step 9Installing the Lens Mount
One morning I woke up and found the sun actually out. The past week had been mostly overcast , with almost no sunlight hitting the deck where this project sat. So I ran out, put on my glacier glasses and pulled the tarp off the device.
Aiming
A simple way to aim at the sun is to rotate the device until its shadows are parallel to the supports on the ground (if the ground is flat). This means the sun is directly forward. Then all you have to do is rotate it so the lens is closer to the sun, and an intense spot of light should form on the lens scaffold.
Even in the middle of winter at this latitude, a 1-inch charred spot formed in a few seconds. It wasn't exactly in the center of the plywood beam, meaning the device wasn't facing perfectly towards the sun.
Lens Mount
I didn't expect the light spot on the plywood to be so small. This meant that the focus was right on the plywood - farther than I expected. And since the lens assembly can only extend forward (towards the Fresnel), I had to recess the tube past the plywood. We accomplished this with a primitive housing made of 2x4 beams and plywood sides.
The 2x4s were ripped to a width slightly less than that of the lens tube, so the plywood sides squeezed the tube in place. If you decide to mount the lens this way, be careful not to accidentally crack the tube. But even better, think of a better way to attach it, and make the lens scaffold stick out at least 4 inches past the focal point.
Aiming
A simple way to aim at the sun is to rotate the device until its shadows are parallel to the supports on the ground (if the ground is flat). This means the sun is directly forward. Then all you have to do is rotate it so the lens is closer to the sun, and an intense spot of light should form on the lens scaffold.
Even in the middle of winter at this latitude, a 1-inch charred spot formed in a few seconds. It wasn't exactly in the center of the plywood beam, meaning the device wasn't facing perfectly towards the sun.
Lens Mount
I didn't expect the light spot on the plywood to be so small. This meant that the focus was right on the plywood - farther than I expected. And since the lens assembly can only extend forward (towards the Fresnel), I had to recess the tube past the plywood. We accomplished this with a primitive housing made of 2x4 beams and plywood sides.
The 2x4s were ripped to a width slightly less than that of the lens tube, so the plywood sides squeezed the tube in place. If you decide to mount the lens this way, be careful not to accidentally crack the tube. But even better, think of a better way to attach it, and make the lens scaffold stick out at least 4 inches past the focal point.
No comments:
Post a Comment