white flecks of paint in Tom’s sketch to the brightest stars in the night sky. This was very convincing evidence that Tom painted exactly what he witnessed first-hand. Even further, the subject matter reveals an intense interest in the natural world.

The celestial side of this painting can be even more interesting. The 1976 pop song by England Dan and John Ford Coley gives a clue to what Tom painted. 

England Dan and John Ford Coley
 in 1976

“I'm not talking 'bout movin' in 

And I don't want to change your life 

But there's a warm wind blowing the stars around 

And I'd really love to see you tonight 

  

We could walking through a windy park 

Or take a drive along the beach 

Or stay a home and watch TV 

You see it really doesn't matter much to me”

The twinkling of stars in the sky is caused by aberrations in the optical path as that light passes through the atmosphere. If the air mass is cold and stable, stars do not twinkle as the optical path remains pretty much unchanged – typically smaller than the apparent diameter of the star. Many more stars can be witnessed in a cold sky.

If the atmosphere is turbulent such as must be the case with the approach of a warm front, the optical path of the light is jostled about as if countless lenses are bouncing around between you and the star. These lenses are simply pockets of warm air that bend the light away from a straight line path to your eye. The result is that the light from the star does not follow a straight path to your eye and the apparent location of the star is shifted-jostled about. The path of the light to your eye gets larger than the diameter of the star and the star “twinkles”. Hence the line “there's a warm wind blowing the stars around” is actually scientifically accurate. Another song comes to mind as well: "twinkle, twinkle little star".  I am not going to get into the time and space warping described by Einstein's theories. All true though!

If the twinkling is strong enough to “move” the star outside its steady state location, the result is that the light is smeared over a greater area than is actually occupied by the star, and the star is effectively dimmed by twinkling. More intense twinkling causes the light to spread over larger areas, resulting in the faint stars becoming undetectable. In warm frontal situations, only the largest stars and planets can twinkle and still be seen. The impacts of twinkling are most pronounced on smaller stars. 

To summarize, the planets and the largest stars are less prone to twinkling. They are larger than point sources of light so even if there was strong warm air advection in the atmosphere, the resultant turbulence cannot alter the path of the light from the planet or large star sufficiently to cause them to flicker or disappear from the perspective of the observer. 

To recap, we tried some puzzle pieces and they all fit with the help from my friends:

• Tom Thomson was at Canoe Lake
• Full moon night of April 29th, 1915
• Around 8 to 9 pm
• Those white specks were large stars and the brightest in the night sky
• Warm air turbulence in the upper atmosphere

I have taken some liberties with the full moon and warm air advection but those will be explained in the next post that will focus on the clouds.

If you managed to read this far, well done! This was certainly a journey for you. I know, it was a journey for me to figure it all out, even with the generous assistance of my astronomical friends. 

Tom had to paint that evening sky. We are as close as we will ever be to looking over his shoulder as he hunched over his paint box in the dim light and the chilly breezes of the evening of April 29th, 1915. This reality of the dedicated artist at work can be easily forgotten when we view the work in museums. I hope you might imagine what that evening might have been like for Tom Thomson. If you can, then this post has been successful for me as well. 

Warmest regards and keep your paddle in the water,

Phil Chadwick

PS: For the Blog Version of my Tom Thomson catalogue raisonné, Google Search Naturally Curious "Tom Thomson Was A Weatherman - Summary As of Now" or follow this link “http://philtheforecaster.blogspot.com/2022/10/tom-thomson-was-weatherman-summary-as.html”