Solar Eclipse 2017 From Sparta, TN

The August 21, 2017 Solar Eclipse as photographed from Sparta, TN (35.9727° N, 85.5638° W).   This was about 3.2 miles from the center of Totality!  These images do not convey the magnitude of the experience.  Knowing what to expect in general does not prepare you.  If I tried to find a single word to describe it, I would pick astonishing.


Location Sparta, TN (35.9725° N, 85.5638° W)
Duration of Totality 2m38.8s
Magnitude 1.014
Obscuration 100.00%
Event Date Time (UT) Alt Azi
Start of partial eclipse (C1) 2017/08/21 17:01:17 63.9° 154.8°
Start of total eclipse (C2) 2017/08/21 18:29:50.1 63.9° 205.4°
Maximum eclipse 2017/08/21 18:31:09.6 63.8° 206.1°
End of total eclipse (C3) 2017/08/21 18:32:28.9 63.6° 206.8°
End of partial eclipse (C4) 2017/08/21 19:56:17.0 51.9° 239.1°
Posted by Chad Dotson in Photography, 2 comments

July 8, 2016 Lightning

These are the first lightning photos in several months.  It was a good electrical storm but the lightning wasn’t so photogenic.

Posted by Chad Dotson in Misc, Photography, 0 comments

Estill Springs Fireworks 2015

These are photos taken at the Estill Springs, TN 2015 Fireworks show.

The Best

The Rest

Posted by Chad Dotson in Photography, 0 comments

DLSR Lightning Trigger 4

Success again!  This time the lightning trigger managed to capture a good bolt (though not as photogenic as I would have liked).  I ran into trouble again with my camera exiting the “Quick-response remote” release mode.  This caused me to miss more than a few events, but I did find the solution.  Buried in one of the custom settings is a timeout for the remote feature.  It defaults to 1 minute!  I’ve now set it at the max of 15 minutes.  Maybe this has worked some of the kinks out and the next storm will produce some good lightning opportunities.

Posted by Chad Dotson in Hobbies, Photography, Programming, Technology, 0 comments

DSLR Lightning Trigger 3


Finally Some Lightning … IT WORKS!

Tonight, I was finally able to deploy the prototype of my lightning trigger.  The storm wasn’t particularly photogenic, but it at least helped prove the concept.  Lightning was slim and no bolts were in the best area for my camera, but the camera did capture the image to the right.  Not very good I know, but if it will work for such a poor example of lightning, I think during a real storm it will perform splendidly.  My next steps are to research moving to a wired trigger (replacing an MC-DC2 ) instead of the IR LED, add a potentiometer to adjust the sensitivity in the field, and installing the circuit into a project box.

Lessons Learned / Observations

Perhaps this won’t be a problem during a storm with a lot of lightning, but one problem that I encountered was that the camera would exit the “Quick-response remote” release mode and return to my prior setting in the absence of regular input.  I guess this was due to the camera entering a suspended state.  I will have to see if I can modify this setting, if not I may attempt to keep the camera awake.

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Posted by Chad Dotson in Arduino, Hobbies, Photography, Programming, Software Engineering, 1 comment

DSLR Lightning Trigger 2

Lightning Drought

Back in September, I created a simple Arduino-based lightning trigger (original article).  I’ve been waiting since then for the chance to test the circuit in the field.  Yesterday provided the first real chance to test the circuit; unfortunately, I missed it.

Improving the Program

Even though I missed the event, I did decide to improve the program a little.  The major change, if it can be called major, addresses a weakness in the original program.  Originally, every event would attempt to trigger the shutter twice (once when the lightning occured and again when the brightness returned to normal).  To fix this I am removing the absolute value function from the brightness test.  Now, it will only trigger if the new brightness is brighter than the previous.


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Posted by Chad Dotson in Arduino, Hobbies, Photography, Programming, Software Engineering, Technology, 5 comments

On Software Engineering


Writing from the patio on a much deserved day off. What a day, sunny and 68 this 3rd day of spring. It sometimes makes it real hard to work inside in a windowless box. It’s been a busy day of a different sort, but dang I could get used to it.

