Saturday, January 30, 2016

did it with white

Tried with white. Built a crib to hold the fiber strand. Mounted the LED so it would aim directly at the strand. Pulled a 130 ohm resistor. At 4.5 volts, the LED would be at just over 20 mA. Boxed everything up. Did some test shots of the false star. Still couldn't see the diffraction pattern on Live View. Bumped the volts to 6.0, then 7.5.

photograph showing diffraction pattern from white LED

I was able to focus in Live View, into HI ISO, on the computer, at 200%, on the 22" monitor such that I was in perfect focus.

Probably pumping close to 50 mA through the LED...

Still not happy. I want the target to be easy! I had considered wrapping a tube of foil around the emitter. And recutting the fiber.

Glare and reflection of the box showing. Pulled some black heat shrink...

Or maybe I should rethink. Try the pinhole in foil...

Or maybe I get one of those super high output LEDs... [ed: Found 35 000 mcd units at Digi-Key.]

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