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This year I did another Xmas tree based on the success of the one I did in 2007. I made it bigger (9m = 30 ft) and more spectacular by using a different technique. It still uses a long exposure (2 min) and a rotating colored filter with the tree shape outlined by sparks from a rotating rod on top of the Tesla coil. This gives the "Eye of Sauron" effect. Imagine then if that rotating rod is able to be raised from horizontal to vertical while still rotating.
Early ideas
2009
Problem is that when colours are applied, the sparks are brighter than the streamers.
The streamers have poor colour saturation, particularly in the desirable tree color of green. So a modification was called for to allow continuous sparks towards the end of the rod.
Getting closer. This is an example of continuous sparks rather than streamers. The colors are more intense and any color looks good. There is a minor problem in that the sparks are bunched up. Depending on how the filters are shifted the above effects can be seen depending how the filter wheel rotated and how fast,
Here is another version closer to the desired effect. More spherical in shape but more tree like with the TC secondary being the trunk. Now just have to tidy up and fit Santa in. Oh, and make a star...
The left photo above shows the 10 dead fluorescent tubes covered with orange cellophane that comprise the final star. This is strung up by ropes so that it is 30 feet to to top point. The center photo shows the star lit by induced currents only. The right photo shows the star lit with direct flow of current from the TC to earth via the star and is much brighter. So much so that it leaves a prominent lens flare duplicate of the star. This is actually present in the final photo as well but is covered by a lot of other sparks. There is a lot of blurring due to wind here.
But to go back to the beginning
of the star development ....
The left photo shows a simple small (5 ft) star made of CD's. They did work as expected (right photo) but would probably start burning with flames towards the end of a run. A bigger star might use 50 CD's or more and doesn't allow for many trial runs.
Above is an animated gif of the burning CD's in a simple linear star. It works but is a bit tedious.
Construction
2009
The rotating arm is shown here from a lowered position to midway then up fully.
Here, I have attached a small spray of fibreoptic lights which show the spiral course of the tip of the arm.
The left photo shows me casting a fishing line aiming for a space in the upper branches. This was used to pull through a rope between two trees which gives me a suspension point 9 m (30 ft) in the air. In fact this was too low and I later aimed for the highest branches at 14m (45 ft). A convenient "skyhook" to hang the star and also the wire that elevates the rotating rod. The top of the star ended up at 9m (30 ft) for this tree which was twice the height of the 2007 tree.
This shows the pulley arrangement attached to the rope which is earthed (grounded) by the black wire that goes to RF earth in the right photo which is a pipe hammered a few feet into the ground.
The left photo above shows a close up of a double exposure with my foot and sparks hitting the ground. The center photo shows Santa checking framing and focus. It only just fits on my 18mm lens. Note the rotating filter in front. Santa's helper is in the right photo - the wife Jane - who controls whether I live or die. She calls it "quality time".
Special effects
2009
First there is a flash of Santa with the Tesla coil power OFF. He never gets close to any sparks because it is dangerous, remember. Small point is that the rod is hidden behind the Tesla coil which is well illuminated. For this to work the area behind Santa needs to be far away and black so it doesn't get lit by sparks and show up on top of Santa in the long exposure. Next, Santa turns on the rotating rod and runs away! In darkness so you don't see that on camera. The filter is changed to green and the Tesla coil turned on.
The composite demo shot illustrates the rotating rod in view and sparks from the rod to the ground. After some rotation the filter has been changed to green so the only illumination (the sparks) is now green. In the actual shot you never see the rotating rod because it is never still in one spot so just blurs out of view.
Ooops, In this demo shot I tripped over the camera tripod in the dark and ended up with a double image above. Nevertheless, it does demonstrate the several rotations of green at the base. In the actual shot, the TC is turned off while I (Santa) pulled on the line to raise the rotating rod and rotating the green filter to red. Note the star is lit brightly as all current is now passing through it. It overexposes but time was too short to fix that and it just makes it appear brighter.
Then all that remains (above) is to continue to raise the rod while changing to yellow and then green filters in turn. Then the exposure is stopped using a radio remote to avoid jitter. Total exposure 2 minutes, f/7.1, ISO 500 on 12 MPx Nikon D300 Needless to say there is a lot happening in 120 seconds. It needs reasonable timing in near complete darkness. So quite a lot of trial runs and stuff ups.
This photo in the media
2009 The links to the other 100 or so websites are here - search for "Xmas 09" The video went to Win/Channel 9 and was shown in Western Australia. I will put the footage here when available. Has reached No 494 on Google images for Xmas out of 30,000,000.
Tesla Christmas tree 2007
Merry Christmas! This is a single photo from a Nikon D70s digital camera and is a
91
second exposure of a real functioning Tesla coil and is the result of
perhaps 50 hours of preparation. It is cropped but otherwise completely untouched. It is not, repeat not, photoshopped.
It does however achieve the result using special effects which I will
explain.
Above is the very dull video showing the sparks being patiently and slowly guided inside the confines of the frame. Otherwise there is complete darkness until the final flash that illuminates me at the end when I am in position. There are no color filters on the video. Imagine all the sparks you see adding up to the final photo.
Early ideas
2007
Here is an early setup in testing showing the less than full sized frame of the tree. By making sparks between the rod that I control and the frame, I should get a tree shape. Various testing was done to work out the best techniques.
The Star first attempt
2007
As a test I have mounted my Nikon D70s camera in a small Faraday cage so I
can take a picture looking directly down on the Tesla coil. This
"skycam" is shown suspended about 17 feet in the air ie 10 feet above the TC
using a wide angle lens. It is in a custom support which is rain/sun/EMF
resistant yet able to pass IR from the font to allow the long distance
remote control to work. Also the flash can be used.
This star is more floral than astronomical so I didn't use it. It hasn't been as star shaped as I would have liked. Everything except the sparks are blurred because there was wind moving the camera - even at 10 pm when I had my final shot. Hence the round toroid and the circle of the breakout points are odd shapes. So on to further planning for a better star using the frame method.....
The left photo shows the frame with a star pattern held there by wire and fishing line. You can't see the star well as the line is very fine so it doesn't show up in the photo. The tree is a bit smaller than I had hoped for but the whole thing is still 15ft high. The right photo shows me holding a 3.2 m (10 ft) fishing rod with the end wired to the Tesla coil. I use this to place sparks to the frame. There is an earthed cable clipped on halfway. Probably unnecessary but is a safety measure. There is also a fine earth wire not seen here trailing between me and the TC.
Special effects
2007
The photos above show some early results with a green filter. The different colors are achieved by using my color filter setup. This gets changed during exposure and in the final shot the tree trunk sparks are red, the tree shaped sparks are green and the star sparks are golden.
The left photo shows the color filter setup in front of the camera that will need to be rotated manually at the correct time to change colors. The center photo shows the black screen that I am behind for almost all of the exposure except for the flash at the end. Not really sure if it was needed. The right photo shows me in the Santa costume. Inflatable and cost $29.99. Some unkind person intimated that I was well, portly, not realizing it was inflatable. One of my sons runs the camera and does the filter rotations at my signal, my other son does the video and my wife does the high voltage on/off, adjusting the voltage to give strong consistent sparks. After a few 90+ second runs the tungsten contacts had worn down and needed readjustment.
This photo in the media
2007
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This page was last updated January 24, 2010