Software Engineering Is Consuming

Software Engineering can and is absolutely consuming work.  The short of it is, we like what we do so we tend to focus a lot of attention on it.  We are problem solvers, designers, learners, and the list goes on.  I am of the philosophy that you should find and do something you like because anything else is a waste.  I guess that philosophy has its pros and its cons.  Is it so bad when your day consists of writing code, solving problems, researching, and learning new things?

Achieving Balance

I guess everyone talks about work/life balance and its true; you must always take time for yourself.  Get outside, do some walking.  It will help clear your head and it is a good stress reliever.  Maybe you’ll come back to the task with some fresh ideas and renewed vigor.  The schedule will always be there.

Personally as of April, I will have been on a diet and exercise plan for 2 years.  I’ve lost a lot and still need to lose more.  One of my biggest problems has been shorting myself on time to maintain my walking and weight lifting.  I seem to always get wrapped up in something.

Having a rewarding hobby is probably a good idea.  I’m not talking about coding a side project (don’t we all seem to have an overabundance of those), I’m talking about something else entirely.  My non-programming hobby is photography.  I don’t get to do it much it seems anymore it seems, but I do find winter a dreary time to take photos.  I did have a major accomplishment in this area last fall.  I officially photographed a wedding.  While I was originally scared to take on such a task, the photos turned out wonderfully.  I took the photo below today.


Bradford Pear Blooming Spring 2015


Posted by Chad Dotson in Hobbies, Key Concepts, Photography, Programming, Ramblings, Software Engineering, 0 comments

DSLR Lightning Trigger

June 15, 2011 Lightning CompositeLightning

I use my Nikon D5000 to take a lot of lightning photos.  This one to the right is a composite of several taken during a storm that produced a good amount of of photogenic lightning a few years back.  The photos that make up this one and many of my others were created using timed exposures of up to 30 seconds on length.  This is problematic, at times, due to other light sources, camera movement, etc.  Using simple, arduino-based circuit, we can create a device that will attempt to detect lightning strikes and trigger a camera shutter when one is detected.

Prototyping The Circuit

This circuit consists of 2 major pieces: lightning detection and shutter triggering.  To detect lightning, a phototransistor or photoresistor is required.  For this project, I used a photoresistor.  To trigger the shutter, a 940nm infrared LED is required.  These LEDs can be used to trigger cameras from Nikon, Canon, Pentax, Olympus, Minolta, Sony and possibly others.  Below is the complete parts list I used along with links to them on Amazon.


  • Arduino UNO R3 (buy)
  • Photoresistor 5mm GM5539 (buy)
  • 940nm Infrared LED (buy)
  • Yellow LED (buy)
  • 1 – 200 Ω Resistor (buy)
  • 1 – 100k Ω Resistor (buy)
  • Miscellaneous jumpers and breadboard (buy)


The Code

This circuit’s method of detecting lightning with a photoresistor is pretty simplistic.  It simply loops infinitely recording the analog input from the photoresistor, taking the difference of it to the saved value, and comparing that to the configurable threshold.  In its current configuration, it will take 2 photos per lightning strike.  This is the first iteration of this code, so I may change it to use a moving average instead of just the last recorded value.

To fire the IR LED in the right sequence, I used the Multi-Camera IR Control Library since it supports my Nikon D5000.  In addition to the D5000, this library supports Nikon, Canon, Pentax, Olympus, Minolta, and Sony cameras. If you don’t have a camera that is supported, a custom interface could easily be created with specifics for your camera model.


To The Field

Since the protoype is fully functional, I plan on fielding it during the next thunderstom.  I will report back once I see how it works along with any refinements.


As always, I have placed the code and diagrams for this project in a github repository.  It includes code that can be compiled and uploaded via the Arduino IDE and diagrams that can be viewed or edited with Fritzing.

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Posted by Chad Dotson in Arduino, Hobbies, Photography, Programming, Raspberry Pi, Software Engineering, Technology, 8 comments