7th UK Teslathon, Derby May 29th 2004.
More images of the event from other people : Adam Horden Derek Woodroffe
Thanks again to Martin Dale for organizing another great Teslathon.
See http://www.tcbouk.org.uk/ for more info on UK
teslathons past and future.
All pictures were taken with a Canon EOS 300D in full manual mode at ISO 1600 with either the standard (18-55mm) lens or a 50mm F1.4 lens, mostly . The latter lens was very good for tesla coil spark pics, as the wide aperture allowed a short enough exposure time to capture just a few streamers instead of the more usual 'purple mush'. Images are un-enhanced except where stated, and are in roughly chronological order.
I'd built the second tower for my Marxgen
for the event, and having had no luck getting it to work in bipolar mode at home, I
started off running both stages in unipolar mode. Output was a bit disappointing at about
3 feet - little more than a single tower would do - I presume this was mainly due to
corona losses. (JacobsLadder-O-Phone in background)
Detail of spark from above image with contrast increased.
Later in the day, I hooked it up in bipolar mode, and it worked
brilliantly - I think the problems I had at home may have been due to the capacitance of
the nearby garage door.
Sparks of slightly over 4 feet were produced, with an output in the region of 1
million volts between the two towers (less corona losses. Local
sales tax may apply, YMMV....)
Spark detail, Enhanced to show forking streamers
A couple of examples from Mark Hales'
extensive collection of neon flower bulbs
Steve Connor's OLTC
Large streamer, with detail.
The edge-enhanced detail image shows the streamer rising on consecutive shots due to
thermal convection of the ionised path... but it could also be camera shake, although the
same effect is visible in at least one other photo.
Click on the left-hand image for a high-res version.
This one is definitely not down do camera shake, as the breakout
point is clearly visible and not blurred!
Steve's smaller OLTC. (right) Lighting an incandescent 30W
strip-lamp with ground current through his body...!
..and on the same subject, Phil Parry spent
a very worrying amount of time passing RF through himself from his VTTC....
Martin Dale's huge coil, completed only the
previous evening, gave an impressive performance, hitting the ceiling several times - a
distance of about 7 feet.
Martin's coil was run with a pole transformer, connected
via a slightly, <cough>, unofficial mains connection....!
Oh, dear... Phil's at it again, this time with a large
xenon flash tube and a high-pressure sodium lamp...
And as a contrast to Martin's monster, we had Derek
Woodroffe's tiny battery operated coils.
A couple of extreme close-ups of sparks from Derek's coil (50mm F1.4
with 25mm extension tube)